08-Segment Routing Configuration Guide

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01-SR-MPLS configuration
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Contents

Configuring SR-MPLS·· 1

About SR-MPLS· 1

SR-MPLS characteristics· 1

Basic concepts· 1

How SR-MPLS works· 1

Static segment configuration· 2

Dynamic SID allocation through an IGP· 2

Dynamic SID allocation through BGP· 3

SID allocation through BGP EPE· 3

Label forwarding entry installation based on SIDs· 3

SRLSP setup· 5

Packet forwarding in SR-MPLS· 6

MPLS SR and LDP interworking· 9

SR to LDP· 9

LDP to SR· 10

SR over LDP· 11

TI-LFA FRR· 12

TI-LFA FRR advantages· 12

TI-LFA FRR concepts· 13

TI-LFA FRR protection types· 13

TI-LFA FRR path calculation· 13

TI-LFA FRR forwarding process· 14

Microloop avoidance after a network failure· 15

Microloop avoidance after a failure recovery· 16

Protocols and standards· 17

SR-MPLS tasks at a glance· 17

IP traffic forwarding over SRLSPs tasks at a glance· 17

MPLS TE traffic forwarding over static SRLSPs tasks at a glance· 18

MPLS TE traffic forwarding over explicit paths tasks at a glance· 18

MPLS TE traffic forwarding over PCE-calculated SRLSPs tasks at a glance· 18

Configuring MPLS SRGBs· 18

Configuring the MPLS SRLB· 19

Configuring static segments· 20

Prerequisites for configuring static segments· 20

Configuring a static adjacency segment 20

Configuring a static prefix segment 21

Configuring IGP-based SID advertisement 21

IGP-based prefix SID advertisement tasks at a glance· 21

IGP-based adjacency SID advertisement tasks at a glance (for non-member interfaces) 21

IGP-based adjacency SID advertisement tasks at a glance (for member interfaces) 21

Prerequisites for configuring IGP-based SID advertisement 22

Configuring the IGP to support SR-MPLS· 22

Configuring prefix SIDs· 23

Enabling SR-MPLS adjacency label allocation for the IGP· 23

Assigning adjacency SIDs· 24

Enabling SR-MPLS adjacency SID allocation for aggregation group member interfaces· 25

Assigning adjacency SIDs to aggregation group member interfaces· 26

Configuring BGP-based SID advertisement 26

BGP-based SID advertisement tasks at a glance· 26

Prerequisites for configuring BGP-based SID advertisement 26

Configuring BGP to support MPLS SR· 27

Configuring BGP prefix SIDs· 27

Configuring BGP EPE-based SID allocation· 28

Configuring the SRLSP establishment triggering policy· 29

Configuring the device to prefer SRLSPs in traffic forwarding· 29

Configuring an MPLS TE tunnel over a static SRLSP· 30

Tasks at a glance· 30

Configuring a static SRLSP· 30

Binding a static SRLSP to an MPLS TE tunnel interface· 30

Configuring an MPLS TE tunnel over an explicit-path SRLSP· 31

Tasks at a glance· 31

Prerequisites· 31

Configuring an explicit path for the MPLS TE tunnel 31

Configuring an MPLS TE tunnel over the explicit path· 31

Configuring an MPLS TE tunnel over a PCE-calculated SRLSP· 32

Tasks at a glance· 32

Configuring an MPLS TE tunnel interface to use PCE to calculate the SRLSP· 32

Configuring IGP SR and LDP interworking· 33

Restrictions and guidelines for IGP SR and LDP interworking· 33

SR to LDP tasks at a glance· 33

LDP to SR tasks at a glance· 33

SR over LDP tasks at a glance· 33

Prerequisites for SR-MPLS and LDP internetworking· 34

Enabling advertisement of locally configured prefix-SID mappings· 34

Configuring prefix-SID mappings· 34

Enabling reception of advertised prefix-SID mappings· 35

Configuring TI-LFA FRR· 35

Restrictions and guidelines for TI-LFA FRR· 35

TI-LFA FRR tasks at a glance· 35

Enabling TI-LFA FRR· 36

Disabling an interface from participating in TI-LFA calculation· 36

Configuring microloop avoidance· 37

Verifying and maintaining MPLS SR· 39

Displaying SR label block information· 39

Displaying static segments· 39

Displaying BGP SR configuration and status information· 39

Displaying IS-IS SR configuration and status information· 39

Displaying OSPF SR configuration and status information· 40

SR-MPLS configuration examples· 40

Example: Configuring SR-MPLS based on static segments· 40

Example: Configuring SR-MPLS based on ISIS-advertised SIDs· 46

Example: Configuring an SR-based MPLS TE tunnel over an explicit path· 53

Example: Configuring SR-MPLS inter-AS option B· 58

Example: Configuring SR-MPLS inter-AS option C (I) 64

Example: Configuring SR-MPLS inter-AS option C (II) 71

Example: Configuring SR-MPLS to LDP (IS-IS) 78

Example: Configuring SR-MPLS to LDP (OSPF) 81

Example: Configuring SR-MPLS over LDP· 83

Example: Configuring IS-IS TI-LFA FRR· 88

 


Configuring SR-MPLS

About SR-MPLS

Segment Routing (SR) is a source routing technology. The source node selects a path for the packets, and then encodes the path in the packet header as an ordered list of segments. Each segment is identified by a label called the segment identifier (SID). The SR nodes along the path forward the packets based on the SIDs in the packets. Only the source node needs to maintain the path status.

SR can operate with MPLS. In an MPLS network, SR uses MPLS labels as SIDs to forward packets on an LSP.

SR-MPLS characteristics

SR-MPLS has the following characteristics:

·     SR-MPLS forwards packets based on the existing MPLS infrastructure. No infrastructure modifications are needed to implement SR on an MPLS network. For more information about the MPLS infrastructure, see MPLS basics configuration in MPLS Configuration Guide.

·     SR-MPLS expands and optimizes existing IGPs and BGP and uses the IGPs and BGP to distribute labels.

·     SR-MPLS implements network features such as MPLS TE in a simpler way, eliminating issues such as heavy and complicated routing protocol deployment.

Basic concepts

·     SR node—A node enabled with the SR-MPLS feature. The ingress node (source node) adds labels to packets. The transit nodes forward packets based on labels. The egress node removes labels and forwards packets to the destination networks. SR nodes form an SR domain.

·     Segment—An instruction an SR node executes on the incoming packet.

·     SID—Segment ID, which is MPLS label in SR-MPLS.

·     Segment type—The following types of segments are available:

¡     Prefix segment—SIDs are assigned to nodes based on destination address prefix. The nodes create prefix-specific forwarding entries.

¡     Adjacency segment—SIDs are assigned to nodes based on adjacency.

·     SRLSP—Segment routing label switched path, an LSP along which SR uses MPLS labels as SIDs to forward packets.

·     SRGB—Segment routing global block, a range of global labels dedicated for SR-MPLS prefix SIDs. Different nodes can have different SRGBs. The minimum label value of an SRGB label range is referred to as the base value of the SRGB.

·     SRLB—Segment routing local block, a range of local labels dedicated for SR-MPLS adjacency SIDs. All nodes share the same SRLB. The minimum label value of the SRLB label range is referred to as the base value of the SRLB.

How SR-MPLS works

SR-MPLS involves the following steps:

1.     Label allocation for all nodes and links along the packet forwarding paths.

The following methods are available:

¡     Static segment configuration

¡     Dynamic SID allocation through an IGP

2.     Label forwarding entry installation based on SIDs. All SR-MPLS devices in the SR domain use the allocated labels to create label forwarding entries.

3.     SRLSP setup. You can manually configure SRLSPs, or use an IGP, BGP, or a controller to dynamically create SRLSPs.

When the ingress node of an SRLSP receives a packet, it adds labels to the packet and forwards the packet to the egress node through the SRLSP. After receiving a packet from the SRLSP, the egress node removes the label and forwards the packet based on the routing table.

You can bind a higher layer application (for example, MPLS TE) to an SRLSP to forward traffic of the application through the SRLSP..

Static segment configuration

Static SR-MPLS provides the following methods for configuring static segments for a destination:

·     Prefix segment method—Manually configure the incoming label, outgoing label, and next hop for the destination address prefix on each SR node.

·     Adjacency segment method—Manually configure the incoming label and next hop for the adjacency to the neighbor on each SR node.

Dynamic SID allocation through an IGP

SR-MPLS expands IGP protocols such as IS-IS and OSPF to advertise SIDs in IGP protocol packets. SR-MPLS provides the following methods for dynamically allocating and advertising SIDs:

·     Prefix SID.

·     Adjacency SID.

Prefix SID

After you configure an SID for the loopback address on each SR node, the SIDs uniquely identify the SR nodes. All SR nodes in the SR domain use an IGP to advertise their own prefix SIDs. After receiving advertised prefix SIDs, each SR node calculates the prefix SIDs to the advertisers.

The prefix SID advertisement can be one of the following types:

·     Absolute value advertisement—Each SR node advertises the prefix SID absolute value and the SRGB.

·     Index value advertisement—Each SR node advertises the prefix SID index and the SRGB.

Each SR node is assigned a globally unique index value for the node's prefix. The prefix SID an SR node allocates to a prefix equals the SRBG base of the SR node plus the index for that prefix.

 

 

NOTE:

The device supports only the index value advertisement in the current software release.

 

Adjacency SID

SR nodes use an IGP to advertise SIDs allocated to the IGP adjacencies (that is, the links to its IGP neighbors). The SIDs are used to identify the links.

The adjacency SIDs can be allocated automatically or manually.

·     Automatic adjacency SID allocation—SR nodes allocate labels in SRLBs to the IGP adjacencies as SIDs.

·     Manual adjacency SID allocation—You can assign adjacency SID by using absolute values or index values. If you use index values, the adjacency SID of a link is the base value of the SRLB plus the index value for the link.

Dynamic SID allocation through BGP

SR-MPLS expands BGP to advertise prefix SIDs in BGP protocol packets. BGP uses routing policies to assign SIDs to prefixes when redistributing routes. The SIDs uniquely identify the SR nodes. All SR nodes in the SR domain use BGP to advertise their own prefix SIDs, including the SIDs and SID index values. From received advertisement packets, each SR node derives the prefix SIDs for the advertisers.

BGP prefix SIDs can be exchanged between BGP peers only through IPv4 unicast routes.

Dynamic SID allocation through BGP applies to MPLS VPN inter-AS option C networks.

SID allocation through BGP EPE

The BGP Egress Peer Engineering (BGP EPE) feature assigns labels to BGP peers to steer traffic across ASs to specific BGP neighbors or links.

After you configure BGP EPE on a device, the device assigns SIDs to connected BGP peers or peer groups to identify the BGP neighbors or links. These SIDs are called BGP peering SIDs or BGP peering segments.

BGP peering segments or SIDs fall into the following types:

·     Peer Node Segment (Peer Node SID)—Node type, typically assigned to a BGP neighbor that has used a directly connected interface to establish a BGP session with the device.

·     Peer Adjacency Segment (Peer Adjacency SID)—Adjacency type, typically assigned to a BGP neighbor that uses a loopback interface to establish a BGP session with the device.

·     Peer Set Segment (Peer Set SID)—Set type, typically assigned to links when multiple equal cost multi-path (ECMP) paths exist between the device and a BGP neighbor.

SIDs that BGP EPE assigns are locally significant. These SIDs are not advertised to other devices and are not affected by route types exchanged between BGP peers.

SID allocation through BGP EPE is typically used for MPLS VPN inter-AS option B.

Label forwarding entry installation based on SIDs

Label forwarding entry installation based on IGP prefix SIDs

Label forwarding entries based on prefix SIDs can be static or dynamic.

·     Static label forwarding entries—The device creates local label forwarding entries based on manually configured incoming labels, outgoing labels, and next hops.

·     Dynamic label forwarding entries—The device uses the IGP to flood in the SR domain the local SRGB and the index of the prefix SID for the local loopback interface. Based on the flooded information, the other devices in the domain calculates their local label forwarding entries by using the following rules:

¡     Incoming label = Local SRGB base value + Index

¡     Outgoing label = SRGB base value of the next hop + Index

Figure 1 Creating label forwarding entries based on IGP prefix SIDs

 

Figure 1 shows how dynamic label forwarding entries are created. After you assign index value 201 to loopback address 1.1.1.1/32 on Device C, Device C uses an IGP packet to advertise the index value and its local SRGB. Then, the devices calculate incoming and outgoing labels according to the previously mentioned label calculation rules.

·     Devices C calculates its incoming label, which is 18201.

·     Device B calculates its incoming label and outgoing label and creates a label forwarding entry. The incoming label is 17201. The outgoing label is 18201. The next hop is Device C.

·     Device A calculates its incoming label and outgoing label and creates a label forwarding entry. The incoming label is 16201. The outgoing label is 17201. The next hop is Device B.

Label forwarding entry installation based on BGP prefix SIDs

The device redistributes routes to BGP and assigns prefix SIDs to redistributed routes based on routing policies. Then, the device uses BGP to flood in the SR domain the prefix SIDs and the indexes of the prefix SIDs. Based on the flooded information, the other devices in the domain calculates their local label forwarding entries by using the following rules:

·     Incoming label = Local SRGB base value + Index

·     Outgoing label = Received SID

Figure 2 Creating label forwarding entries based on BGP prefix SIDs

 

Figure 2 shows how label forwarding entries are created. After you assign index value 201 to loopback address 1.1.1.1/32 on Device D, Device D redistributes the route of the address and assigns it an SID (16201 in this example). Then, the device uses a BGP packet to advertise the SID and index value. The devices in the SR domain calculate incoming and outgoing labels according to the previously mentioned label calculation rules and create label forwarding entries.

·     Devices D calculates its incoming label, which is 16201.

·     Device C calculates its incoming label and outgoing label and creates a label forwarding entry. The incoming label is 16201. The outgoing label is 16201. The next hop is Device D.

·     Device B calculates its incoming label and outgoing label and creates a label forwarding entry. The incoming label is 16201. The outgoing label is 16201. The next hop is Device C.

·     Device A calculates its incoming label and outgoing label and creates a label forwarding entry. The incoming label is 16201. The outgoing label is 16201. The next hop is Device B.

Label forwarding entry installation based on BGP EPE

Configure BGP EPE on border routers to assign SIDs to specific peers or peer groups.

Figure 3 Creating label forwarding entries by using BGP EPE

 

As shown in Figure 3, you can configure BGP EPE on Device B to assign BGP peering SIDs to EBGP neighbors Device C and Device D. BGP peering SIDs are locally significant and are not advertised to neighbors.

Label forwarding entry installation based on adjacency SIDs

When using adjacency SIDs, each device allocates a static or dynamic incoming label to the link to its neighbor. The label has local significance. Multiple devices can use the same adjacency SID.

Figure 4 Creating label forwarding entries based on adjacency SIDs

 

As shown in Figure 4, the devices are running the same IGP. After IGP adjacencies are established between the devices, Device A, Device B, and Device C allocates labels and creates label forwarding entries as follows:

·     Device A allocates label 203 to the link to its neighbor Device B.

·     Device B allocates label 202 to the link to its neighbor Device C.

·     Device C allocates label 201 to the link to its neighbor Device D.

·     Device A creates a label forwarding entry with incoming label 203 and next hop Device B.

·     Device B creates a label forwarding entry with incoming label 202 and next hop Device C.

·     Device C creates a label forwarding entry with incoming label 201 and next hop Device D.

SRLSP setup

You can use the following methods to create SRLSPs:

·     Manually configure an SRLSP.

To configure an SRLSP, you must specify the label stack for packets to be forwarded along the SRLSP on the ingress node. Each label in the stack corresponds to a prefix SID or adjacency SID. The system can look for the outgoing label and next hop based on the prefix SID or adjacency SID.

·     Configure SR nodes to use BGP or an IGP to dynamically establish an SRLSP.

SR nodes follow these steps to establish SRLSPs:

a.     Use BGP or an IGP to collect prefix SID information from the SR-MPLS network.

b.     Calculate the shortest paths to other SR nodes based on the collected prefix SID information and the BGP or IGP network topology.

c.     Establish SRLSPs based on the shortest paths.

·     Configure a controller to deploy SRLSP configuration to the device so the device creates SRLSPs.

For more information about controller configuration, see the user guide for the controller.

Packet forwarding in SR-MPLS

Based on the SID allocation method, SR-MPLS uses one of the following packet forwarding methods:

·     Prefix SID-based packet forwarding—The ingress node encapsulates the prefix SID for the egress node to a packet. The transit nodes forward the packet based on label forwarding entries.

·     Adjacency SID-based packet forwarding—The ingress node encapsulates the label stack that contains the adjacency SIDs of all links along the forwarding path to a packet. Each transit node uses the top label in the label stack to determine the next hop and pops the top label before forwarding the packet to the next hop.

·     Prefix and adjacency SID-based packet forwarding—The nodes use prefix SID-based packet forwarding in combination with adjacency-based packet forwarding.

Prefix SID-based packet forwarding within the same AS

Figure 5 shows how a packet is forwarded along the SRLSP from Device A to Device E based on prefix SIDs. In this example, the outgoing label for the packet is 21201 on Device A.

1.     Ingress node Device A searches for a forwarding entry for label 21201, adds outgoing label 20201 to the packet and sends the packet to the next hop (Device B).

2.     When transit node Device B receives the packet, it searches for a label forwarding entry that matches the label in the packet. Then, Device B uses the outgoing label of the matched entry (19201) to replace the label in the packet and forwards the packet to the next hop (Device C).

3.     Transit nodes Device C and Device D process the packet in the same way Device B does.

4.     When egress node Device E receives the packet, it removes the label and forwards the packet by IP address.

Figure 5 Prefix SID-based packet forwarding within the same AS

 

Prefix SID-based packet forwarding across ASs

Figure 6 shows how a packet is forwarded along the SRLSP from Device A to Device D based on prefix SIDs. In this example, the outgoing label for the packet is 16201 on Device A.

1.     Ingress node Device A searches for a forwarding entry for label 16201, adds outgoing label 16201 to the packet, and sends the packet to the next hop (Device B).

2.     When transit node Device B receives the packet, it searches for a label forwarding entry that matches the label in the packet (16201). Then, Device B uses the outgoing label of the matched entry (16201) to replace the label in the packet and forwards the packet to the next hop (Device C).

3.     Transit nodes Device C processes the packet in the same way Device B does.

4.     When egress node Device D receives the packet, it removes the label and forwards the packet by IP address.

Figure 6 Prefix SID-based packet forwarding across ASs

 

BGP EPE-based packet forwarding across ASs

As shown in Figure 7, you can configure BGP EPE and an SRLSP used for the MPLS TE tunnel on Device B to steer packets to travel through Device C or Device D to Device E. In this example, packets travel from Device A through Device B and Device D to Device E. Device B uses BGP EPE to assign SID 6000 to Device D. A static SRLSP is established between Device B and Device D for the MPLS TE tunnel and Device B also assigns SID 6000 to the SRLSP.

1.     Within AS 100, source node Device A adds label 17204 to the packet according to the SRLSP, and sends the packet to Device B.

2.     When Device B receives the packet, it searches for a label forwarding entry and finds that it should forward the packet through the MPLS TE tunnel. Then, Device B removes label 17204 from the packet, and forwards the packet through the MPLS TE tunnel to Device D.

3.     Within AS 200, Device D searches for a label forwarding entry based on the SRLSP, adds label  18201 to the packet, and sends the packet to Device E.

4.     When egress node Device E receives the packet, it removes label 18201 and forwards the packet by IP address.

Figure 7 BGP EPE-based packet forwarding across ASs

 

Adjacency SID-based packet forwarding

Figure 8 shows how a packet is forwarded along the SRLSP from Device A to Device E based on adjacency SIDs. In this example, the label stack for the packet is configured as (200, 201, 202, and 203) on Device A.

1.     Ingress node Device A searches for a forwarding entry for the top label (200) to determine the next hop. Then, Device A adds label stack (201, 202, and 203) to the packet, and forwards the packet to the next hop (Device B).

2.     When transit node Device B receives the packet, it searches for a forwarding entry for the top label (201) to determine the next hop. Then, Device B removes the top label from the stack and forwards the packet to the next hop (Device C).

3.     When transit node Device C receives the packet, it searches for a forwarding entry for the top label (202) to determine the next hop. Then, Device C removes the top label from the stack and forwards the packet to the next hop (Device D).

4.     When transit node Device D receives the packet, it searches for a forwarding entry for the label (203) to determine the next hop. Then, Device D removes the label stack from the packet and forwards the packet to the next hop (Device E).

5.     When egress node Device E receives the packet, it forwards the packet by IP address.

Figure 8 Adjacency SID-based packet forwarding

 

Prefix and adjacency SID-based packet forwarding

Figure 9 shows how a packet is forwarded along the SRLSP from Device A to Device E based on prefix SIDs and adjacency SIDs. In this example, the index value for the prefix SID of Device C is 1. The prefix SIDs for Device A, Device B, and Device C are 18001, 17001, and 16001, respectively. The Adjacency SIDs that Device C and Device D allocate to the adjacencies are 16 and 17, respectively. On Device A, the label stack for the packet is (18001, 16, 17).

1.     Ingress node Device A searches for a forwarding entry for label 18001 to determine the outgoing label (17001) and next hop (Device B). Device A swaps label 18001 with 17001. Then, it adds label stack (17001, 16, 17) to the packet and sends the packet to the next hop (Device B).

2.     When transit node Device B receives the packet, it searches for a label forwarding entry that matches the top label in the label stack (17001). Then, Device B uses the outgoing label of the matched entry (16001) to replace the top label and forwards the packet to the next hop (Device C).

3.     When transit node Device C receives the packet, it removes the top label 16001 and searches for a forwarding entry for the next label (16) to determine the next hop. Then, Device C removes label 16 from the stack and forwards the packet to the next hop (Device D).

4.     When transit node Device D receives the packet, it searches for a forwarding entry for the label (17) to determine the next hop. Then, Device D removes the label stack from the packet and forwards the packet to the next hop (Device E).

5.     When egress node Device E receives the packet, it forwards the packet by IP address.

Figure 9 Prefix and adjacency SID-based packet forwarding

 

MPLS SR and LDP interworking

IGP SR and LDP interworking enables SR-MPLS networks that use an IGP for SID advertisement to communicate and cooperate with MPLS LDP networks.

IGP SR and LDP interworking supports the following modes:

·     SR to LDP—Maps prefixes on an LDP network to SR-MPLS SIDs to forward traffic from an SR-MPLS network to an MPLS LDP network.

·     LDP to SR—Uses an IGP protocol to advertise SIDs and associates SIDs with LDP labels to forward traffic from an MPLS LDP network to an SR-MPLS network.

·     SR over LDP—Enables SR-MPLS networks to communicate through an LDP network.

SR to LDP

The SR to LDP mode defines the following roles:

·     Segment Routing Mapping Server (SRMS)—Advertises prefix-SID mappings on behalf of SR-incapable devices (LDP devices). You must configure prefix-SID mappings on the SRMS.

·     Segment Routing Mapping Client (SRMC)—Receives prefix-SID mappings advertised by the SRMS and creates SR-MPLS label forwarding entries.

As shown in Figure 10, Device A and Device B are running SR-MPLS, and Device B, Device C, and Device D are running LDP. After Device D assigns a label for destination address 3.3.3.3/32, Device B and Device C each install an LDP label forwarding entry.

The following steps establish a mapping between the SRLSP and the LDP LSP:

1.     Device B acts as an SRMS. It assigns SID index value 201 to the IP address of loopback interface 0 on Device D (3.3.3.3/32), and then advertises an IP prefix-SID mapping TLV to Device A.

2.     Device A acts as an SRMC. After receiving the advertised mapping TLV, it creates an SR-MPLS label forwarding entry.

A mapping is established between the SRLSP and the LDP LSP.

Figure 10 SR to LDP packet forwarding

 

If Device A uses an SRLSP to send a packet to Device D, the packet is forwarded as follows:

3.     Ingress node Device A adds label 18201 to the packet and then sends the packet to transit node Device B.

4.     When transit node Device B receives the packet, it searches for a label forwarding entry that matches incoming label 18201. Because the entry does not have an outgoing label, Device B searches for a valid LDP outgoing label for destination address 3.3.3.3/32. Then, Device B adds the LDP label (20) to the packet as the SR outgoing label and forwards the packet to the next hop (Device C).

5.     When transit node Device C receives the packet, it searches for an LDP label forwarding entry for incoming label 20. Then, it removes the label from the packet and forwards the packet to egress node Device D.

6.     The egress node forwards the packet by IP address.

LDP to SR

As shown in Figure 11, Device C and Device D are running SR-MPLS, and Device A, Device B, and Device C are running LDP. Each device running LDP assigns a label to destination address 3.3.3.3/32 and then installs an LDP label forwarding entry.

The following steps establish an association between the SR-MPLS label and the LDP label:

1.     After you assign SID index value 201 to the IP address of loopback interface 0 on Device D (3.3.3.3/32), Device D sends an IGP protocol packet to advertise the index value and the local SRGB.

2.     After receiving the packet, Device C creates an SR-MPLS label forwarding entry.

The SR-MPLS label and the LDP label are associated on Device C.

Figure 11 LDP to SR packet forwarding

 

A packet from Device A to Device D is forwarded as follows:

3.     Ingress node Device A adds an LDP label (20) to the packet and forwards the packets to the next hop (Device B).

4.     Device B searches for an LDP label forwarding entry, uses 30 as the outgoing label, and forwards the packet to the next hop (Device C).

5.     Device C searches for an LDP label forwarding entry for incoming label 30 and finds no outgoing label. Because valid SR-MPLS outgoing label 16201 exists for the destination address 3.3.3.3.32, Device C uses the label (16201) as the outgoing label and forwards the packet to Device D.

6.     Egress node Device D deletes label 16201 from the packet and forwards the packet by IP address.

7.      

SR over LDP

For SR-MPLS networks to communicate across an LDP network, the SR/LDP border devices must be able to connect the SR LSP and the LDP LSP as follows:

·     SR-MPLS to LDP interwoking—The border device installs SR-to-LDP label forwarding entries. For a packet from the SR-MPLS network to the LDP network, the SR-MPLS label forwarding entry on the border device does not have an outgoing label. The border device uses the outgoing label of the LDP label forwarding entry for the same destination address as the outgoing label of the packet.

·     LDP to SR-MPLS interwoking—The border device installs LDP-to-SR label forwarding entries. For a packet from the LDP network to the SR-MPLS network, the LDP forwarding entry on the border device does not have an outgoing label. The border device must use the outgoing label of the SR-MPLS forwarding entry for the same destination address as the outgoing label of the packet.

Figure 12 SR-MPLS over LDP

 

As shown in Figure 12, Device A, Device B, Device D, and Device E are running SR-MPLS. After you assign index value 201 to loopback interface address 3.3.3.3/32 on Device E, Device E will advertise the index value and the local SRGB. After Device A, Device B, and Device D receive the message, they will install their respective SR-MPLS label forwarding entries. Device B, Device C, and Device D are running LDP. They allocate labels to destination address 3.3.3.3/32 to generate the LDP label forwarding entries.

A packet that Device A sends to Device E will be forwarded as follows:

1.     Ingress node Device A encapsulates label 18201 to the packet and forwards the packet to transit node Device B.

2.     Transit node Device B searches for an SR-MPLS label forwarding entry for incoming label 18201 and finds that the entry does not have an outgoing label. Because an LDP label forwarding entry with outgoing label 20 exists for the destination address (3.3.3.3/32), Device B encapsulates outgoing label 20 in the packet. Then Device B sends the packet to transit node Device C.

3.     Device C forwards the packet to Device D based on its LDP label forwarding entries. The outgoing label is 30.

4.     Device D searches for an LDP label forwarding entry for incoming label 30 and finds that the entry does not have an outgoing label. Because an SR-MPLS label forwarding entry with outgoing label 16201 exists for the destination address (3.3.3.3/32), Device B encapsulates outgoing label 16201 in the packet. Then Device D sends the packet to egress node Device E.

5.     Egress node Device E deletes the incoming label and forwards the packet by IP address.

TI-LFA FRR

Topology-Independent Loop-Free Alternate Fast Re-Route (TI-LFA FRR) provides link and node protection. When a link or node fails, TI-LFA FRR switches the traffic to the backup path to ensure continuous data forwarding.

TI-LFA FRR advantages

SR-based TI-LFA FRR has the following advantages:

·     It satisfies the basic requirements for IP FRR fast convergence.

·     Traffic protection is not affected by the network environment.

·     The algorithm is not too complicated.

·     It uses the converged route as the backup path. All devices have finished route convergence before the forward process begins.

TI-LFA FRR concepts

·     P space—Use the source node of the protected link as the root to establish a shortest path tree. All nodes that are reachable from the source node without passing the protected link form the P space. Nodes in the P space are called P nodes.

·     Extended P space—Use the source node of the protected link and its neighbors as the roots to establish shortest path trees. All nodes that are reachable from the source node or one of its neighbors without passing the protected link form the extended P space. The P space is a subset of the extended P space.

·     Q space—Use the destination node of the protected link as the root to establish a reverse shortest path tree. All nodes that are reachable from the root node without passing the protected link form the Q space. Nodes in the Q space are called Q nodes.

·     TI-LFA algorithm—In real networks, the P space and Q space do not have common nodes or directly connected nodes. The device cannot calculate the backup path and cannot meet the high availability requirement. The TI-LFA algorithm can calculate the extended P space, Q space, converged shortest path tree, repair list, and backup output interface for the protected link to get the backup next hop.

·     Repair list—A constraint path used to indicate how a P node reaches a Q node when the P space and Q space do not have common nodes. The repair list contains the following labels (SIDs):

¡     Labels of P nodes.

¡     Adjacency labels from P nodes to Q nodes.

TI-LFA FRR protection types

The following TI-LFA traffic protection types are available:

·     Link protection—Protects traffic that traverses a specific link.

·     Node protection—Protects traffic that traverses a specific node.

Node protection takes precedence over link protection.

TI-LFA FRR path calculation

As shown in Figure 13, PE 1 is the source node. P 1 is the faulty node. PE 2 is the destination node. The numbers on links represent the link costs. A data flow traverses PE 1, P 1, and PE 2. To protect data against P 1 failure, TI-LFA FRR calculates the extended P space, Q space, shortest path tree converged after P 1 fails, repair list, and backup output interface, and creates the backup forwarding entry.

TI-LFA FRR calculates the backup path by using the following steps:

1.     Calculates the extended P space: P 2.

2.     Calculates the Q space: PE 2 and P 4.

3.     Calculates the shortest path tree converged after P 1 fails: PE 1 --> P 2 --> P 4 --> PE 2.

4.     Calculates the repair list: Node label of P 2 (16030), adjacency label of P 2 to P 3 (2168), and adjacency label of P 3 to P 4 (2178).

5.     Calculates the backup output interface, that is, the output interface to the next hop after the link from PE 1 to P 1 fails.

Figure 13 TI-LFA FRR diagram

 

TI-LFA FRR forwarding process

After TI-LFA FRR finishes backup path calculation, traffic will be switched to the backup path in response to a primary path failure.

As shown in Figure 14, P 2 is a P node and P 4 is a Q node. When the next hop on the primary path (P 1) fails, TI-LFA FRR switches the traffic to the backup path. The following are the detailed steps:

1.     PE 1 encapsulates a label stack to a packet according to the repair list. The labels, from the outmost to inmost, are as follows:

¡     Node label of P node P2 (16030), which equals the SRGB base value of P 2 plus the SID index value of P 2.

¡     Adjacency labels from P node P2 to Q node P 4, which are 2168 and 2178.

¡     The destination's node label 17010, which equals the SRGB base value of Q node P 4 plus the SID index value of destination node PE 2.

2.     P2 receives the packet, searches for a label forwarding entry based on the outmost label, pops label 2168, and forwards the packet to P 3.

3.     P3 receives the packet, searches for a label forwarding entry based on the outmost label, pops label 2178, and forwards the packet to P 4.

4.     P4 receives the packet, and searches for a label forwarding entry based on the outmost label. Because the outgoing label is 18010 and the next hop is PE 2, P 4 encapsulates 18010 as the outmost label and forwards the packet to PE 2.

Figure 14 Data forwarding over the TI-LFA FRR backup path

 

Microloop avoidance after a network failure

As shown in Figure 15, when Device B fails, traffic to Device C will be switched to the backup path calculated by TI-LFA. After Device A finishes route convergence, traffic will be switched to the post-convergence path. If Device D and Device F have not finished route convergence and still forward traffic along the pre-convergence path, a loop is formed between Device A and Device F. The loop exists until Device D and Device F finish route convergence.

FRR microloop avoidance and SR microloop avoidance can resolve this issue. After you configure TI-LFA, Device A first switches traffic to the backup path calculated by TI-LFA when Device B fails. Then, Device A waits for Device D and Device F to finish route convergence before starting route convergence. After Device A also finishes route convergence, Device A switches the traffic to the converged route.

Figure 15 Diagram for microloop avoidance after a network failure

 

 

Microloop avoidance after a failure recovery

As shown in Figure 16, before the link between Device B and Device C recovers, traffic traverses along the backup path. After the link recovers, Device A will forward the traffic to Device B if Device A finishes route convergence before Device B. Before Device B also finishes route convergence, Device B still forwards the traffic along the backup path. A loop is formed between Device A and Device B.

SR microloop avoidance can resolve this issue. After the link recovers, SR microloop avoidance automatically calculates the optimal path from Device A to Device C and forwards traffic along the path. To forward a packet along the newly calculated path, Device A adds, for example, the adjacency label from Device B to Device C to the packet and then sends the packet to Device B. Then, Device B forwards the packet to Device C based on the path information.

When the microloop avoidance RIB-update-delay timer expires, Device B should have finished route convergence. Device A does not add path information to packets anymore, and it forwards packets to Device C as usual.

Figure 16 Diagram for microloop avoidance after a failure recovery

 

Protocols and standards

·     draft-bashandy-rtgwg-segment-routing-ti-lfa-04

·     draft-ietf-spring-segment-routing-mpls-00

·     draft-ietf-spring-segment-routing-02

·     draft-ietf-isis-segment-routing-extensions-06

·     draft-ietf-spring-segment-routing-11

·     3draft-ietf-idr-bgpls-segment-routing-epe-15

·     draft-ietf-idr-bgp-prefix-sid-19

·     RFC 7752, North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP

SR-MPLS tasks at a glance

IP traffic forwarding over SRLSPs tasks at a glance

To forward IP traffic over SRLSPs, perform the following configuration tasks:

1.     Configuring segments

Select one of the following tasks:

¡     Configuring static segments

¡     Configuring IGP-based SID advertisement

2.     Configuring the SRLSP establishment triggering policy

3.     (Optional.) Configuring the device to prefer SRLSPs in traffic forwarding

4.     (Optional.) Configuring IGP SR and LDP interworking

5.     (Optional.) Configuring TI-LFA FRR

MPLS TE traffic forwarding over static SRLSPs tasks at a glance

To forward MPLS TE traffic over static SRLSPs, perform the following configuration tasks:

1.     Configuring segments

Select one of the following tasks:

¡     Configuring static segments

¡     Configuring IGP-based SID advertisement

¡     Configuring BGP-based SID advertisement

¡     Configuring BGP EPE-based SID allocation

2.     Configuring an MPLS TE tunnel over a static SRLSP

3.     (Optional.) Configuring IGP SR and LDP interworking

4.     (Optional.) Configuring TI-LFA FRR

MPLS TE traffic forwarding over explicit paths tasks at a glance

To forward MPLS TE traffic over explicit paths, perform the following configuration tasks:

1.     Configuring IGP-based SID advertisement

2.     Configuring an MPLS TE tunnel over an explicit-path SRLSP

3.     (Optional.) Configuring IGP SR and LDP interworking

4.     (Optional.) Configuring TI-LFA FRR

MPLS TE traffic forwarding over PCE-calculated SRLSPs tasks at a glance

To forward MPLS TE traffic over PCE-calculated SRLSPs, perform the following configuration tasks:

1.     Configuring an MPLS TE tunnel over a PCE-calculated SRLSP

2.     (Optional.) Configuring IGP SR and LDP interworking

3.     (Optional.) Configuring TI-LFA FRR

Configuring MPLS SRGBs

Restrictions and guidelines

The global MPLS SRGB is used for static prefix segments and BGP prefix SIDs. If no MPLS SRGB is configured for a protocol process, the process uses the global MPLS SRGB.

If you have configured prefix SIDs when you configure an SRGB, the SRGB must contain the configured prefix SIDs.

In the following situations, a configured SRGB takes effect after a device reboot:

·     The SRGB contains a label that is already used by another protocol. For example, the SRGB contains a label that is already used by LDP.

·     The SRGB overlaps with the label range of another protocol.

Configuring the global MPLS SRGB

1.     Enter system view.

system-view

2.     Enter segment routing view.

segment-routing

3.     Configure the global MPLS SRGB.

global-block minivalue maxivalue

By default, the global MPLS SRGB is from 16000 to 55999.

Configuring the MPLS SRGB for IS-IS

1.     Enter system view.

system-view

2.     Enter IS-IS view.

isis process-id

3.     Configure the MPLS SRGB.

segment-routing global-block minivalue maxivalue

By default, the MPLS SRGB for an IS-IS process is the same as the global MPLS SRGB configured in segment routing view.

Configuring the MPLS SRGB for OSPF

1.     Enter system view.

system-view

2.     Enter OSPF view.

ospf process-id

3.     Configure the MPLS SRGB.

segment-routing global-block minivalue maxivalue

By default, the MPLS SRGB for an OSPF process is the same as the global MPLS SRGB configured in segment routing view.

Configuring the MPLS SRLB

About this task

The segment routing local block (SRLB) is the range of local labels dedicated for SR-MPLS adjacency SIDs.

Restrictions and guidelines

Before configuring the MPLS SRLB, use the display mpls label command to display MPLS label usage information. Make sure that all labels in the specified range are idle. If a label in the range is not idle, the configured MPLS SRLB takes effect only after you save the running configuration and reboot the device. For more information about the display mpls label command, see MPLS Command Reference.

Procedure

1.     Enter system view.

system-view

2.     Enter segment routing view.

segment-routing

3.     Configure the MPLS SRLB.

local-block minimum-value maximum-value

By default, the MPLS SRLB is from 15000 to 15999.

Configuring static segments

Prerequisites for configuring static segments

Before you configure static segments, perform the following tasks:

·     Determine the ingress node, transit nodes, and egress node of a static SRLSP.

·     Determine the incoming label for the adjacency segment from a node to next hop of the node. Determine the incoming label for the destination IP address for the prefix segment on each node. On a device, a static SRLSP, a static LSP, and a static CRLSP cannot use the same incoming label.

·     Enable MPLS on all nodes and interfaces that will participate in MPLS forwarding. For information about enabling MPLS, see basic MPLS configuration in MPLS Configuration Guide.

Configuring a static adjacency segment

Restrictions and guidelines

This task is required on all nodes of a static SRLSP.

Multiple static SRLSPs can share an adjacency segment.

If you specify the next hop address for a static adjacency segment, make sure the following requirements are met:

·     The device has a route to the next hop address.

·     MPLS is enabled on the output interface of the route.

If you specify an output interface for a static adjacency segment, make sure the following requirements are met:

·     The interface is up.

·     The interface can receive direct routes.

·     MPLS is enabled on the interface.

A static adjacency segment must use a different incoming label than existing static LSPs, static PWs, and static CRLSPs. If not, the configured adjacency segment is unavailable. The adjacency segment cannot become available even if you change the incoming label of the static LSP, static PW, or static CRLSP. To resolve this problem, you must delete the existing adjacency segment and configure a new one with a different incoming label.

Procedure

1.     Enter system view.

system-view

2.     Configure a static adjacency segment.

static-sr-mpls adjacency adjacency-path-name in-label label-value { nexthop ip-address | outgoing-interface interface-type interface-number }

The next hop address for a static adjacency segment cannot be a local public IP address.

Configuring a static prefix segment

Restrictions and guidelines

This task is required on all nodes of a static SRLSP.

Multiple static SRLSPs to the same destination can share a prefix segment.

A prefix segment must use the next hop or output interface of the optimal route (non-BGP route) to the destination address of the prefix segment. You can configure multiple prefix segments to the destination address for load sharing if the optimal route has more than one next hop or output interface. To avoid configuration failure, make sure all prefix segments use the same prefix segment name and incoming label.

Procedure

1.     Enter system view.

system-view

2.     Configure a static prefix segment.

static-sr-mpls prefix prefix-path-name destination ip-address { mask-length | mask } in-label in-label-value [ { nexthop ip-address | outgoing-interface interface-type interface-number } out-label out-label-value ]

The next hop address for a static prefix segment cannot be a local public IP address.

Configuring IGP-based SID advertisement

IGP-based prefix SID advertisement tasks at a glance

Perform the following tasks on each node along an SRLSP:

1.     Configuring the IGP to support SR-MPLS

2.     Configuring prefix SIDs

3.     Configuring MPLS SRGBs

IGP-based adjacency SID advertisement tasks at a glance (for non-member interfaces)

Perform the following tasks on each node along an SRLSP:

1.     Configuring the IGP to support SR-MPLS

2.     Enabling SR-MPLS adjacency label allocation for the IGP

The device will allocate SIDs to adjacencies randomly.

3.     (Optional.) Assigning adjacency SIDs

You can assign adjacency SIDs to adjacencies manually.

4.     Configuring the MPLS SRLB

IGP-based adjacency SID advertisement tasks at a glance (for member interfaces)

Perform the following tasks on each node along an SRLSP:

1.     Configuring the IGP to support SR-MPLS

2.     Enabling SR-MPLS adjacency SID allocation for aggregation group member interfaces

3.     (Optional.) Assigning adjacency SIDs to aggregation group member interfaces

You can assign adjacency SIDs to adjacencies on aggregation group member interfaces manually.

4.     Configuring the MPLS SRLB

Prerequisites for configuring IGP-based SID advertisement

Before you configure IGP-based SID advertisement, perform the following tasks:

·     Determine the ingress node, transit nodes, and egress node of an SRLSP.

·     Determine the SIDs, MPLS SRGBs, and MPLS SRLBs for nodes.

·     Enable MPLS on all nodes and interfaces that will participate in MPLS forwarding. For information about enabling MPLS, see basic MPLS configuration in MPLS Configuration Guide.

Configuring the IGP to support SR-MPLS

Prerequisites

For SR-MPLS to take effect, perform the following tasks before configuring the IGP to support SR-MPLS:

·     If the IGP is IS-IS, set the cost style to wide, compatible, or wide-compatible before configuring IS-IS to support SR-MPLS. For more information about the cost style, see IS-IS configuration in Layer 3IP Routing Configuration Guide.

·     If the IGP is OSPF, enable opaque LSA reception and advertisement capability. For more information about the capability, see OSPF configuration in Layer 3IP Routing Configuration Guide.

Configuring IS-IS to support SR-MPLS

1.     Enter system view.

system-view

2.     Enter IS-IS view.

isis process-id

3.     Enter IS-IS IPv4 unicast address family view.

address-family ipv4

4.     Enable SR-MPLS.

segment-routing mpls

By default, SR-MPLS is disabled.

Configuring OSPF to support SR-MPLS

1.     Enter system view.

system-view

2.     Enter OSPF view.

ospf process-id

3.     Enable SR-MPLS.

segment-routing mpls

By default, SR-MPLS is disabled.

Configuring prefix SIDs

About this task

Configuring a prefix SID in lookback interface view binds the SID with the IP address of the loopback interface.

To configure a prefix SID, use one of the following methods:

·     Specify an absolute value. The absolute value is used as the prefix SID. The prefix SID takes effect only if the absolute value is in the SRGB of the node.

·     Specify an index value. The sum of the index value and the SRGB base value is used as the prefix SID. The prefix SID takes effect only if it is in the SRGB.

Restrictions and guidelines

To use a prefix SID for a group of SR nodes in anycast scenarios, specify the n-flag-clear keyword to set the Node-SID flag bit of the prefix SID to 0.

To configure an IS-IS prefix SID, you must enable an IS-IS process on the loopback interface.

Configuring an IS-IS prefix SID

1.     Enter system view.

system-view

2.     Enter loopback interface view.

interface loopback interface-number

3.     Configure an IS-IS prefix SID.

isis [ process-id process-id ] prefix-sid { absolute absolute-value | index index-value } [ n-flag-clear | { explicit-null | no-php } ] *

By default, no IS-IS prefix SID is configured.

Configuring an OSPF prefix SID

1.     Enter system view.

system-view

2.     Enter loopback interface view.

interface loopback interface-number

3.     Configure an OSPF prefix SID.

ospf process-id prefix-sid { absolute absolute-value | index index-value } [ n-flag-clear | { explicit-null | no-php } ] *

By default, no OSPF prefix SID is configured.

 

Enabling SR-MPLS adjacency label allocation for the IGP

Restrictions and guidelines

For this feature to take effect, you must enable SR-MPLS.

Enabling SR-MPLS adjacency label allocation for IS-IS

1.     Enter system view.

system-view

2.     Enter IS-IS view.

isis process-id

3.     Enter IS-IS IPv4 unicast address family view.

address-family ipv4

4.     Enable SR-MPLS adjacency label allocation.

segment-routing adjacency enable

By default, SR-MPLS adjacency label allocation is disabled.

Enabling SR-MPLS adjacency SID allocation for OSPF

1.     Enter system view.

system-view

2.     Enter OSPF view.

ospf process-id

3.     Enable SR-MPLS adjacency SID allocation.

segment-routing adjacency enable

By default, SR-MPLS adjacency SID allocation is disabled.

 

Assigning adjacency SIDs

About this task

After you enable SR-MPLS adjacency label allocation, the device randomly allocates adjacency SIDs to the links to its IGP neighbors. If the link to an IGP neighbor flaps, the adjacency SID of the link keeps changing. For a link to always use the same adjacency SID, use this feature to assign a specific adjacency SID to the link.

If you assign the same adjacency SID to the adjacencies on multiple interfaces, multiple forwarding paths are available for adjacency SID-based forwarding. By default, packets are assigned to the adjacencies evenly. If the adjacencies have different bandwidths, you can set the load balancing weights for the adjacencies to avoid congestion. The traffic ratio on an adjacency will be its load balancing weight divided by the total load balancing weights of the adjacencies with the same adjacency SID.

Restrictions and guidelines

To assign adjacency SIDs by using absolute values, make sure the SIDs are in the label range of the SRLB. To assign adjacency SIDs by using index values, make sure the index values plus the base value of the SRLB are in the label range of the SRLB.

The assigned adjacency SIDs take effect after you enable SR-MPLS and SR-MPLS adjacency label allocation.

Prerequisites

Before assigning adjacency SIDs, execute the display mpls label command to display the usage status of the labels that you want to assign as adjacency SIDs. Make sure the labels are in Idle state.

A label that is not in Idle state is being used by another protocol. If you assign it to a link as an adjacency SID, the adjacency SID is not available even if the status of the label changes to Idle later. To use the adjacency SID, you must remove the adjacency SID assignment and assign the adjacency SID again.

Assigning adjacency SIDs to IS-IS adjacencies

1.     Enter system view.

system-view

2.     Enter interface view.

interface interface-type interface-number

3.     Assign an adjacency SID to an IS-IS adjacency.

isis adjacency-sid { absolute absolute-value | index index-value } [ nexthop nexthop-address ]

By default, an IS-IS adjacency does not have an adjacency SID.

4.     (Optional.) Set the load balancing weight for an IS-IS adjacency.

isis adjacency-sid weight weight-value

By default, the load balancing weight for an IS-IS adjacency is not set.

Assigning adjacency SIDs to OSPF adjacencies

5.     Enter system view.

system-view

6.     Enter interface view.

interface interface-type interface-number

7.     Assign an adjacency SID to an OSPF adjacency.

ospf adjacency-sid { absolute absolute-value | index index-value } [ nexthop nexthop-address ]

By default, an OSPF adjacency does not have an adjacency SID.

8.     (Optional.) Set the load balancing weight for an OSPF adjacency.

ospf adjacency-sid weight weight-value

By default, the load balancing weight for an OSPF adjacency is not set.

Enabling SR-MPLS adjacency SID allocation for aggregation group member interfaces

About this task

In an SR-MPLS domain with Layer 3 aggregate links between SR nodes, you can enable SR-MPLS adjacency SID allocation for aggregation group member interfaces. Then, the system will assign adjacency SIDs to links on member interfaces of a Layer 3 aggregation group so traffic goes out of specific member interfaces. If you do not enable SR-MPLS adjacency SID allocation for aggregation group member interfaces, traffic will be load balanced on all member interfaces in the aggregation group.

Restrictions and guidelines

Before enabling SR-MPLS adjacency SID allocation for aggregation group member interfaces, make sure SR-MPLS is enabled.

Enabling SR-MPLS adjacency SID allocation for IS-IS

1.     Enter system view.

system-view

2.     Enter IS-IS view.

isis process-id

3.     Enter IS-IS IPv4 unicast address family view.

address-family ipv4

4.     Enable SR-MPLS adjacency SID allocation for aggregation group member interfaces.

segment-routing member-port adjacency enable

By default, SR-MPLS adjacency SID allocation is disabled for aggregation group member interfaces.

Assigning adjacency SIDs to aggregation group member interfaces

About this task

After you enable adjacency SID allocation for aggregation group member interfaces, the device randomly allocates adjacency SIDs to the links to its IGP neighbors on aggregation group member interfaces. If the link to a neighbor flaps, the adjacency SID of the link keeps changing. For a link to always use the same adjacency SID, you can assign a specific adjacency SID to the link.

Restrictions and guidelines

To assign adjacency SIDs by using absolute values, make sure the SIDs are in the label range of the SRLB. To assign adjacency SIDs by using index values, make sure the index values plus the base value of the SRLB are in the label range of the SRLB.

The assigned adjacency SIDs take effect after you enable SR-MPLS and SR-MPLS adjacency SID allocation for aggregation group member interfaces.

Prerequisites

Before assigning adjacency SIDs, execute the display mpls label command to display the usage status of the labels that you want to assign as adjacency SIDs. Make sure the labels are in Idle state.

A label that is not in Idle state is being used by another protocol. If you assign it to a link as an adjacency SID, the adjacency SID is not available even if the status of the label changes to Idle later. To use the adjacency SID, you must remove the adjacency SID assignment and assign the adjacency SID again.

Assigning adjacency SIDs to IS-IS adjacencies

1.     Enter system view.

system-view

2.     Enter Layer 3 Ethernet interface view.

interface interface-type interface-number

3.     Assign an adjacency SID to an IS-IS adjacency.

isis process-id member-port adjacency-sid { absolute absolute-value | index index-value } nexthop nexthop-address

By default, an IS-IS adjacency does not have an adjacency SID.

Configuring BGP-based SID advertisement

BGP-based SID advertisement tasks at a glance

Perform the following tasks on each node along an SRLSP:

1.     Configuring BGP to support MPLS SR

2.     Configuring BGP prefix SIDs

Prerequisites for configuring BGP-based SID advertisement

Before you configure BGP-based SID advertisement, perform the following tasks:

·     Determine the ingress node, transit nodes, and egress node of an SRLSP.

·     Determine the index value for the prefix SID of each node:

·     Enable MPLS on all nodes and interfaces that will participate in MPLS forwarding. For information about enabling MPLS, see basic MPLS configuration in MPLS Configuration Guide.

Configuring BGP to support MPLS SR

1.     Enter system view.

system-view

2.     Enable BGP and enter BGP instance view.

bgp as-number [ instance instance-name ]

3.     Create the BGP IPv4 unicast address family and enter its view.

address-family ipv4 [ unicast ]

4.     Enable SR-MPLS.

segment-routing mpls

By default, SR-MPLS is disabled.

Configuring BGP prefix SIDs

About this task

To configure a BGP prefix SID, use the following methods:

·     Instead of specifying a routing policy for route redistribution, use the SID advertised by the IGP as the BGP prefix SID.

·     Specify a routing policy for route redistribution. Set the index value for the prefix SID in the routing policy to define the binding between the SID and the prefix.

Restrictions and guidelines

To use BGP routes to exchange prefix SIDs, you must enable BGP peers to exchange labeled routes.

Configuring the device to use the SIDs advertised by the IGP

1.     Configure the IGP to support SR-MPLS.

For more information, see "Configuring the IGP to support SR-MPLS."

2.     Configure prefix SIDs.

For more information, see "Configuring prefix SIDs."

3.     Enter system view.

system-view

4.     Enter BGP instance view.

bgp as-number [ instance instance-name ]

5.     Enter BGP IPv4 unicast address family view.

address-family ipv4 [ unicast ]

6.     Redistribute routes from IS-IS or OSPF.

import-route { isis | ospf } process-id

Specifying a routing policy for route redistribution

1.     Enter system view.

system-view

2.     Enter BGP instance view.

bgp as-number [ instance instance-name ]

3.     Enter BGP IPv4 unicast address family view.

address-family ipv4 [ unicast ]

4.     Redistribute routes from IS-IS or OSPF and apply a routing policy to the redistributed routes.

import-route { isis | ospf } process-id route-policy route-policy-name

5.     Set the index value for the prefix SID:

a.     Return to BGP instance view.

quit

b.     Return to system view.

quit

c.     Enter the routing policy view.

route-policy route-policy-name { deny | permit } node node-number

d.     Specify a label index value.

apply label-index index-value

By default, a routing policy does not have a label index value.

Configuring BGP EPE-based SID allocation

About this task

After you configure BGP EPE on a device, the device assigns SIDs to connected BGP peers or peer groups to identify the BGP neighbors or links.

Restrictions and guidelines

When you configure BGP EPE, follow these restrictions and guidelines:

·     By default, a BGP peering SID is node type.

·     If you do not specify a routing policy or an SID when enabling BGP EPE, the system will assign labels to BGP peers randomly.

·     BGP EPE must be deployed with SR-MPLS TE policy, MPLS TE tunnel, or static SRLSP. BGP EPE requires that the MPLS TE tunnel use a static SRLSP and the outgoing label of the static SRLSP must be the same as the label specified during BGP EPE configuration.

When you use BGP EPE to apply a routing policy to a peer or peer group, follow these restrictions and guidelines:

·     You cannot assign the same label to multiple BGP peers or peer groups.

·     You can specify the same routing policy to different BGP peers or peer groups only when you assign a Peer-Set-SID to the BGP peers or peer groups.

·     You can use if-match interface as a filtering condition only when assigning an adjacency SID to a BGP peer or peer group.

Procedure

1.     Enter system view.

system-view

2.     Enter BGP instance view.

bgp as-number [ instance instance-name ]

3.     Enable BGP EPE and specify a routing policy for the peer or peer group.

peer { group-name | ipv4-address [ mask-length ] } egress-engineering [ adjacency | set ] [ route-policy policy-name ]

By default, BGP EPE is disabled.

4.     Return to system view.

quit

5.     Enter the routing policy view.

route-policy route-policy-name { deny | permit } node node-number

6.     Specify a label value.

apply label-value label-value

By default, no label value is specified.

Configuring the SRLSP establishment triggering policy

About this task

To save system resources, you can configure the SRLSP establishment triggering policy to allow only certain FECs to trigger SRLSP establishment.

Procedure

1.     Enter system view.

system-view

2.     Enter OSPF view.

ospf process-id

3.     Enable BGP EPE and specify a routing policy for the peer or peer group.

segment-routing lsp-trigger { host | none | prefix-list prefix-name }

By default, the device allows all FECs to trigger SRLSP establishment.

 

Configuring the device to prefer SRLSPs in traffic forwarding

About this task

This feature enables the device to preferentially use SRLSPs to forward traffic when both SRLSPs and LDP LSPs are available for traffic forwarding. If you do not configure this feature, the device prefers to use LDP LSPs for traffic forwarding.

Restrictions and guidelines

This feature takes effect only when SR-MPLS is enabled and SRLSPs use prefix SIDs.

Configuring the device to prefer SRLSPs established by IS-IS in traffic forwarding

1.     Enter system view.

system-view

2.     Enter IS-IS view.

isis process-id

3.     Enter IS-IS IPv4 unicast address family view.

address-family ipv4

4.     Configure the device to prefer SRLSPs in traffic forwarding.

segment-routing sr-prefer [ prefix-list prefix-list-name ]

By default, the device prefers LDP LSPs to SRLSPs.

Configuring the device to prefer SRLSPs established by OSPF in traffic forwarding

5.     Enter system view.

system-view

6.     Enter OSPF view.

ospf process-id

7.     Configure the device to prefer SRLSPs in traffic forwarding.

segment-routing sr-prefer [ prefix-list prefix-list-name ]

By default, the device prefers LDP LSPs to SRLSPs.

 

Configuring an MPLS TE tunnel over a static SRLSP

Tasks at a glance

1.     Enable MPLS TE.

Perform this task on all nodes that the MPLS TE tunnel traverses. For more information, see MPLS TE configuration in MPLS Configuration Guide.

2.     Configuring a static SRLSP

Perform this task on the ingress node of the MPLS TE tunnel.

3.     Create the tunnel interface and specify the destination address of the tunnel.

Perform this task on the ingress node of the MPLS TE tunnel. For more information, see MPLS TE configuration in MPLS Configuration Guide.

4.     Binding a static SRLSP to an MPLS TE tunnel interface

Perform this task on the ingress node of the MPLS TE tunnel.

5.     Configure static routes or policy-based routing to direct traffic to the MPLS TE tunnel.

Perform this task on the ingress node of the MPLS TE tunnel. For more information, see MPLS TE configuration in MPLS Configuration Guide.

Configuring a static SRLSP

1.     Enter system view.

system-view

2.     Configure a static SRLSP.

static-sr-mpls lsp lsp-name out-label out-label-value&<1-15>

Binding a static SRLSP to an MPLS TE tunnel interface

1.     Enter system view.

system-view

2.     Enter MPLS TE tunnel interface view.

interface tunnel tunnel-number [ mode mpls-te ]

3.     Set the MPLS TE tunnel establishment mode to static.

mpls te signaling static

By default, MPLS TE uses RSVP-TE to establish a tunnel.

4.     Bind a static SRLSP to the MPLS TE tunnel interface.

mpls te static-sr-mpls lsp-name

By default, an MPLS TE tunnel does not use a static SRLSP.

Configuring an MPLS TE tunnel over an explicit-path SRLSP

Tasks at a glance

Perform the following tasks on the ingress node of the MPLS TE tunnel:

1.     Configuring an explicit path for the MPLS TE tunnel

2.     Creating an MPLS TE tunnel interface and specifying the destination address.

For more information, see MPLS TE configuration in MPLS Configuration Guide.

3.     Configuring an MPLS TE tunnel over the explicit path

Prerequisites

Before you configure an MPLS TE tunnel over an explicit-path SRLSP, perform the following tasks:

·     Determine the ingress node of the SRLSP.

·     Determine the SIDs of the nodes along the SRLSP.

·     Enable MPLS on all nodes and interfaces that will participate in MPLS forwarding. For information about enabling MPLS, see basic MPLS configuration in MPLS Configuration Guide.

Configuring an explicit path for the MPLS TE tunnel

1.     Enter system view.

system-view

2.     Create an explicit path and enter its view.

explicit-path path-name

3.     Add or modify a node in the explicit path.

¡     Specify a node by its label.

nextsid [ index index-number ] label label-value type { adjacency | prefix }

¡     Specify a node by its IP address.

nexthop [ index index-number ] ip-address [ exclude | include [ loose | strict ] ]

By default, an explicit path does not include any node.

Configuring an MPLS TE tunnel over the explicit path

1.     Enter system view.

system-view

2.     Enter MPLS TE tunnel interface view.

interface tunnel tunnel-number mode mpls-te

3.     Set the MPLS TE tunnel establishment mode to SR.

mpls te signaling segment-routing

By default, MPLS TE uses RSVP-TE to establish a tunnel.

4.     Configure the MPLS TE tunnel interface to use an explicit path.

mpls te path preference value explicit-path path-name [ no-cspf ]

By default, MPLS TE uses the calculated path to establish an SRLSP.

You must specify the no-cspf keyword if the specified explicit path is established by using the nextsid command, the path contains an adjacency SID, and the adjacency SID exists on multiple interfaces.

5.     (Optional.) Configure the tunnel interface to perform CSPF calculation strictly based on adjacency SID information when establishing an SRLSP for an MPLS TE tunnel.

mpls te path-selection adjacency-sid

By default, a tunnel interface does not perform CSPF calculation strictly based on adjacency SID information when establishing an SRLSP for an MPLS TE tunnel.

Configuring an MPLS TE tunnel over a PCE-calculated SRLSP

Tasks at a glance

1.     Enabling MPLS TE

Perform this task on all nodes that the MPLS TE tunnel traverses. For more information, see MPLS TE configuration in MPLS Configuration Guide.

2.     Configuring PCE discovery

Perform this task on all nodes that the MPLS TE tunnel traverses. You can manually specify PCEs or configure dynamic PCE discovery (OSPF TE). For more information, see MPLS TE configuration in MPLS Configuration Guide.

3.     Establishing a PCEP session that supports SR.

Perform this task on all nodes that the MPLS TE tunnel traverses. Set the PCEP device type to active stateful. For more information, see MPLS TE configuration in MPLS Configuration Guide.

4.     Creating an MPLS TE tunnel interface and specifying the destination address.

Perform this task on the ingress node of the MPLS TE tunnel. For more information, see MPLS TE configuration in MPLS Configuration Guide.

5.     Configuring an MPLS TE tunnel interface to use PCE to calculate the SRLSP

Perform this task on the ingress node of the MPLS TE tunnel.

Configuring an MPLS TE tunnel interface to use PCE to calculate the SRLSP

1.     Enter system view.

system-view

2.     Enter MPLS TE tunnel interface view.

interface tunnel tunnel-number mode mpls-te

3.     Set the MPLS TE tunnel establishment mode to SR.

mpls te signaling segment-routing

By default, MPLS TE uses RSVP-TE to establish a tunnel.

4.     Configure the MPLS TE tunnel interface to use PCE to calculate the SRLSP.

¡     Establish an SRLSP by using the path calculated by PCEs.

mpls te path preference value dynamic [ pce [ ip-address ]&<0-8> ]

By default, the automatically calculated path is used to establish an SRLSP.

¡     Establish an SRLSP by using SRLSP delegation.

mpls te delegation

By default, SRLSP delegation is disabled.

Configuring IGP SR and LDP interworking

Restrictions and guidelines for IGP SR and LDP interworking

To configure IGP SR and LDP interworking, make sure the SRLSP uses prefix SIDs.

SR to LDP tasks at a glance

SRMS tasks at a glance

Perform the following tasks on an SRMS:

1.     Enabling SR-MPLS on the SRMS:

a.     Configuring the IGP to support SR-MPLS

b.     Configuring prefix SIDs

c.     Configuring MPLS SRGBs

d.     Enabling advertisement of locally configured prefix-SID mappings

2.     Configuring prefix-SID mappings

SRMC tasks at a glance

Perform the following tasks on each SRMC:

1.     Enabling SR-MPLS on the SRMC:

a.     Configuring the IGP to support SR-MPLS

b.     Configuring prefix SIDs

c.     Configuring MPLS SRGBs

2.     Enabling reception of advertised prefix-SID mappings

LDP to SR tasks at a glance

1.     Configuring the IGP to support SR-MPLS

2.     Configuring prefix SIDs

3.     Configuring MPLS SRGBs

SR over LDP tasks at a glance

1.     Configuring the IGP to support SR-MPLS

2.     Configuring prefix SIDs

3.     Configuring MPLS SRGBs

Prerequisites for SR-MPLS and LDP internetworking

Before you configure SR-MPLS and LDP internetworking, perform the following tasks:

·     Determine the ingress node, transit nodes, and egress node of an SRLSP.

·     Determine the index value for the prefix SID of each node.

·     Enable MPLS on all nodes and interfaces that will participate in MPLS forwarding. For information about enabling MPLS, see basic MPLS configuration in MPLS Configuration Guide.

Enabling advertisement of locally configured prefix-SID mappings

Restrictions and guidelines

Configure this feature on the device that acts as the SRMS.

Configuring IS-IS to advertise locally configured prefix-SID mappings

1.     Enter system view.

system-view

2.     Enter IS-IS view.

isis process-id

3.     Enter IS-IS IPv4 unicast address family view.

address-family ipv4

4.     Enable advertisement of locally configured prefix-SID mappings.

segment-routing mapping-server advertise-local

By default, advertisement is disabled for locally configured prefix-SID mappings.

Configuring OSPF to advertise locally configured prefix-SID mappings

1.     Enter system view.

system-view

2.     Enter OSPF view.

ospf process-id

3.     Enable advertisement of locally configured prefix-SID mappings.

segment-routing mapping-server advertise-local

By default, advertisement is disabled for locally configured prefix-SID mappings.

Configuring prefix-SID mappings

Restrictions and guidelines

Configure this feature on the device that acts as the SRMS.

The specified prefixes must not belong to any existing prefix-SID mappings.

Prerequisites

Before you configure prefix-SID mappings in bulk, plan the number of mappings carefully.

Procedure

1.     Enter system view.

system-view

2.     Enable SR and enter segment routing view.

segment-routing

3.     Configure a prefix-SID mapping.

mapping-server prefix-sid-map ip-address mask-length start-value [ range range-value ] [ attached ]

By default, no prefix-SID mappings exist.

If you specify a value greater than 65535 for the range-value argument, the prefix-SID mappings cannot be advertised through IS-IS or OSPF.

Enabling reception of advertised prefix-SID mappings

Restrictions and guidelines

Configure this feature on the devices that act as the SRMCs.

Configuring IS-IS to receive advertised prefix-SID mappings

1.     Enter system view.

system-view

2.     Enter IS-IS view.

isis process-id

3.     Enter IS-IS IPv4 unicast address family view.

address-family ipv4

4.     Enable reception of prefix-SID mappings.

segment-routing mapping-server receive

By default, reception of prefix-SID mappings is enabled.

Configuring OSPF to receive advertised prefix-SID mappings

1.     Enter system view.

system-view

2.     Enter OSPF view.

ospf process-id

3.     Enable reception of prefix-SID mappings.

segment-routing mapping-server receive

By default, reception of prefix-SID mappings is enabled.

Configuring TI-LFA FRR

Restrictions and guidelines for TI-LFA FRR

TI-LFA FRR is not supported on static SR networks.

In SR-MPLS and LDP interworking scenarios, you must configure the device to prefer the IS-IS or OSPF SRLSP to the LDP LSP. This rule ensures the effectiveness of the TI-LFA FRR backup next hop.

TI-LFA FRR tasks at a glance

1.     Enabling TI-LFA FRR

2.     (Optional.) Disabling an interface from participating in TI-LFA calculation

On the source node, disable TI-LFA on the route's output interface to the next hop on the primary path.

3.     (Optional.) Configuring microloop avoidance

Enabling TI-LFA FRR

Enabling TI-LFA FRR for IS-IS

1.     Enter system view.

system-view

2.     Enter IS-IS view.

isis process-id

3.     Enter IS-IS IPv4 unicast address family view.

address-family ipv4

4.     Enable LFA FRR for IS-IS.

fast-reroute lfa [ level-1 | level-2 ]

By default, LFA FRR is disabled for IS-IS.

5.     Enable TI-LFA FRR for IS-IS.

fast-reroute ti-lfa [ per-prefix ] [ route-policy route-policy-name | host ] [ level-1 | level-2 ]

By default, TI-LFA FRR is disabled for IS-IS.

Enabling TI-LFA FRR for OSPF

1.     Enter system view.

system-view

2.     Enter OSPF view.

ospf process-id

3.     Enable LFA FRR for OSPF.

fast-reroute { lfa [ abr-only ] | route-policy route-policy-name }

By default, LFA FRR is disabled for OSPF.

4.     Enable TI-LFA FRR for OSPF.

fast-reroute ti-lfa [ per-prefix ] [ route-policy route-policy-name | host ]

By default, TI-LFA FRR is disabled for OSPF.

 

Disabling an interface from participating in TI-LFA calculation

Disabling an IS-IS interface from participating in TI-LFA calculation

1.     Enter system view.

system-view

2.     Enter the view of IS-IS interface.

interface interface-type interface-number

3.     Disable the interface from participating in TI-LFA calculation.

isis fast-reroute ti-lfa disable [ level-1 | level-2 ]

By default, an IS-IS interface participates in TI-LFA calculation.

Disabling an OSPF interface from participating in TI-LFA calculation

1.     Enter system view.

system-view

2.     Enter the view of OSPF interface.

interface interface-type interface-number

3.     Disable the interface from participating in TI-LFA calculation.

ospf fast-reroute ti-lfa disable

By default, an OSPF interface participates in TI-LFA calculation.

 

Configuring microloop avoidance

About this task

The following microloop avoidance methods are available:

·     FRR microloop avoidance—Provides microloop avoidance after a network failure.

On a network deployed with TI-LFA FRR, when a node or link fails, traffic will be switched to the backup path calculated by TI-LFA. If devices on the backup path have not finished route convergence, a loop is formed between the source node (failed node or the previous node along the link) and a device on the backup path. The loop exists until the devices on the backup path finish route convergence.

To resolve this issue, FRR microloop avoidance first switches traffic to the backup path calculated by TI-LFA after the node or link failure. Then, the source node waits for the nodes on the backup path to finish route convergence before starting route convergence.

·     SR microloop avoidance—Provides microloop avoidance both after a network failure and after a failure recovery.

After a network failure occurs or recovers, route convergence occurs on relevant network devices. Because of non-simultaneous convergence on network devices, microloops might be formed. After you configure SR microloop avoidance, the devices will forward traffic along the specified path before route convergence is finished on all the relevant network devices. Because the forwarding path is independent of route convergence, microloops are avoided.

To leave sufficient time for IGP to finish route convergence, set the SR microloop avoidance RIB-update-delay timer. Before the timer expires, failure relevant devices will forward traffic along the specified path. After the timer expires, IGP route convergence should have finished and traffic will traverse along the IGP-calculated path.

Restrictions and guidelines

If you configure both FRR microloop avoidance and SR microloop avoidance, SR microloop avoidance takes effect.

Configuring FRR microloop avoidance for IS-IS

1.     Enter system view.

system-view

2.     Enter IS-IS view.

isis process-id

3.     Enter IS-IS IPv4 unicast address family view.

address-family ipv4

4.     Enable FRR microloop avoidance for IS-IS.

fast-reroute microloop-avoidance enable [ level-1 | level-2 ]

By default, FRR microloop avoidance is disabled for IS-IS.

5.     (Optional.) Set the FRR microloop avoidance RIB-update-delay time.

fast-reroute microloop-avoidance rib-update-delay delay-time [ level-1 | level-2 ]

By default, the FRR microloop avoidance RIB-update-delay time is 5000 ms.

Configuring FRR microloop avoidance for OSPF

1.     Enter system view.

system-view

2.     Enter OSPF view.

ospf process-id

3.     Enable FRR microloop avoidance for OSPF.

fast-reroute microloop-avoidance enable

By default, FRR microloop avoidance is disabled for OSPF.

4.     (Optional.) Set the FRR microloop avoidance RIB-update-delay time.

fast-reroute microloop-avoidance rib-update-delay delay-time

By default, the FRR microloop avoidance RIB-update-delay time is 5000 ms.

 

Configuring SR microloop avoidance for IS-IS

1.     Enter system view.

system-view

2.     Enter IS-IS view.

isis process-id

3.     Enter IS-IS IPv4 unicast address family view.

address-family ipv4

4.     Enable SR microloop avoidance for IS-IS.

segment-routing microloop-avoidance enable [ level-1 | level-2 ]

By default, SR microloop avoidance is disabled for IS-IS.

5.     (Optional.) Set the SR microloop avoidance RIB-update-delay time.

segment-routing microloop-avoidance rib-update-delay delay-time [ level-1 | level-2 ]

By default, the SR microloop avoidance RIB-update-delay time is 5000 ms.

Configuring SR microloop avoidance for OSPF

1.     Enter system view.

system-view

2.     Enter OSPF view.

ospf process-id

3.     Enable SR microloop avoidance for OSPF.

segment-routing microloop-avoidance enable

By default, SR microloop avoidance is disabled for OSPF.

4.     (Optional.) Set the SR microloop avoidance RIB-update-delay time for OSPF.

segment-routing microloop-avoidance rib-update-delay delay-time

By default, the SR microloop avoidance RIB-update-delay time is 5000 ms.

 

Verifying and maintaining MPLS SR

Displaying SR label block information

Perform display tasks in any view.

·     Display SR-MPLS label block information.

display segment-routing label–block [ protocol { isis | ospf } ]

·     Display prefix-SID mappings.

display segment-routing mapping-server prefix-sid-map [ ip-address mask-length | verbose ]

Displaying static segments

Perform display tasks in any view.

·     Display static SRLSP information.

display mpls static-sr-mpls lsp [ lsp-name ]

·     Display static adjacency segment information.

display mpls static-sr-mpls adjacency [ adjacency-path-name ]

·     Display static prefix segment information.

display mpls static-sr-mpls prefix [ path prefix-path-name | destination ip-address [ mask | mask-length ] ]

Displaying BGP SR configuration and status information

Perform display tasks in any view.

·     Display BGP-EPE segment information.

display bgp [ instance instance-name ] egress-engineering ipv4 [ ipv4-address ]

·     Display BGP SR label ranges.

display bgp [ instance instance-name ] segment-routing label-range

Displaying IS-IS SR configuration and status information

Perform display tasks in any view.

·     Display IS-IS SRGB information.

display isis segment-routing global-block [ level-1 | level-2 ] [ process-id ]

·     Display IS-IS SR adjacency segment information.

display isis [ process-id ] segment-routing adjacency [ { member-port | non-member-port } | sid sid-value | vpn-instance vpn-instance-name ] *

·     Display IS-IS SR prefix-SID mappings.

display isis segment-routing prefix-sid-map [ active-policy | backup-policy ] [ process-id ] [ verbose ]

Displaying OSPF SR configuration and status information

Perform display tasks in any view.

·     Display OSPF SRGB information.

display ospf [ process-id ] [ area area-id ] segment-routing global-block

·     Display OSPF SR adjacency segment information.

display ospf [ process-id ] segment-routing adjacency [ sid sid-value ] [ vpn-instance vpn-instance-name ]

·     Display OSPF SR prefix-SID mappings.

display ospf segment-routing prefix-sid-map [ active-policy | backup-policy ] [ process-id ] [ verbose ]

SR-MPLS configuration examples

Example: Configuring SR-MPLS based on static segments

Network configuration

As shown in Figure 17, Router A, Router B, Router C, Router D, and Router E run IS-IS.

Establish an MPLS TE tunnel over a static SRLSP from Router A to Router D to transmit data between the IP networks. The static SRLSP traverses three adjacency segments: Router A—Router B, Router B—Router C, and Router C—Router D.

Establish an MPLS TE tunnel over a static SRLSP from Router A to Router E to transmit data between the IP networks. The static SRLSP traverses three segments: Router A—Router B (adjacency segment), Router B—Router C (prefix segment), and Router C—Router E (adjacency segment).

Figure 17 Network diagram

Table 1 Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

Router A

Loop0

1.1.1.9/32

Router B

Loop0

2.2.2.9/32

 

HGE1/0/1

100.1.1.1/24

 

HGE1/0/1

10.1.1.2/24

 

HGE1/0/2

10.1.1.1/24

 

HGE1/0/2

20.1.1.1/24

 

 

 

 

HGE1/0/3

60.1.1.1/24

Router C

Loop0

3.3.3.9/32

Router D

Loop0

4.4.4.9/32

 

HGE1/0/1

30.1.1.1/24

 

HGE1/0/1

100.1.2.1/24

 

HGE1/0/2

20.1.1.2/24

 

HGE1/0/2

30.1.1.2/24

 

HGE1/0/3

50.1.1.1/24

 

 

 

 

HGE1/0/4

60.1.1.2/24

 

 

 

Router E

Loop0

5.5.5.9/32

 

 

 

 

HGE1/0/1

200.1.2.1/24

 

 

 

 

HGE1/0/2

50.1.1.2/24

 

 

 

 

Prerequisites

1.     Configure IP addresses and masks for interfaces.

2.     Configure IS-IS to advertise interface addresses, including the loopback interface address.

3.     Execute the display ip routing-table command on each router to verify that the routers have learned the routes to one another, including the routes to the loopback interfaces.

4.     By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

Procedure

5.     Configure LSR IDs, and enable MPLS and MPLS TE:

# Configure Router A.

<RouterA> system-view

[RouterA] mpls lsr-id 1.1.1.9

[RouterA] mpls te

[RouterA-te] quit

[RouterA] interface hundredgige 1/0/2

[RouterA-HundredGigE1/0/2] mpls enable

[RouterA-HundredGigE1/0/2] quit

# Configure Router B.

<RouterB> system-view

[RouterB] mpls lsr-id 2.2.2.9

[RouterB] mpls te

[RouterB-te] quit

[RouterB] interface hundredgige 1/0/1

[RouterB-HundredGigE1/0/1] mpls enable

[RouterB-HundredGigE1/0/1] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] mpls enable

[RouterB-HundredGigE1/0/2] quit

[RouterB] interface hundredgige 1/0/3

[RouterB-HundredGigE1/0/3] mpls enable

[RouterB-HundredGigE1/0/3] quit

# Configure Router C.

<RouterC> system-view

[RouterC] mpls lsr-id 3.3.3.9

[RouterC] mpls te

[RouterC-te] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] mpls enable

[RouterC-HundredGigE1/0/1] quit

[RouterC] interface hundredgige 1/0/2

[RouterC-HundredGigE1/0/2] mpls enable

[RouterC-HundredGigE1/0/2] quit

[RouterC] interface hundredgige 1/0/3

[RouterC-HundredGigE1/0/3] mpls enable

[RouterC-HundredGigE1/0/3] quit

[RouterC] interface hundredgige 1/0/4

[RouterC-HundredGigE1/0/4] mpls enable

[RouterC-HundredGigE1/0/4] quit

# Configure Router D.

<RouterD> system-view

[RouterD] mpls lsr-id 4.4.4.9

[RouterD] mpls te

[RouterD-te] quit

[RouterD] interface hundredgige 1/0/2

[RouterD-HundredGigE1/0/2] mpls enable

[RouterD-HundredGigE1/0/2] quit

# Configure Router E.

<RouterE> system-view

[RouterE] mpls lsr-id 5.5.5.9

[RouterE] mpls te

[RouterE-te] quit

[RouterE] interface hundredgige 1/0/2

[RouterE-HundredGigE1/0/2] mpls enable

[RouterE-HundredGigE1/0/2] quit

6.     Configure adjacency and prefix segments on the nodes:

# On Router A, create adjacency segment adjacency-1, and bind incoming label 16 to next hop address 10.1.1.2.

[RouterA] static-sr-mpls adjacency adjacency-1 in-label 16 nexthop 10.1.1.2

# On Router B, create adjacency segment adjacency-2, and bind incoming label 21 to next hop address 20.1.1.2.

[RouterB] static-sr-mpls adjacency adjacency-2 in-label 21 nexthop 20.1.1.2

# On Router B, create prefix segments named prefix-1 to destination IP address 5.5.5.9, bind incoming label 16000 to next hop addresses 20.1.1.2 and 60.1.1.2, and specify the outgoing label as 16001.

[RouterB] static-sr-mpls prefix prefix-1 destination 5.5.5.9 32 in-label 16000 nexthop 20.1.1.2 out-label 16001

[RouterB] static-sr-mpls prefix prefix-1 destination 5.5.5.9 32 in-label 16000 nexthop 60.1.1.2 out-label 16001

# On Router C, create adjacency segment adjacency-1, and bind incoming label 30 to next hop address 30.1.1.2. Create adjacency segment adjacency-2, and bind incoming label 31 to next hop address 50.1.1.2.

[RouterC] static-sr-mpls adjacency adjacency-1 in-label 30 nexthop 30.1.1.2

[RouterC] static-sr-mpls adjacency adjacency-2 in-label 31 nexthop 50.1.1.2

# On Router C, create prefix segment named prefix-1 to destination IP address 5.5.5.9, and specify the incoming label as 16001.

[RouterC] static-sr-mpls prefix prefix-1 destination 5.5.5.9 32 in-label 16001

7.     On Router A, establish static SRLSP static-sr-lsp-1 to Router D and static SRLSP static-sr-lsp-2 to Router E:

# Configure Router A as the ingress node of static SRLSP static-sr-lsp-1 and configure a label stack of [16, 21, 30].

[RouterA] static-sr-mpls lsp static-sr-lsp-1 out-label 16 21 30

# Configure Router A as the ingress node of static SRLSP static-sr-lsp-2 and configure a label stack of [16, 16000, 31].

[RouterA] static-sr-mpls lsp static-sr-lsp-2 out-label 16 16000 31

8.     Configure MPLS TE tunnels over static SRLSPs on Router A:

# Establish static MPLS TE tunnel 0 to Router D and specify the tunnel destination address as the LSR ID of Router D. Bind static SRLSP static-sr-lsp-1 to MPLS TE tunnel interface 0.

[RouterA] interface tunnel 0 mode mpls-te

[RouterA-Tunnel0] ip address 6.1.1.1 255.255.255.0

[RouterA-Tunnel0] destination 4.4.4.9

[RouterA-Tunnel0] mpls te signaling static

[RouterA-Tunnel0] mpls te static-sr-mpls static-sr-lsp-1

[RouterA-Tunnel0] quit

# Establish static MPLS TE tunnel 1 to Router E and specify the tunnel destination address as the LSR ID of Router E. Bind static SRLSP static-sr-lsp-2 to MPLS TE tunnel interface 1.

[RouterA] interface tunnel 1 mode mpls-te

[RouterA-Tunnel1] ip address 7.1.1.1 255.255.255.0

[RouterA-Tunnel1] destination 5.5.5.9

[RouterA-Tunnel1] mpls te signaling static

[RouterA-Tunnel1] mpls te static-sr-mpls static-sr-lsp-2

[RouterA-Tunnel1] quit

9.     On Router A, configure two static routes to direct traffic destined for 100.1.2.0/24 and 200.1.2.0/24 to MPLS TE tunnel 0 and tunnel 1, respectively.

[RouterA] ip route-static 100.1.2.0 24 tunnel 0 preference 1

[RouterA] ip route-static 200.1.2.0 24 tunnel 1 preference 1

Verifying the configuration

# Display the MPLS TE tunnel information on Router A.

[RouterA] display mpls te tunnel-interface

Tunnel Name            : Tunnel 0

Tunnel State           : Up (Main CRLSP up)

Tunnel Attributes      :

  LSP ID               : 1               Tunnel ID            : 0

  Admin State          : Normal

  Ingress LSR ID       : 1.1.1.9         Egress LSR ID        : 4.4.4.9

  Signaling            : Static          Static CRLSP Name    : -

  Static SRLSP Name    : static-sr-lsp-1/-

  Resv Style           : -

  Tunnel mode          : -

  Reverse-LSP name     : -

  Reverse-LSP LSR ID   : -               Reverse-LSP Tunnel ID: -

  Class Type           : -               Tunnel Bandwidth     : -

  Reserved Bandwidth   : -

  Setup Priority       : 0               Holding Priority     : 0

  Affinity Attr/Mask   : -/-

  Explicit Path        : -

  Backup Explicit Path : -

  Metric Type          : TE

  Record Route         : -               Record Label         : -

  FRR Flag             : -               Backup Bandwidth Flag: -

  Backup Bandwidth Type: -               Backup Bandwidth     : -

  Route Pinning        : -

  Retry Limit          : 3               Retry Interval       : 2 sec

  Reoptimization       : -               Reoptimization Freq  : -

  Backup Type          : -               Backup LSP ID        : -

  Auto Bandwidth       : -               Auto Bandwidth Freq  : -

  Min Bandwidth        : -               Max Bandwidth        : -

  Collected Bandwidth  : -

 

Tunnel Name            : Tunnel 1

Tunnel State           : Up (Main CRLSP up)

Tunnel Attributes      :

  LSP ID               : 1               Tunnel ID            : 0

  Admin State          : Normal

  Ingress LSR ID       : 1.1.1.9         Egress LSR ID        : 5.5.5.9

  Signaling            : Static          Static CRLSP Name    : -

  Static SRLSP Name    : static-sr-lsp-2/-

  Resv Style           : -

  Tunnel mode          : -

  Reverse-LSP name     : -

  Reverse-LSP LSR ID   : -               Reverse-LSP Tunnel ID: -

  Class Type           : -               Tunnel Bandwidth     : -

  Reserved Bandwidth   : -

  Setup Priority       : 0               Holding Priority     : 0

  Affinity Attr/Mask   : -/-

  Explicit Path        : -

  Backup Explicit Path : -

  Metric Type          : TE

  Record Route         : -               Record Label         : -

  FRR Flag             : -               Bandwidth Protection : -

  Backup Bandwidth Flag: -               Backup Bandwidth Type: -

  Backup Bandwidth     : -

  Bypass Tunnel        : -               Auto Created         : -

  Route Pinning        : -

  Retry Limit          : 3               Retry Interval       : 2 sec

  Reoptimization       : -               Reoptimization Freq  : -

  Backup Type          : -               Backup LSP ID        : -

  Auto Bandwidth       : -               Auto Bandwidth Freq  : -

  Min Bandwidth        : -               Max Bandwidth        : -

  Collected Bandwidth  : -

# Display static SRLSP establishment on each router by using the display mpls lsp or display mpls static-sr-lsp command.

[RouterA] display mpls lsp

FEC                         Proto    In/Out Label    Out Inter/NHLFE/LSINDEX

1.1.1.9/0/1                 StaticCR -/21            HGE1/0/1

                                       30

1.1.1.9/1/2                 StaticCR -/16000         HGE1/0/1

                                       31

[RouterB] display mpls lsp

FEC                         Proto    In/Out Label    Out Inter/NHLFE/LSINDEX

-                           StaticCR 21/-            HGE1/0/2

5.5.5.9/32                  StaticCR 16000/16001     HGE1/0/2

5.5.5.9/32                  StaticCR 16000/16001     HGE1/0/4

 

[RouterC] display mpls lsp

FEC                         Proto    In/Out Label    Out Inter/NHLFE/LSINDEX

-                           StaticCR 30/-            HGE1/0/1

-                           StaticCR 31/-            HGE1/0/3

5.5.5.9/32                  StaticCR 16001/-          -

Example: Configuring SR-MPLS based on ISIS-advertised SIDs

Network configuration

As shown in Figure 18, Router A, Router B, Router C, and Router D are running IS-IS.

Configure dynamic SID allocation on loopback interfaces of the routers. Then, establish an SRLSP from Router A to Router D based on the allocated SIDs and configure an MPLS TE tunnel over the SRLSP to transmit data.

Figure 18 Network diagram

Table 2 Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

Router A

Loop1

1.1.1.1/32

Router B

Loop1

2.2.2.2/32

 

HGE1/0/1

10.0.0.1/24

 

HGE1/0/1

10.0.0.2/24

 

 

 

 

HGE1/0/2

11.0.0.1/24

Router C

Loop1

3.3.3.3/32

Router D

Loop1

4.4.4.4/32

 

HGE1/0/1

11.0.0.2/24

 

HGE1/0/1

12.0.0.2/24

 

HGE1/0/2

12.0.0.1/24

 

HGE1/0/2

100.1.2.1/24

 

Prerequisites

Configure IP addresses and masks for interfaces.

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

Procedure

1.     Configure IS-IS on the routers and set the IS-IS cost style to wide:

# Configure Router A.

<RouterA> system-view

[RouterA] isis 1

[RouterA-isis-1] network-entity 00.0000.0000.0001.00

[RouterA-isis-1] cost-style wide

[RouterA-isis-1] quit

[RouterA] interface hundredgige 1/0/1

[RouterA-HundredGigE1/0/1] isis enable 1

[RouterA-HundredGigE1/0/1] quit

[RouterA] interface loopback 1

[RouterA-LoopBack1] isis enable 1

[RouterA-LoopBack1] quit

# Configure Router B.

<RouterB> system-view

[RouterB] isis 1

[RouterB-isis-1] network-entity 00.0000.0000.0002.00

[RouterB-isis-1] cost-style wide

[RouterB-isis-1] quit

[RouterB] interface hundredgige 1/0/1

[RouterB-HundredGigE1/0/1] isis enable 1

[RouterB-HundredGigE1/0/1] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] isis enable 1

[RouterB-HundredGigE1/0/2] quit

[RouterB] interface loopback 1

[RouterB-LoopBack1] isis enable 1

[RouterB-LoopBack1] quit

# Configure Router C.

<RouterC> system-view

[RouterC] isis 1

[RouterC-isis-1] network-entity 00.0000.0000.0003.00

[RouterC-isis-1] cost-style wide

[RouterC-isis-1] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] isis enable 1

[RouterC-HundredGigE1/0/1] quit

[RouterC] interface hundredgige 1/0/2

[RouterC-HundredGigE1/0/2] isis enable 1

[RouterC-HundredGigE1/0/2] quit

[RouterC] interface loopback 1

[RouterC-LoopBack1] isis enable 1

[RouterC-LoopBack1] quit

# Configure Router D.

<RouterD> system-view

[RouterD] isis 1

[RouterD-isis-1] network-entity 00.0000.0000.0004.00

[RouterD-isis-1] cost-style wide

[RouterD-isis-1] quit

[RouterD] interface hundredgige 1/0/1

[RouterD-HundredGigE1/0/1] isis enable 1

[RouterD-HundredGigE1/0/1] quit

[RouterD] interface hundredgige 1/0/2

[RouterD-HundredGigE1/0/2] isis enable 1

[RouterD-HundredGigE1/0/2] quit

[RouterD] interface loopback 1

[RouterD-LoopBack1] isis enable 1

[RouterD-LoopBack1] quit

2.     Configure LSR IDs, and enable MPLS and MPLS TE on the routers:

# Configure Router A.

[RouterA] mpls lsr-id 1.1.1.1

[RouterA] mpls te

[RouterA-te] quit

[RouterA] interface hundredgige 1/0/1

[RouterA-HundredGigE1/0/1] mpls enable

[RouterA-HundredGigE1/0/1] quit

# Configure Router B.

[RouterB] mpls lsr-id 2.2.2.2

[RouterB] mpls te

[RouterB-te] quit

[RouterB] interface hundredgige 1/0/1

[RouterB-HundredGigE1/0/1] mpls enable

[RouterB-HundredGigE1/0/1] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] mpls enable

[RouterB-HundredGigE1/0/2] quit

# Configure Router C.

[RouterC] mpls lsr-id 3.3.3.3

[RouterC] mpls te

[RouterC-te] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] mpls enable

[RouterC-HundredGigE1/0/1] quit

[RouterC] interface hundredgige 1/0/2

[RouterC-HundredGigE1/0/2] mpls enable

[RouterC-HundredGigE1/0/2] quit

# Configure Router D.

[RouterD] mpls lsr-id 4.4.4.4

[RouterD] mpls te

[RouterD-te] quit

[RouterD] interface hundredgige 1/0/1

[RouterD-HundredGigE1/0/1] mpls enable

[RouterD-HundredGigE1/0/1] quit

3.     Configure SRGBs and enable SR-MPLS on the routers:

# Configure Router A.

[RouterA] isis 1

[RouterA-isis-1] segment-routing global-block 16000 16999

[RouterA-isis-1] address-family ipv4

[RouterA-isis-1-ipv4] segment-routing mpls

[RouterA-isis-1-ipv4] quit

[RouterA-isis-1] quit

# Configure Router B.

[RouterB] isis 1

[RouterB-isis-1] segment-routing global-block 17000 17999

[RouterB-isis-1] address-family ipv4

[RouterB-isis-1-ipv4] segment-routing mpls

[RouterB-isis-1-ipv4] quit

[RouterB-isis-1] quit

# Configure Router C.

[RouterC] isis 1

[RouterC-isis-1] segment-routing global-block 18000 18999

[RouterC-isis-1] address-family ipv4

[RouterC-isis-1-ipv4] segment-routing mpls

[RouterC-isis-1-ipv4] quit

[RouterC-isis-1] quit

# Configure Router D.

[RouterD] isis 1

[RouterD-isis-1] segment-routing global-block 19000 19999

[RouterD-isis-1] address-family ipv4

[RouterD-isis-1-ipv4] segment-routing mpls

[RouterD-isis-1-ipv4] quit

[RouterD-isis-1] quit

4.     Configure IS-IS prefix SIDs for the routers:

# Configure Router A.

[RouterA] interface loopback 1

[RouterA-LoopBack1] isis prefix-sid index 10

# Configure Router B.

[RouterB] interface loopback 1

[RouterB-LoopBack1] isis prefix-sid index 20

# Configure Router C.

[RouterC] interface loopback 1

[RouterC-LoopBack1] isis prefix-sid index 30

# Configure Router D.

[RouterD] interface loopback 1

[RouterD-LoopBack1] isis prefix-sid index 40

5.     On Router A, establish static SRLSP static-sr-lsp-1 to Router D and configure an MPLS TE tunnel over the static SRLSP:

# Configure Router A as the ingress node of static SRLSP static-sr-lsp-1 and specify the prefix label that Router A allocated to Router D (16040) as the outgoing label.

[RouterA] static-sr-mpls lsp static-sr-lsp-1 out-label 16040

# Establish static MPLS TE tunnel 1 to Router D and specify the LSR ID of Router D as the tunnel destination address. Bind static SRLSP static-sr-lsp-1 to MPLS TE tunnel interface 1.

[RouterA] interface tunnel 1 mode mpls-te

[RouterA-Tunnel1] ip address 6.1.1.1 255.255.255.0

[RouterA-Tunnel1] destination 4.4.4.4

[RouterA-Tunnel1] mpls te signaling static

[RouterA-Tunnel1] mpls te static-sr-mpls static-sr-lsp-1

[RouterA-Tunnel1] quit

6.     On Router A, configure a static route to direct traffic destined for 100.1.2.0/24 to MPLS TE tunnel 1.

[RouterA] ip route-static 100.1.2.0 24 tunnel 1 preference 1

Verifying the configuration

# Display IS-IS process information on Router A.

[RouterA] display isis

 

           IS-IS(1) Protocol Information

 

Network entity                  : 00.0000.0000.0001.00

IS level                        : level-1

Cost style                      : Wide

Fast reroute                    : Disabled

Preference                      : 15

LSP length receive              : 1497

LSP length originate

    level-1                     : 1497

Maximum imported routes         : 100000

Timers

    LSP-max-age                 : 1200

    LSP-refresh                 : 900

    SPF mode                    : Normal

    SPF intervals               : 5 50 200

Segment routing

    MPLS                        : Enabled

    Adjacency                   : Disabled

    global block                : 16000 16999

# Display detailed IS-IS interface information on Router A to view SID information for the loopback interface.

[RouterA] display isis interface verbose

 

                       Interface information for IS-IS(1)

                       ----------------------------------

  Interface:  LoopBack1

  Index     IPv4 state      IPv6 state     Circuit ID   MTU   Type   DIS

  00002     Up              Down           1            1536  L1/L2  --

  SNPA address                     : 0000-0000-0000

  IP address                       : 1.1.1.1

  Secondary IP address(es)         :

  IPv6 link-local address          :

  Extended circuit ID              : 2

  CSNP timer value                 : L1        10  L2        10

  Hello timer value                :           10

  Hello multiplier value           :            3

  LSP timer value                  : L12       33

  LSP transmit-throttle count      : L12        5

  Cost                             : L1         0  L2         0

  IPv6 cost                        : L1         0  L2         0

  Priority                         : L1        64  L2        64

  Retransmit timer value           : L12        5

  MPLS TE status                   : L1  Disabled  L2  Disabled

  IPv4 BFD                         : Disabled

  IPv6 BFD                         : Disabled

  IPv4 FRR LFA backup              : Enabled

  IPv6 FRR LFA backup              : Enabled

  IPv4 prefix suppression          : Disabled

  IPv6 prefix suppression          : Disabled

  IPv4 tag                         : 0

  IPv6 tag                         : 0

  Prefix-SID type                  : Index

  Value                            : 10

  Prefix-SID validity              : Valid

# Display SRGB information on Router A.

[RouterA] display isis segment-routing global-block

 

             Segment routing global block information for IS-IS(1)

             -----------------------------------------------------

 

                                  Level-1 SRGB

                                  ------------

 

System ID                          Base                Range

-------------------------------------------------------------------------------

0000.0000.0001                     16000               1000

0000.0000.0002                     17000               1000

0000.0000.0003                     18000               1000

0000.0000.0004                     19000               1000

# Display detailed IS-IS routing information on Router A to view information about routes bound with labels.

[RouterA] display isis route verbose

 

                         Route information for IS-IS(1)

                         ------------------------------

 

                         Level-1 IPv4 Forwarding Table

                         -----------------------------

 

 IPv4 Dest : 10.0.0.0/24         Int. Cost  : 10               Ext. Cost  : NULL

 Admin Tag : -                   Src Count  : 2                Flag       : D/L/-

 InLabel   : 4294967295          InLabel Flag: -/-/-/-/-/-

 NextHop   :                     Interface  :                  ExitIndex  :

    Direct                             HGE1/0/1                    0x00000102

 Nib ID    : 0x0                 OutLabel   : 4294967295       OutLabelFlag: -

 

 IPv4 Dest : 11.0.0.0/24         Int. Cost  : 20               Ext. Cost  : NULL

 Admin Tag : -                   Src Count  : 2                Flag       : R/-/-

 InLabel   : 4294967295          InLabel Flag: -/-/-/-/-/-

 NextHop   :                     Interface  :                  ExitIndex  :

    10.0.0.2                           HGE1/0/1                    0x00000102

 Nib ID    : 0x14000004          OutLabel   : 4294967295       OutLabelFlag: -

 

 IPv4 Dest : 12.0.0.0/24         Int. Cost  : 30               Ext. Cost  : NULL

 Admin Tag : -                   Src Count  : 2                Flag       : R/-/-

 InLabel   : 4294967295          InLabel Flag: -/-/-/-/-/-

 NextHop   :                     Interface  :                  ExitIndex  :

    10.0.0.2                           HGE1/0/1                    0x00000102

 Nib ID    : 0x14000004          OutLabel   : 4294967295       OutLabelFlag: -

 

 IPv4 Dest : 1.1.1.1/32          Int. Cost  : 0                Ext. Cost  : NULL

 Admin Tag : -                   Src Count  : 1                Flag       : D/L/-

 InLabel   : 16010               InLabel Flag: -/N/-/-/-/-

 NextHop   :                     Interface  :                  ExitIndex  :

    Direct                             Loop1                      0x00000584

 Nib ID    : 0x0                 OutLabel   : 4294967295       OutLabelFlag: -

 

 IPv4 Dest : 2.2.2.2/32          Int. Cost  : 10               Ext. Cost  : NULL

 Admin Tag : -                   Src Count  : 1                Flag       : R/-/-

 InLabel   : 16020               InLabel Flag: -/N/-/-/-/-

 NextHop   :                     Interface  :                  ExitIndex  :

    10.0.0.2                           HGE1/0/1                    0x00000102

 Nib ID    : 0x14000003          OutLabel   : 17020            OutLabelFlag: I

 

 IPv4 Dest : 3.3.3.3/32          Int. Cost  : 20               Ext. Cost  : NULL

 Admin Tag : -                   Src Count  : 1                Flag       : R/-/-

 InLabel   : 16030               InLabel Flag: -/N/-/-/-/-

 NextHop   :                     Interface  :                  ExitIndex  :

    10.0.0.2                           HGE1/0/1                    0x00000102

 Nib ID    : 0x14000002          OutLabel   : 17030            OutLabelFlag: -

 

 IPv4 Dest : 4.4.4.4/32          Int. Cost  : 20               Ext. Cost  : NULL

 Admin Tag : -                   Src Count  : 1                Flag       : R/-/-

 InLabel   : 16040               InLabel Flag: -/N/-/-/-/-

 NextHop   :                     Interface  :                  ExitIndex  :

    10.0.0.2                           HGE1/0/1                    0x00000102

 Nib ID    : 0x14000002          OutLabel   : 17040            OutLabelFlag: -

 

      Flags: D-Direct, R-Added to Rib, L-Advertised in LSPs, U-Up/Down Bit Set

 

      InLabel flags: R-Readvertisement, N-Node SID, P-no PHP

                     E-Explicit null, V-Value, L-Local

 

      OutLabelFlags: E-Explicit null, I-Implicit null, N-Normal

# Display MPLS LSP information on Router A.

[RouterA] display mpls lsp

FEC                         Proto     In/Out Label    Out Inter/NHLFE/LSINDEX

10.0.0.2                    Local     -/-             HGE1/0/1

1.1.1.1/32                  ISIS      16010/-         -

2.2.2.2/32                  ISIS      16020/3         HGE1/0/1

2.2.2.2/32                  ISIS      -/3             HGE1/0/1

3.3.3.3/32                  ISIS      16030/17030     HGE1/0/1

3.3.3.3/32                  ISIS      -/17030         HGE1/0/1

4.4.4.4/32                  ISIS      16040/17040     HGE1/0/1

4.4.4.4/32                  ISIS      -/17040         HGE1/0/1

Example: Configuring an SR-based MPLS TE tunnel over an explicit path

Network configuration

As shown in Figure 19, Router A, Router B, Router C, and Router D are running IS-IS.

Configure dynamic SID allocation on loopback interfaces of the routers. Then, create an explicit path from Router A to Router D and configure the MPLS TE tunnel interface to use SR to establish an MPLS TE tunnel over the explicit path.

Figure 19 Network diagram

Table 3 Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

Router A

Loop1

1.1.1.1/32

Router B

Loop1

2.2.2.2/32

 

HGE1/0/1

10.0.0.1/24

 

HGE1/0/1

10.0.0.2/24

 

 

 

 

HGE1/0/2

11.0.0.1/24

Router C

Loop1

3.3.3.3/32

Router D

Loop1

4.4.4.4/32

 

HGE1/0/1

11.0.0.2/24

 

HGE1/0/1

12.0.0.2/24

 

HGE1/0/2

12.0.0.1/24

 

HGE1/0/2

100.1.2.1/24

 

Prerequisites

Configure IP addresses and masks for interfaces.

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

Procedure

1.     Configure IS-IS on the routers to achieve network level connectivity and set the IS-IS cost style to wide:

# Configure Router A.

<RouterA> system-view

[RouterA] isis 1

[RouterA-isis-1] network-entity 00.0000.0000.0001.00

[RouterA-isis-1] cost-style wide

[RouterA-isis-1] is-level level-1

[RouterA-isis-1] mpls te enable

[RouterA-isis-1] quit

[RouterA] interface hundredgige 1/0/1

[RouterA-HundredGigE1/0/1] isis enable 1

[RouterA-HundredGigE1/0/1] quit

[RouterA] interface loopback 1

[RouterA-LoopBack1] isis enable 1

[RouterA-LoopBack1] quit

# Configure Router B.

<RouterB> system-view

[RouterB] isis 1

[RouterB-isis-1] network-entity 00.0000.0000.0002.00

[RouterB-isis-1] cost-style wide

[RouterB-isis-1] is-level level-1

[RouterB-isis-1] mpls te enable

[RouterB-isis-1] quit

[RouterB] interface hundredgige 1/0/1

[RouterB-HundredGigE1/0/1] isis enable 1

[RouterB-HundredGigE1/0/1] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] isis enable 1

[RouterB-HundredGigE1/0/2] quit

[RouterB] interface loopback 1

[RouterB-LoopBack1] isis enable 1

[RouterB-LoopBack1] quit

# Configure Router C.

<RouterC> system-view

[RouterC] isis 1

[RouterC-isis-1] network-entity 00.0000.0000.0003.00

[RouterC-isis-1] cost-style wide

[RouterC-isis-1] is-level level-1

[RouterC-isis-1] mpls te enable

[RouterC-isis-1] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] isis enable 1

[RouterC-HundredGigE1/0/1] quit

[RouterC] interface hundredgige 1/0/2

[RouterC-HundredGigE1/0/2] isis enable 1

[RouterC-HundredGigE1/0/2] quit

[RouterC] interface loopback 1

[RouterC-LoopBack1] isis enable 1

[RouterC-LoopBack1] quit

# Configure Router D.

<RouterD> system-view

[RouterD] isis 1

[RouterD-isis-1] network-entity 00.0000.0000.0004.00

[RouterD-isis-1] cost-style wide

[RouterD-isis-1] is-level level-1

[RouterD-isis-1] mpls te enable

[RouterD-isis-1] quit

[RouterD] interface hundredgige 1/0/1

[RouterD-HundredGigE1/0/1] isis enable 1

[RouterD-HundredGigE1/0/1] quit

[RouterD] interface hundredgige 1/0/2

[RouterD-HundredGigE1/0/2] isis enable 1

[RouterD-HundredGigE1/0/2] quit

[RouterD] interface loopback 1

[RouterD-LoopBack1] isis enable 1

[RouterD-LoopBack1] quit

2.     Configure LSR IDs, and enable MPLS and MPLS TE:

# Configure Router A.

[RouterA] mpls lsr-id 1.1.1.1

[RouterA] mpls te

[RouterA-te] quit

[RouterA] interface hundredgige 1/0/1

[RouterA-HundredGigE1/0/1] mpls enable

[RouterA-HundredGigE1/0/1] quit

# Configure Router B.

[RouterB] mpls lsr-id 2.2.2.2

[RouterB] mpls te

[RouterB-te] quit

[RouterB] interface hundredgige 1/0/1

[RouterB-HundredGigE1/0/1] mpls enable

[RouterB-HundredGigE1/0/1] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] mpls enable

[RouterB-HundredGigE1/0/2] quit

# Configure Router C.

[RouterC] mpls lsr-id 3.3.3.3

[RouterC] mpls te

[RouterC-te] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] mpls enable

[RouterC-HundredGigE1/0/1] quit

[RouterC] interface hundredgige 1/0/2

[RouterC-HundredGigE1/0/2] mpls enable

[RouterC-HundredGigE1/0/2] quit

# Configure Router D.

[RouterD] mpls lsr-id 4.4.4.4

[RouterD] mpls te

[RouterD-te] quit

[RouterD] interface hundredgige 1/0/1

[RouterD-HundredGigE1/0/1] mpls enable

[RouterD-HundredGigE1/0/1] quit

3.     Configure SRGBs and enable SR-MPLS on the routers:

# Configure Router A.

[RouterA] isis 1

[RouterA-isis-1] segment-routing global-block 16000 16999

[RouterA-isis-1] address-family ipv4

[RouterA-isis-1-ipv4] segment-routing mpls

[RouterA-isis-1-ipv4] quit

[RouterA-isis-1] quit

# Configure Router B.

[RouterB] isis 1

[RouterB-isis-1] segment-routing global-block 17000 17999

[RouterB-isis-1] address-family ipv4

[RouterB-isis-1-ipv4] segment-routing mpls

[RouterB-isis-1-ipv4] quit

[RouterB-isis-1] quit

# Configure Router C.

[RouterC] isis 1

[RouterC-isis-1] segment-routing global-block 18000 18999

[RouterC-isis-1] address-family ipv4

[RouterC-isis-1-ipv4] segment-routing mpls

[RouterC-isis-1-ipv4] quit

[RouterC-isis-1] quit

# Configure Router D.

[RouterD] isis 1

[RouterD-isis-1] segment-routing global-block 19000 19999

[RouterD-isis-1] address-family ipv4

[RouterD-isis-1-ipv4] segment-routing mpls

[RouterD-isis-1-ipv4] quit

[RouterD-isis-1] quit

4.     Configure IS-IS prefix SIDs for the routers:

# Configure Router A.

[RouterA] interface loopback 1

[RouterA-LoopBack1] isis prefix-sid index 10

[RouterA-LoopBack1] quit

# Configure Router B.

[RouterB] interface loopback 1

[RouterB-LoopBack1] isis prefix-sid index 20

[RouterB-LoopBack1] quit

# Configure Router C.

[RouterC] interface loopback 1

[RouterC-LoopBack1] isis prefix-sid index 30

[RouterC-LoopBack1] quit

# Configure Router D.

[RouterD] interface loopback 1

[RouterD-LoopBack1] isis prefix-sid index 40

[RouterD-LoopBack1] quit

5.     Configure an explicit path on Router A.

# Create an explicit path to Router D and specify the nodes by their prefix labels.

[RouterA] explicit-path 1

[RouterA-explicit-path-1] nextsid label 16020 type prefix

[RouterA-explicit-path-1] nextsid label 17030 type prefix

[RouterA-explicit-path-1] nextsid label 18040 type prefix

[RouterA-explicit-path-1] quit

6.     Configure an MPLS TE tunnel on Router A:

# Configure MPLS TE tunnel interface Tunnel 1.

[RouterA] interface tunnel 1 mode mpls-te

[RouterA-Tunnel1] ip address unnumbered interface LoopBack 1

# Set the tunnel destination address to the IP address of the loopback interface on Router D.

[RouterA-Tunnel1] destination 4.4.4.4

# Configure the MPLS TE tunnel interface to use SR to establish a tunnel over the explicit path.

[RouterA-Tunnel1] mpls te signaling segment-routing

[RouterA-Tunnel1] mpls te path preference 1 explicit-path 1

[RouterA-Tunnel1] quit

Verifying the configuration

# Display MPLS LSP information on Router A.

[RouterA] display mpls lsp

FEC                         Proto       In/Out Label    Out Inter/NHLFE/LSINDEX

10.0.0.2                    Local       -/-             HGE1/0/1

Tunnel1                     Local       -/-             NHLFE6

1.1.1.1/32                  ISIS        16010/-         -

2.2.2.2/32                  ISIS        16020/3         HGE1/0/1

2.2.2.2/32                  ISIS        -/3             HGE1/0/1

3.3.3.3/32                  ISIS        16030/17030     HGE1/0/1

3.3.3.3/32                  ISIS        -/17030         HGE1/0/1

4.4.4.4/32                  ISIS        16040/17040     HGE1/0/1

4.4.4.4/32                  ISIS        -/17040         HGE1/0/1

1.1.1.1/1/17700             SR-TE       -/17030         HGE1/0/1

                                          18040

# Display information about MPLS TE tunnel interface Tunnel 1 on Router A.

[RouterA] display mpls te tunnel-interface tunnel 1

Tunnel Name            : Tunnel 1

Tunnel State           : Up (Main CRLSP up.

                             Main Shared-resource CRLSP down.

                             Backup CRLSP down.)

Tunnel Attributes      :

  LSP ID               : 17700           Tunnel ID            : 1

  Admin State          : Normal

  Ingress LSR ID       : 1.1.1.1         Egress LSR ID        : 4.4.4.4

  Signaling            : Segment-Routing Static CRLSP Name    : -

  Resv Style           : SE

  Tunnel mode          : -

  Reverse-LSP name     : -

  Reverse-LSP LSR ID   : -               Reverse-LSP Tunnel ID: -

  Class Type           : CT0             Tunnel Bandwidth     : 0 kbps

  Reserved Bandwidth   : 0 kbps

  Setup Priority       : -               Holding Priority     : -

  Affinity Attr/Mask   : 0/0

  Explicit Path        : 1

  Backup Explicit Path : -

  Metric Type          : TE

  Record Route         : Disabled        Record Label         : Disabled

  FRR Flag             : Disabled        Bandwidth Protection : Disabled

  Backup Bandwidth Flag: Disabled        Backup Bandwidth Type: -

  Backup Bandwidth     : -

  Bypass Tunnel        : No              Auto Created         : No

  Route Pinning        : Disabled

  Retry Limit          : 3               Retry Interval       : 2 sec

  Reoptimization       : Disabled        Reoptimization Freq  : -

  Backup Type          : None            Backup LSP ID        : -

  Backup Restore Time  : -

  Auto Bandwidth       : Disabled        Auto Bandwidth Freq  : -

  Min Bandwidth        : -               Max Bandwidth        : -

  Collected Bandwidth  : -               Service-Class        : -

  Traffic Policy       : Disable

  Path Setup Type      : EXPLICIT/-

  Last Down Reason     : Signal Error

  Down Time            : 18-11-13 14:34:06:232

# Display the NHLFE entry information.

[RouterA] display mpls forwarding nhlfe

Total NHLFE entries: 3

 

Flags: T - Forwarded through a tunnel

       N - Forwarded through the outgoing interface to the nexthop IP address

       B - Backup forwarding information

       A - Active forwarding information

       M - P2MP forwarding information

 

NID        Tnl-Type   Flag OutLabel Forwarding Info

--------------------------------------------------------------------------------

5          LOCAL      NA   -        HGE1/0/1                  10.0.0.2

6          SRLSP      NA   17030    HGE1/0/1                  10.0.0.2

                           18040

268435457  TE         TA   -        6

The output shows that there are two tiers of outgoing labels to the destination. The traffic is forwarded through the explicit path.

Example: Configuring SR-MPLS inter-AS option B

Network configuration

As shown in Figure 20, complete the following tasks:

·     Start OSPF and enable OSPF-based SR-MPLS on the PEs in the same AS.

·     Establish an MPLS TE tunnel between ASBR-PEs in different ASs and enable BGP EPE.

·     Configure PE 1 and ASBR-PE 1 to exchange VPNv4 routes through MP IBGP.

·     Configure PE 2 and ASBR-PE 2 to exchange VPNv4 routes through MP IBGP.

·     Establish an MP-EBGP peer relationship between ASBR-PE 1 and ASBR-PE 2 to exchange VPNv4 routes.

·     Disable route target-based filtering of received VPNv4 routes on ASBR-PE 1 and ASBR-PE 2.

·     Configure dynamic SID allocation on loopback interfaces of the devices. Then, establish an SRLSP based on the allocated SIDs and configure an MPLS TE tunnel over the SRLSP to transmit data.

Figure 20 Network diagram

Table 4 Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

PE 1

Loop1

2.2.2.9/32

PE 2

Loop1

5.5.5.9/32

 

HGE1/0/1

30.0.0.1/24

 

HGE1/0/1

20.0.0.1/24

 

HGE1/0/5

1.1.1.2/8

 

HGE1/0/5

9.1.1.2/8

ASBR-PE 1

Loop1

3.3.3.9/32

ASBR-PE 2

Loop1

4.4.4.9/32

 

HGE1/0/5

1.1.1.1/8

 

HGE1/0/5

9.1.1.1/8

 

HGE1/0/4

11.0.0.2/8

 

HGE1/0/4

11.0.0.1/8

 

Prerequisites

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

Procedure

1.     Configure IP addresses and masks for interfaces. (Details not shown.)

2.     Configure PE 1:

# Start OSPF on PE 1, set the LSR ID, and enable MPLS and MPLS TE.

<PE1> system-view

[PE1] ospf 1 router-id 2.2.2.9

[PE1-ospf-1] quit

[PE1] interface hundredgige 1/0/5

[PE1-HundredGigE1/0/5] ip address 1.1.1.2 255.0.0.0

[PE1-HundredGigE1/0/5] ospf 1 area 0

[PE1-HundredGigE1/0/5] mpls enable

[PE1-HundredGigE1/0/5] quit

[PE1] interface loopback 1

[PE1-LoopBack1] ip address 2.2.2.9 32

[PE1-LoopBack1] ospf 1 area 0

[PE1-LoopBack1] quit

[PE1] mpls lsr-id 2.2.2.9

[PE1] mpls te

[PE1-te] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[PE1] ospf 1

[PE1-ospf-1] segment-routing mpls

[PE1-ospf-1] quit

[PE1] interface loopback 1

[PE1-LoopBack1] ospf 1 prefix-sid index 20

[PE1-LoopBack1] quit

# Create VPN instance vpn1, and configure the RD and route target attributes.

[PE1] ip vpn-instance vpn1

[PE1-vpn-instance-vpn1] route-distinguisher 11:11

[PE1-vpn-instance-vpn1] vpn-target 1:1 2:2 3:3 import-extcommunity

[PE1-vpn-instance-vpn1] vpn-target 3:3 export-extcommunity

[PE1-vpn-instance-vpn1] quit

# Associate HundredGigE 1/0/1 with VPN instance vpn1, and assign an IP address to the interface.

[PE1] interface hundredgige 1/0/1

[PE1-HundredGigE1/0/1] ip binding vpn-instance vpn1

[PE1-HundredGigE1/0/1] ip address 30.0.0.1 24

[PE1-HundredGigE1/0/1] quit

# Start BGP on PE 1.

[PE1] bgp 100

# Configure peer 3.3.3.9 as a VPNv4 peer.

[PE1-bgp-default] peer 3.3.3.9 as-number 100

[PE1-bgp-default] peer 3.3.3.9 connect-interface loopback 1

[PE1-bgp-default] address-family vpnv4

[PE1-bgp-default-vpnv4] peer 3.3.3.9 enable

[PE1-bgp-default-vpnv4] quit

# Redistribute direct routes to the VPN routing table of vpn1.

[PE1-bgp-default] ip vpn-instance vpn1

[PE1-bgp-default-vpn1] address-family ipv4 unicast

[PE1-bgp-default-ipv4-vpn1] import-route direct

3.     Configure ASBR-PE 1:

# Start OSPF on ASBR-PE 1, set the LSR ID, and enable MPLS and MPLS TE.

<ASBR-PE1> system-view

[ASBR-PE1] ospf 1 router-id 3.3.3.9

[ASBR-PE1-ospf-1] quit

[ASBR-PE1] interface hundredgige 1/0/4

[ASBR-PE1-HundredGigE1/0/4] mpls enable

[ASBR-PE1-HundredGigE1/0/4] quit

[ASBR-PE1] interface hundredgige 1/0/5

[ASBR-PE1-HundredGigE1/0/5] ospf 1 area 0

[ASBR-PE1-HundredGigE1/0/5] mpls enable

[ASBR-PE1-HundredGigE1/0/5] quit

[ASBR-PE1] interface loopback 1

[ASBR-PE1-LoopBack1] ip address 3.3.3.9 32

[ASBR-PE1-LoopBack1] ospf 1 area 0

[ASBR-PE1-LoopBack1] quit

[ASBR-PE1] mpls lsr-id 3.3.3.9

[ASBR-PE1] mpls te

[ASBR-PE1-te] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[ASBR-PE1] ospf 1

[ASBR-PE1-ospf-1] segment-routing mpls

[ASBR-PE1-ospf-1] quit

[ASBR-PE1] interface loopback 1

[ASBR-PE1-LoopBack1] ospf 1 prefix-sid index 30

[ASBR-PE1-LoopBack1] quit

# Create a routing policy to assign a label.

[ASBR-PE1] route-policy epe permit node 1

[ASBR-PE1-route-policy-epe-1] apply label-value 5555

[ASBR-PE1-route-policy-epe-1] quit

# Start BGP on ASBR-PE 1.

[ASBR-PE1] bgp 100

[ASBR-PE1-bgp-default] peer 2.2.2.9 as-number 100

[ASBR-PE1-bgp-default] peer 2.2.2.9 connect-interface loopback 1

[ASBR-PE1-bgp-default] peer 11.0.0.1 as-number 600

[ASBR-PE1-bgp-default] peer 11.0.0.1 connect-interface hundredgige 1/0/4

# Disable route target-based filtering of received VPNv4 routes.

[ASBR-PE1-bgp-default] address-family vpnv4

[ASBR-PE1-bgp-default-vpnv4] undo policy vpn-target

# Configure IBGP peer 2.2.2.9 and EBGP peer 11.0.0.1 as a VPNv4 peer.

[ASBR-PE1-bgp-default-vpnv4] peer 11.0.0.1 enable

[ASBR-PE1-bgp-default-vpnv4] peer 2.2.2.9 enable

[ASBR-PE1-bgp-default-vpnv4] quit

# Enable BGP EPE for EBGP neighbor 11.0.0.1 and specify a routing policy to assign a label to the neighbor.

[ASBR-PE1-bgp-default] peer 11.0.0.1 egress-engineering route-policy epe

[ASBR-PE1-bgp-default] quit

[ASBR-PE1-bgp] quit

4.     Configure ASBR-PE 2:

# Start OSPF on ASBR-PE 2, set the LSR ID, and enable MPLS and MPLS TE.

<ASBR-PE2> system-view

[ASBR-PE2] ospf 1 router-id 4.4.4.9

[ASBR-PE2-ospf-1] quit

[ASBR-PE2] interface hundredgige 1/0/4

[ASBR-PE2-HundredGigE1/0/4] mpls enable

[ASBR-PE2-HundredGigE1/0/4] quit

[ASBR-PE2] interface hundredgige 1/0/5

[ASBR-PE2-HundredGigE1/0/5] ospf 1 area 0

[ASBR-PE2-HundredGigE1/0/5] mpls enable

[ASBR-PE2-HundredGigE1/0/5] quit

[ASBR-PE2] interface loopback 1

[ASBR-PE2-LoopBack1] ip address 4.4.4.9 32

[ASBR-PE2-LoopBack1] ospf 1 area 0

[ASBR-PE2-LoopBack1] quit

[ASBR-PE2] mpls lsr-id 4.4.4.9

[ASBR-PE2] mpls te

[ASBR-PE2-te] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[ASBR-PE1] ospf 1

[ASBR-PE1-ospf-1] segment-routing mpls

[ASBR-PE1-ospf-1] quit

[ASBR-PE1] interface loopback 1

[ASBR-PE1-LoopBack1] ospf 1 prefix-sid index 40

[ASBR-PE1-LoopBack1] quit

# Create a routing policy to assign a label.

[ASBR-PE2] route-policy epe permit node 1

[ASBR-PE2-route-policy-epe-1] apply label-value 6666

[ASBR-PE2-route-policy-epe-1] quit

# Start BGP on ASBR-PE 2.

[ASBR-PE2] bgp 600

[ASBR-PE2-bgp-default] peer 5.5.5.9 as-number 600

[ASBR-PE2-bgp-default] peer 5.5.5.9 connect-interface loopback 1

[ASBR-PE2-bgp-default] peer 11.0.0.2 as-number 100

[ASBR-PE2-bgp-default] peer 11.0.0.2 connect-interface hundredgige 1/0/4

# Disable route target-based filtering of received VPNv4 routes.

[ASBR-PE2-bgp-default] address-family vpnv4

[ASBR-PE2-bgp-default-vpnv4] undo policy vpn-target

# Configure IBGP peer 5.5.5.9 and EBGP peer 11.0.0.2 as a VPNv4 peer.

[ASBR-PE2-bgp-default-vpnv4] peer 11.0.0.2 enable

[ASBR-PE2-bgp-default-vpnv4] peer 5.5.5.9 enable

[ASBR-PE2-bgp-default-vpnv4] quit

# Enable BGP EPE for EBGP neighbor 11.0.0.2 and specify a routing policy to assign a label to the neighbor.

[ASBR-PE2-bgp-default] peer 11.0.0.2 egress-engineering route-policy epe

5.     Configure PE 2:

# Start OSPF on PE 2, set the LSR ID, and enable MPLS and MPLS TE.

<PE2> system-view

[PE2] ospf 1 router-id 5.5.5.9

[PE2-ospf-1] quit

[PE2] interface hundredgige 1/0/1

[PE2-HundredGigE1/0/1] ospf 1 area 0

[PE2-HundredGigE1/0/1] mpls enable

[PE2-HundredGigE1/0/1] quit

[PE2] interface hundredgige 1/0/5

[PE2-HundredGigE1/0/5] ospf 1 area 0

[PE2-HundredGigE1/0/5] mpls enable

[PE2-HundredGigE1/0/5] quit

[PE2] interface loopback 1

[PE2-LoopBack1] ip address 5.5.5.9 32

[PE2-LoopBack1] ospf 1 area 0

[PE2-LoopBack1] quit

[PE2] mpls lsr-id 5.5.5.9

[PE2] mpls te

[PE2-te] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[PE2] ospf 1

[PE2-ospf-1] segment-routing mpls

[PE2] interface loopback 1

[PE2-LoopBack1] ospf 1 prefix-sid index 50

[PE2-LoopBack1] quit

# Create VPN instance vpn1, and configure the RD and route target attributes.

[PE2] ip vpn-instance vpn1

[PE2-vpn-instance-vpn1] route-distinguisher 11:11

[PE2-vpn-instance-vpn1] vpn-target 1:1 2:2 3:3 import-extcommunity

[PE2-vpn-instance-vpn1] vpn-target 3:3 export-extcommunity

[PE2-vpn-instance-vpn1] quit

# Associate HundredGigE 1/0/1 with VPN instance vpn1, and assign an IP address to the interface.

[PE2] interface hundredgige 1/0/1

[PE2-HundredGigE1/0/1] ip binding vpn-instance vpn1

[PE2-HundredGigE1/0/1] ip address 20.0.0.1 24

[PE2-HundredGigE1/0/1] quit

# Start BGP on PE 2.

[PE2] bgp 600

# Configure IBGP peer 4.4.4.9 as a VPNv4 peer.

[PE2-bgp-default] peer 4.4.4.9 as-number 600

[PE2-bgp-default] peer 4.4.4.9 connect-interface loopback 1

[PE2-bgp-default] address-family vpnv4

[PE2-bgp-default-vpnv4] peer 4.4.4.9 enable

[PE2-bgp-default-vpnv4] quit

# Redistribute direct routes to the VPN routing table of vpn1.

[PE2-bgp-default] ip vpn-instance vpn1

[PE2-bgp-default-vpn1] address-family ipv4 unicast

[PE2-bgp-default-ipv4-vpn1] import-route direct

6.     Configuring an MPLS TE tunnel:

# Configure ASBR-PE 1 as the ingress node of static SRLSP static-sr-lsp-1 and specify the label that ASBR-PE 1 allocated to ASBR-PE 2 (5555) as the outgoing label.

<ASBR-PE1> system-view

[ASBR-PE1] static-sr-mpls lsp static-sr-lsp-1 out-label 5555

# On ASBR-PE 1, establish static MPLS TE tunnel 1 to ASBR-PE 2. Specify the IP address (11.0.0.1) of the directly connected interface on ASBR-PE 2 as the tunnel destination address. Bind static SRLSP static-sr-lsp-1 to MPLS TE tunnel interface 1.

[ASBR-PE1] interface tunnel 1 mode mpls-te

[ASBR-PE1-Tunnel1] ip address 6.1.1.1 255.255.255.0

[ASBR-PE1-Tunnel1] destination 11.0.0.1

[ASBR-PE1-Tunnel1] mpls te signaling static

[ASBR-PE1-Tunnel1] mpls te static-sr-mpls static-sr-lsp-1

[ASBR-PE1-Tunnel1] quit

# Configure ASBR-PE 2 as the ingress node of static SRLSP static-sr-lsp-2 and specify the label that ASBR-PE 2 allocated to ASBR-PE 1 (6666) as the outgoing label.

<ASBR-PE2> system-view

[ASBR-PE2] static-sr-mpls lsp static-sr-lsp-2 out-label 6666

# On ASBR-PE 2, establish static MPLS TE tunnel 1 to ASBR-PE 1. Specify the IP address (11.0.0.2) of the directly connected interface on ASBR-PE 1 as the tunnel destination address. Bind static SRLSP static-sr-lsp-2 to MPLS TE tunnel interface 1.

[ASBR-PE2] interface tunnel 1 mode mpls-te

[ASBR-PE2-Tunnel1] ip address 7.1.1.1 255.255.255.0

[ASBR-PE2-Tunnel1] destination 11.0.0.2

[ASBR-PE2-Tunnel1] mpls te signaling static

[ASBR-PE2-Tunnel1] mpls te static-sr-mpls static-sr-lsp-2

[ASBR-PE2-Tunnel1] quit

Verifying the configuration

# Execute the display ip routing-table command on CE 1 and CE 2 to verify that they have a route to each other. (Details not shown.)

# Verify that CE 1 and CE 2 can ping each other. (Details not shown.)

# Display MPLS LSP information on ASBR-PE1.

[ASBR-PE1] display mpls lsp

FEC                         Proto       In/Out Label    Out Inter/NHLFE/LSINDEX

3.3.3.9/1/53168             StaticCR    -/-             NHLFE1

11.0.0.1                    BGP         -/-             HGE1/0/4

2.2.2.9/1151                BGP         1151/1151       -

11.0.0.1/1149               BGP         1150/1149       -

11.0.0.1                    BGP         5555/-          NHLFE1

1.1.1.2                     Local       -/-             HGE1/0/5

11.0.0.1                    Local       -/-             HGE1/0/4

Tunnel1                     Local       -/-             NHLFE4

2.2.2.9/32                  OSPF        16020/3         HGE1/0/5

2.2.2.9/32                  OSPF        -/3             HGE1/0/5

3.3.3.9/32                  OSPF        16030/-         -

Example: Configuring SR-MPLS inter-AS option C (I)

Network configuration

As shown in Figure 21, complete the following tasks:

·     Start OSPF and enable OSPF-based SR-MPLS on the PEs in the same AS.

·     Configure PE 1 and ASBR-PE 1 to exchange labeled IPv4 routes through IBGP.

·     Configure PE 2 and ASBR-PE 2 to exchange labeled IPv4 routes through IBGP.

·     Establish an MP-EBGP peer relationship between PE 1 and PE 2 to exchange VPNv4 routes.

·     Configure ASBR-PE 1 and ASBR-PE 2 to exchange labeled IPv4 routes through EBGP. Enable BGP-based SR-MPLS.

·     Configure dynamic SID allocation on loopback interfaces of the devices. Then, establish an SRLSP based on the allocated SIDs and configure an MPLS TE tunnel over the SRLSP to transmit data.

Figure 21 Network diagram

Table 5 Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

PE 1

Loop1

2.2.2.9/32

PE 2

Loop1

5.5.5.9/32

 

HGE1/0/1

30.0.0.1/24

 

HGE1/0/1

20.0.0.1/24

 

HGE1/0/5

1.1.1.2/8

 

HGE1/0/5

9.1.1.2/8

ASBR-PE 1

Loop1

3.3.3.9/32

ASBR-PE 2

Loop1

4.4.4.9/32

 

HGE1/0/5

1.1.1.1/8

 

HGE1/0/5

9.1.1.1/8

 

HGE1/0/4

11.0.0.2/8

 

HGE1/0/4

11.0.0.1/8

CE 1

HGE1/0/1

30.0.0.2/24

CE 2

HGE1/0/1

20.0.0.2/24

 

Prerequisites

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

Procedure

1.     Configure IP addresses and masks for interfaces. (Details not shown.)

2.     Configure CE 1:

# Assign an IP address to interface HundredGigE 1/0/1.

<CE1> system-view

[CE1] interface hundredgige 1/0/1

[CE1-HundredGigE1/0/1] ip address 30.0.0.2 24

[CE1-HundredGigE1/0/1] quit

# Configure PE 1 as an EBGP peer and redistribute the VPN route.

[CE1] bgp 65001

[CE1-bgp-default] peer 30.0.0.1 as-number 100

[CE1-bgp-default] address-family ipv4 unicast

[CE1-bgp-default-ipv4] peer 30.0.0.1 enable

[CE1-bgp-default-ipv4] import-route direct

[CE1-bgp-default-ipv4] quit

[CE1-bgp-default] quit

3.     Configure PE 1:

# Start OSPF on PE 1, set the LSR ID, and enable MPLS and MPLS TE.

<PE1> system-view

[PE1] ospf 1 router-id 2.2.2.9

[PE1-ospf-1] quit

[PE1] interface hundredgige 1/0/1

[PE1-HundredGigE1/0/1] mpls enable

[PE1-HundredGigE1/0/1] quit

[PE1] interface hundredgige 1/0/5

[PE1-HundredGigE1/0/5] ospf 1 area 0

[PE1-HundredGigE1/0/5] mpls enable

[PE1-HundredGigE1/0/5] quit

[PE1] interface loopback 1

[PE1-LoopBack1] ip address 2.2.2.9 32

[PE1-LoopBack1] ospf 1 area 0

[PE1-LoopBack1] quit

[PE1] mpls lsr-id 2.2.2.9

[PE1] mpls te

[PE1-te] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[PE1] ospf 1

[PE1-ospf-1] segment-routing mpls

[PE1-ospf-1] quit

[PE1] interface loopback 1

[PE1-LoopBack1] ospf 1 prefix-sid index 20

[PE1-LoopBack1] quit

# Create VPN instance vpn1. Configure an RD and both import and export route targets for the VPN instance.

[PE1] ip vpn-instance vpn1

[PE1-vpn-instance-vpn1] route-distinguisher 11:11

[PE1-vpn-instance-vpn1] vpn-target 1:1 2:2 3:3 import-extcommunity

[PE1-vpn-instance-vpn1] vpn-target 3:3 export-extcommunity

[PE1-vpn-instance-vpn1] quit

# Bind VPN instance vpn1 to interface HundredGigE 1/0/1 and assign an IP address to the interface.

[PE1] interface hundredgige 1/0/1

[PE1-HundredGigE1/0/1] ip binding vpn-instance vpn1

[PE1-HundredGigE1/0/1] ip address 30.0.0.1 24

[PE1-HundredGigE1/0/1] quit

# Start BGP on PE 1.

[PE1] bgp 100

# Enable the capability to exchange labeled routes with IBGP peer 3.3.3.9.

[PE1-bgp-default] peer 3.3.3.9 as-number 100

[PE1-bgp-default] peer 3.3.3.9 connect-interface loopback 1

[PE1-bgp-default] address-family ipv4 unicast

[PE1-bgp-default-ipv4] peer 3.3.3.9 enable

[PE1-bgp-default-ipv4] peer 3.3.3.9 label-route-capability

# Enable SR-MPLS.

[PE1-bgp-default-ipv4] segment-routing mpls

[PE1-bgp-default-ipv4] quit

# Configure the maximum number of hops from PE 1 to EBGP peer 5.5.5.9 as 10.

[PE1-bgp-default] peer 5.5.5.9 as-number 600

[PE1-bgp-default] peer 5.5.5.9 connect-interface loopback 1

[PE1-bgp-default] peer 5.5.5.9 ebgp-max-hop 10

# Configure peer 5.5.5.9 as a VPNv4 peer.

[PE1-bgp-default] address-family vpnv4

[PE1-bgp-default-vpnv4] peer 5.5.5.9 enable

[PE1-bgp-default-vpnv4] quit

# Configure CE 1 as an EBGP peer of PE 1 and install the learned BGP routes in the routing table of the VPN instance.

[PE1-bgp-default] address-family vpnv4

4.     Configure ASBR-PE 1:

# Start OSPF on ASBR-PE 1, set the LSR ID, and enable MPLS and MPLS TE.

<ASBR-PE1> system-view

[ASBR-PE1] ospf 1 router-id 3.3.3.9

[ASBR-PE1-ospf-1] quit

[ASBR-PE1] interface hundredgige 1/0/4

[ASBR-PE1-HundredGigE1/0/4] mpls enable

[ASBR-PE1-HundredGigE1/0/4] quit

[ASBR-PE1] interface hundredgige 1/0/5

[ASBR-PE1-HundredGigE1/0/5] ospf 1 area 0

[ASBR-PE1-HundredGigE1/0/5] mpls enable

[ASBR-PE1-HundredGigE1/0/5] quit

[ASBR-PE1] interface loopback 1

[ASBR-PE1-LoopBack1] ip address 3.3.3.9 32

[ASBR-PE1-LoopBack1] ospf 1 area 0

[ASBR-PE1-LoopBack1] quit

[ASBR-PE1] mpls lsr-id 3.3.3.9

[ASBR-PE1] mpls te

[ASBR-PE1-te] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[ASBR-PE1] ospf 1

[ASBR-PE1-ospf-1] segment-routing mpls

[ASBR-PE1-ospf-1] quit

[ASBR-PE1] interface loopback 1

[ASBR-PE1-LoopBack1] ospf 1 prefix-sid index 30

[ASBR-PE1-LoopBack1] quit

# Create a routing policy and specify a label index value.

[ASBR-PE1]ip prefix-list 1 permit 2.2.2.9 32

[ASBR-PE1]route-policy policy1 permit node 1

[ASBR-PE1-route-policy-policy1-1] if-match ip address prefix-list 1

[ASBR-PE1-route-policy-policy1-1] apply label-index 20

[ASBR-PE1-route-policy-policy1-1] quit

# Start BGP on ASBR-PE 1. Enable the capability to exchange labeled routes with IBGP peer 2.2.2.9.

[ASBR-PE1] bgp 100

[ASBR-PE1-bgp-default] peer 2.2.2.9 as-number 100

[ASBR-PE1-bgp-default] peer 2.2.2.9 connect-interface loopback 1

[ASBR-PE1-bgp-default] address-family ipv4 unicast

[ASBR-PE1-bgp-default-ipv4] peer 2.2.2.9 enable

[ASBR-PE1-bgp-default-ipv4] peer 2.2.2.9 label-route-capability

# Redistribute routes from OSPF process 1 to BGP and apply the routing policy.

[ASBR-PE1-bgp-default-ipv4] import-route ospf 1 route-policy policy1

# Enable SR-MPLS.

[ASBR-PE1-bgp-default-ipv4] segment-routing mpls

[ASBR-PE1-bgp-default-ipv4] quit

# Enable the capability to exchange labeled routes with EBGP peer 11.0.0.1.

[ASBR-PE1-bgp-default] peer 11.0.0.1 as-number 600

[ASBR-PE1-bgp-default] address-family ipv4 unicast

[ASBR-PE1-bgp-default-ipv4] peer 11.0.0.1 enable

[ASBR-PE1-bgp-default-ipv4] peer 11.0.0.1 label-route-capability

5.     Configure ASBR-PE 2:

# Start OSPF on ASBR-PE 2, set the LSR ID, and enable MPLS and MPLS TE.

<ASBR-PE2> system-view

[ASBR-PE2] ospf 1 router-id 4.4.4.9

[ASBR-PE2-ospf-1] quit

[ASBR-PE2] interface hundredgige 1/0/4

[ASBR-PE2-HundredGigE1/0/4] mpls enable

[ASBR-PE2-HundredGigE1/0/4] quit

[ASBR-PE2] interface hundredgige 1/0/5

[ASBR-PE2-HundredGigE1/0/5] ospf 1 area 0

[ASBR-PE2-HundredGigE1/0/5] mpls enable

[ASBR-PE2-HundredGigE1/0/5] quit

[ASBR-PE2] interface loopback 1

[ASBR-PE2-LoopBack1] ip address 4.4.4.9 32

[ASBR-PE2-LoopBack1] ospf 1 area 0

[ASBR-PE2-LoopBack1] quit

[ASBR-PE2] mpls lsr-id 4.4.4.9

[ASBR-PE2] mpls te

[ASBR-PE2-te] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[ASBR-PE2] ospf 1

[ASBR-PE2-ospf-1] segment-routing mpls

[ASBR-PE2-ospf-1] quit

[ASBR-PE2] interface loopback 1

[ASBR-PE2-LoopBack1] ospf 1 prefix-sid index 40

[ASBR-PE2-LoopBack1] quit

# Create a routing policy and specify a label index value.

[ASBR-PE2]ip prefix-list 1 permit 5.5.5.9 32

[ASBR-PE2] route-policy policy1 permit node 1

[ASBR-PE2-route-policy-policy1-1] if-match ip address  prefix-list  1

[ASBR-PE2-route-policy-policy1-1] apply label-index 50

[ASBR-PE2-route-policy-policy1-1] quit

# Start BGP on ASBR-PE 2. Enable the capability to exchange labeled routes with IBGP peer 5.5.5.9.

[ASBR-PE2] bgp 600

[ASBR-PE2-bgp-default] peer 5.5.5.9 as-number 600

[ASBR-PE2-bgp-default] peer 5.5.5.9 connect-interface loopback 1

[ASBR-PE2-bgp-default] address-family ipv4 unicast

[ASBR-PE2-bgp-default-ipv4] peer 5.5.5.9 enable

[ASBR-PE2-bgp-default-ipv4] peer 5.5.5.9 label-route-capability

# Redistribute routes from OSPF process 1 to BGP and apply the routing policy.

[ASBR-PE2-bgp-default-ipv4] import-route ospf 1 route-policy policy1

# Enable SR-MPLS.

[ASBR-PE2-bgp-default-ipv4] segment-routing mpls

[ASBR-PE2-bgp-default-ipv4] quit

# Enable the capability to exchange labeled routes with EBGP peer 11.0.0.2.

[ASBR-PE2-bgp-default] peer 11.0.0.2 as-number 100

[ASBR-PE2-bgp-default] address-family ipv4 unicast

[ASBR-PE2-bgp-default-ipv4] peer 11.0.0.2 enable

[ASBR-PE2-bgp-default-ipv4] peer 11.0.0.2 label-route-capability

6.     Configure PE 2:

# Start OSPF on PE 2, set the LSR ID, and enable MPLS and MPLS TE.

<PE2> system-view

[PE2] ospf 1 router-id 5.5.5.9

[PE2-ospf-1] quit

[PE2] interface hundredgige 1/0/1

[PE2-HundredGigE1/0/1] mpls enable

[PE2-HundredGigE1/0/1] quit

[PE2] interface hundredgige 1/0/5

[PE2-HundredGigE1/0/5] ospf 1 area 0

[PE2-HundredGigE1/0/5] mpls enable

[PE2-HundredGigE1/0/5] quit

[PE2] interface loopback 1

[PE2-LoopBack1] ip address 5.5.5.9 32

[PE2-LoopBack1] ospf 1 area 0

[PE2-LoopBack1] quit

[PE2] mpls lsr-id 5.5.5.9

[PE2] mpls te

[PE2-te] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[PE2] ospf 1

[PE2-ospf-1] segment-routing mpls

[PE2-ospf-1] quit

[PE2] interface loopback 1

[PE2-LoopBack1] ospf 1 prefix-sid index 50

[PE2-LoopBack1] quit

# Create VPN instance vpn1, and configure the RD and route target attributes.

[PE2] ip vpn-instance vpn1

[PE2-vpn-instance-vpn1] route-distinguisher 11:11

[PE2-vpn-instance-vpn1] vpn-target 1:1 2:2 3:3 import-extcommunity

[PE2-vpn-instance-vpn1] vpn-target 3:3 export-extcommunity

[PE2-vpn-instance-vpn1] quit

# Associate HundredGigE 1/0/1 with VPN instance vpn1, and assign an IP address to the interface.

[PE2] interface hundredgige 1/0/1

[PE2-HundredGigE1/0/1] ip binding vpn-instance vpn1

[PE2-HundredGigE1/0/1] ip address 20.0.0.1 24

[PE2-HundredGigE1/0/1] quit

# Start BGP on PE 2.

[PE2] bgp 600

# Enable the capability to exchange labeled routes with IBGP peer 4.4.4.9.

[PE2-bgp-default] peer 4.4.4.9 as-number 600

[PE2-bgp-default] peer 4.4.4.9 connect-interface loopback 1

[PE2-bgp-default] address-family ipv4 unicast

[PE2-bgp-default-ipv4] peer 4.4.4.9 enable

[PE2-bgp-default-ipv4] peer 4.4.4.9 label-route-capability

# Enable SR-MPLS.

[PE2-bgp-default-ipv4] segment-routing mpls

[PE2-bgp-default-ipv4] quit

# Configure the maximum number of hops from PE 2 to EBGP peer 2.2.2.9 as 10.

[PE2-bgp-default] peer 2.2.2.9 as-number 100

[PE2-bgp-default] peer 2.2.2.9 connect-interface loopback 1

[PE2-bgp-default] peer 2.2.2.9 ebgp-max-hop 10

# Configure peer 2.2.2.9 as a VPNv4 peer.

[PE2-bgp-default] address-family vpnv4

[PE2-bgp-default-vpnv4] peer 2.2.2.9 enable

[PE2-bgp-default-vpnv4] quit

# Configure CE 2 as an EBGP peer and install the learned BGP route in the routing table of the VPN instance.

[PE2-bgp-default] ip vpn-instance vpn1

[PE2-bgp-default-vpn1] peer 20.0.0.2 as-number 65002

[PE2-bgp-default-vpn1] address-family ipv4 unicast

[PE2-bgp-default-ipv4-vpn1] peer 20.0.0.2 enable

7.     Configure CE 2:

# Assign an IP address to interface HundredGigE 1/0/1.

<CE2> system-view

[CE2] interface hundredgige 1/0/1

[CE2-HundredGigE1/0/1] ip address 20.0.0.2 24

[CE2-HundredGigE1/0/1] quit

# Establish an EBGP peer relationship with PE 2, and redistribute VPN routes.

[CE2] bgp 65002

[CE2-bgp-default] peer 20.0.0.1 as-number 600

[CE2-bgp-default] address-family ipv4 unicast

[CE2-bgp-default-ipv4] peer 20.0.0.1 enable

[CE2-bgp-default-ipv4] import-route direct

Verifying the configuration

# Execute the display ip routing-table command on CE 1 and CE 2 to verify that they have a route to each other. (Details not shown.)

# Verify that CE 1 and CE 2 can ping each other. (Details not shown.)

# Display MPLS LSP information on PE 1.

[PE1] display mpls lsp                                                              

FEC                         Proto       In/Out Label    Out Inter/NHLFE/LSINDEX

2.2.2.9/32                  BGP         -/16020         NHLFE1

5.5.5.9/32                  BGP         -/16050         NHLFE1

5.5.5.9                     BGP         -/-             HGE1/0/5

1.1.1.1                     Local       -/-             HGE1/0/5

2.2.2.9/32                  OSPF        16020/-         -

3.3.3.9/32                  OSPF        16030/3         HGE1/0/5

3.3.3.9/32                  OSPF        -/3             HGE1/0/5

Example: Configuring SR-MPLS inter-AS option C (II)

Network configuration

As shown in Figure 22, complete the following tasks:

·     Start OSPF and enable OSPF-based SR-MPLS on the PEs in the same AS.

·     Configure PE 1 and ASBR-PE 1 to exchange labeled IPv4 routes through IBGP. Enable BGP-based SR-MPLS.

·     Configure PE 2 and ASBR-PE 2 to exchange labeled IPv4 routes through IBGP. Enable BGP-based SR-MPLS.

·     Establish an MP-EBGP peer relationship between PE 1 and PE 2 to exchange VPNv4 routes.

·     Configure ASBR-PE 1 and ASBR-PE 2 to exchange  labeled IPv4 routes through EBGP. Enable BGP-based SR-MPLS.

·     Configure dynamic SID allocation on loopback interfaces of the devices. Then, establish an SRLSP based on the allocated SIDs and configure an MPLS TE tunnel over the SRLSP to transmit data.

Figure 22 Network diagram

Table 6 Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

PE 1

Loop1

2.2.2.9/32

PE 2

Loop1

5.5.5.9/32

 

HGE1/0/1

30.0.0.1/24

 

HGE1/0/1

20.0.0.1/24

 

HGE1/0/5

1.1.1.2/8

 

HGE1/0/5

9.1.1.2/8

ASBR-PE 1

Loop1

3.3.3.9/32

ASBR-PE 2

Loop1

4.4.4.9/32

 

HGE1/0/5

1.1.1.1/8

 

HGE1/0/5

9.1.1.1/8

 

HGE1/0/4

11.0.0.2/8

 

HGE1/0/4

11.0.0.1/8

CE 1

HGE1/0/1

30.0.0.2/24

CE 2

HGE1/0/1

20.0.0.2/24

 

Prerequisites

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

Procedure

1.     Configure IP addresses and masks for interfaces. (Details not shown.)

2.     Configure CE 1:

# Assign an IP address to interface HundredGigE 1/0/1.

<CE1> system-view

[CE1] interface hundredgige 1/0/1

[CE1-HundredGigE1/0/1] ip address 30.0.0.2 24

[CE1-HundredGigE1/0/1] quit

# Establish an EBGP peer relationship with PE 1, and redistribute VPN routes.

[CE1] bgp 65001

[CE1-bgp-default] peer 30.0.0.1 as-number 100

[CE1-bgp-default] address-family ipv4 unicast

[CE1-bgp-default-ipv4] peer 30.0.0.1 enable

[CE1-bgp-default-ipv4] import-route direct

[CE1-bgp-default-ipv4] quit

[CE1-bgp-default] quit

3.     Configure PE 1:

# Start OSPF on PE 1, set the LSR ID, and enable MPLS and MPLS TE.

<PE1> system-view

[PE1] ospf 1 router-id 2.2.2.9

[PE1-ospf-1] quit

[PE1] interface hundredgige 1/0/1

[PE1-HundredGigE1/0/1] ospf 1 area 0

[PE1-HundredGigE1/0/1] mpls enable

[PE1-HundredGigE1/0/1] quit

[PE1] interface loopback 1

[PE1-LoopBack1] ip address 2.2.2.9 32

[PE1-LoopBack1] ospf 1 area 0

[PE1-LoopBack1] quit

[PE1] mpls lsr-id 2.2.2.9

[PE1] mpls te

[PE1-te] quit

# Assign an IP address to HundredGigE 1/0/5. Start OSPF and enable MPLS on the interface.

[PE1] interface hundredgige 1/0/5

[PE1-HundredGigE1/0/5] ip address 1.1.1.2 255.0.0.0

[PE1-HundredGigE1/0/5] ospf 1 area 0

[PE1-HundredGigE1/0/5] mpls enable

[PE1-HundredGigE1/0/5] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[PE1] ospf 1

[PE1-ospf-1] segment-routing mpls

[PE1-ospf-1] quit

[PE1] interface loopback 1

[PE1-LoopBack1] ospf 1 prefix-sid index 20

[PE1-LoopBack1] quit

# Create VPN instance vpn1, and configure the RD and route target attributes.

[PE1] ip vpn-instance vpn1

[PE1-vpn-instance-vpn1] route-distinguisher 11:11

[PE1-vpn-instance-vpn1] vpn-target 1:1 2:2 3:3 import-extcommunity

[PE1-vpn-instance-vpn1] vpn-target 3:3 export-extcommunity

[PE1-vpn-instance-vpn1] quit

# Associate HundredGigE 1/0/1 with VPN instance vpn1, and assign an IP address to the interface.

[PE1] interface hundredgige 1/0/1

[PE1-HundredGigE1/0/1] ip binding vpn-instance vpn1

[PE1-HundredGigE1/0/1] ip address 30.0.0.1 24

[PE1-HundredGigE1/0/1] quit

# Create a routing policy and specify a label index value.

[PE1] route-policy policy1 permit node 1

[PE1-route-policy-policy1-1] apply label-index 20

[PE1-route-policy-policy1-1] quit

# Start BGP on PE 1.

[PE1] bgp 100

# Enable the capability to exchange labeled routes with IBGP peer 3.3.3.9.

[PE1-bgp-default] peer 3.3.3.9 as-number 100

[PE1-bgp-default] peer 3.3.3.9 connect-interface loopback 1

[PE1-bgp-default] address-family ipv4 unicast

[PE1-bgp-default-ipv4] peer 3.3.3.9 enable

[PE1-bgp-default-ipv4] peer 3.3.3.9 label-route-capability

# Enable SR-MPLS.

[PE1-bgp-default-ipv4] segment-routing mpls

# Redistribute the route of loopback interface 1 to BGP and apply the routing policy.

[PE1-bgp-default-ipv4] network 2.2.2.9 32 route-policy policy1

[PE1-bgp-default-ipv4] quit

# Configure the maximum number of hops from PE 1 to EBGP peer 5.5.5.9 as 10.

[PE1-bgp-default] peer 5.5.5.9 as-number 600

[PE1-bgp-default] peer 5.5.5.9 connect-interface loopback 1

[PE1-bgp-default] peer 5.5.5.9 ebgp-max-hop 10

# Configure peer 5.5.5.9 as a VPNv4 peer.

[PE1-bgp-default] address-family vpnv4

[PE1-bgp-default-vpnv4] peer 5.5.5.9 enable

[PE1-bgp-default-vpnv4] quit

# Configure CE 1 as an EBGP peer of PE 1 and install the learned BGP routes in the routing table of the VPN instance.

[PE1-bgp-default] ip vpn-instance vpn1

[PE1-bgp-default-vpn1] peer 30.0.0.2 as-number 65001

[PE1-bgp-default-vpn1] address-family ipv4 unicast

[PE1-bgp-default-ipv4-vpn1] peer 30.0.0.2 enable

4.     Configure ASBR-PE 1:

# Start OSPF on ASBR-PE 1, set the LSR ID, and enable MPLS and MPLS TE.

<ASBR-PE1> system-view

[ASBR-PE1] ospf 1 router-id 3.3.3.9

[ASBR-PE1-ospf-1] quit

[ASBR-PE1] interface hundredgige 1/0/4

[ASBR-PE1-HundredGigE1/0/4] mpls enable

[ASBR-PE1-HundredGigE1/0/4] quit

[ASBR-PE1] interface hundredgige 1/0/5

[ASBR-PE1-HundredGigE1/0/5] ospf 1 area 0

[ASBR-PE1-HundredGigE1/0/5] mpls enable

[ASBR-PE1-HundredGigE1/0/5] quit

[ASBR-PE1] interface loopback 1

[ASBR-PE1-LoopBack1] ip address 3.3.3.9 32

[ASBR-PE1-LoopBack1] ospf 1 area 0

[ASBR-PE1-LoopBack1] quit

[ASBR-PE1] mpls lsr-id 3.3.3.9

[ASBR-PE1] mpls te

[ASBR-PE1-te] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[ASBR-PE1] ospf 1

[ASBR-PE1-ospf-1] segment-routing mpls

[ASBR-PE1-ospf-1] quit

[ASBR-PE1] interface loopback 1

[ASBR-PE1-LoopBack1] ospf 1 prefix-sid index 30

[ASBR-PE1-LoopBack1] quit

# Start BGP on ASBR-PE 1. Enable the capability to exchange labeled routes with IBGP peer 2.2.2.9.

[ASBR-PE1] bgp 100

[ASBR-PE1-bgp-default] peer 2.2.2.9 as-number 100

[ASBR-PE1-bgp-default] peer 2.2.2.9 connect-interface loopback 1

[ASBR-PE1-bgp-default] address-family ipv4 unicast

[ASBR-PE1-bgp-default-ipv4] peer 2.2.2.9 enable

[ASBR-PE1-bgp-default-ipv4] peer 2.2.2.9 label-route-capability

# Enable SR-MPLS.

[ASBR-PE1-bgp-default-ipv4] segment-routing mpls

[ASBR-PE1-bgp-default-ipv4] quit

# Enable the capability to exchange labeled routes with EBGP peer 11.0.0.1.

[ASBR-PE1-bgp-default] peer 11.0.0.1 as-number 600

[ASBR-PE1-bgp-default] address-family ipv4 unicast

[ASBR-PE1-bgp-default-ipv4] peer 11.0.0.1 enable

[ASBR-PE1-bgp-default-ipv4] peer 11.0.0.1 label-route-capability

5.     Configure ASBR-PE 2:

# Start OSPF on ASBR-PE 2, set the LSR ID, and enable MPLS and MPLS TE.

<ASBR-PE2> system-view

[ASBR-PE2] ospf 1 router-id 4.4.4.9

[ASBR-PE2-ospf-1] quit

[ASBR-PE2] interface hundredgige 1/0/4

[ASBR-PE2-HundredGigE1/0/4] mpls enable

[ASBR-PE2-HundredGigE1/0/4] quit

[ASBR-PE2] interface hundredgige 1/0/5

[ASBR-PE2-HundredGigE1/0/5] ospf 1 area 0

[ASBR-PE2-HundredGigE1/0/5] mpls enable

[ASBR-PE2-HundredGigE1/0/5] quit

[ASBR-PE2] interface loopback 1

[ASBR-PE2-LoopBack1] ip address 4.4.4.9 32

[ASBR-PE2-LoopBack1] ospf 1 area 0

[ASBR-PE2-LoopBack1] quit

[ASBR-PE2] mpls lsr-id 4.4.4.9

[ASBR-PE2] mpls te

[ASBR-PE2-te] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[ASBR-PE2] ospf 1

[ASBR-PE2-ospf-1] segment-routing mpls

[ASBR-PE2-ospf-1] quit

[ASBR-PE2] interface loopback 1

[ASBR-PE2-LoopBack1] ospf 1 prefix-sid index 40

[ASBR-PE2-LoopBack1] quit

# Start BGP on ASBR-PE 2. Enable the capability to exchange labeled routes with IBGP peer 5.5.5.9.

[ASBR-PE2] bgp 600

[ASBR-PE2-bgp-default] peer 5.5.5.9 as-number 600

[ASBR-PE2-bgp-default] peer 5.5.5.9 connect-interface loopback 1

[ASBR-PE2-bgp-default] address-family ipv4 unicast

[ASBR-PE2-bgp-default-ipv4] peer 5.5.5.9 enable

[ASBR-PE2-bgp-default-ipv4] peer 5.5.5.9 label-route-capability

# Enable SR-MPLS.

[ASBR-PE2-bgp-default-ipv4] segment-routing mpls

[ASBR-PE2-bgp-default-ipv4] quit

# Enable the capability to exchange labeled routes with EBGP peer 11.0.0.2.

[ASBR-PE2-bgp-default] peer 11.0.0.2 as-number 100

[ASBR-PE2-bgp-default] address-family ipv4 unicast

[ASBR-PE2-bgp-default-ipv4] peer 11.0.0.2 enable

[ASBR-PE2-bgp-default-ipv4] peer 11.0.0.2 label-route-capability

6.     Configure PE 2:

# Start OSPF on PE 2, set the LSR ID, and enable MPLS and MPLS TE.

<PE2> system-view

[PE2] ospf 1 router-id 5.5.5.9

[PE2-ospf-1] quit

[PE2] interface hundredgige 1/0/1

[PE2-HundredGigE1/0/1] ospf 1 area 0

[PE2-HundredGigE1/0/1] mpls enable

[PE2-HundredGigE1/0/1] quit

[PE2] interface loopback 1

[PE2-LoopBack1] ip address 5.5.5.9 32

[PE2-LoopBack1] ospf 1 area 0

[PE2-LoopBack1] quit

[PE2] mpls lsr-id 5.5.5.9

[PE2] mpls te

[PE2-te] quit

# Assign an IP address to HundredGigE 1/0/5. Start OSPF and enable MPLS on the interface.

[PE2] interface hundredgige 1/0/5

[PE2-HundredGigE1/0/5] ip address 9.1.1.2 255.0.0.0

[PE2-HundredGigE1/0/5] ospf 1 area 0

[PE2-HundredGigE1/0/5] mpls enable

[PE2-HundredGigE1/0/5] quit

# Enable SR-MPLS in OSPF view and configure an OSPF prefix SID.

[PE2] ospf 1

[PE2-ospf-1] segment-routing mpls

[PE2-ospf-1] quit

[PE2] interface loopback 1

[PE2-LoopBack1] ospf 1 prefix-sid index 50

[PE2-LoopBack1] quit

# Create VPN instance vpn1, and configure the RD and route target attributes.

[PE2] ip vpn-instance vpn1

[PE2-vpn-instance-vpn1] route-distinguisher 11:11

[PE2-vpn-instance-vpn1] vpn-target 1:1 2:2 3:3 import-extcommunity

[PE2-vpn-instance-vpn1] vpn-target 3:3 export-extcommunity

[PE2-vpn-instance-vpn1] quit

# Associate HundredGigE 1/0/1 with VPN instance vpn1, and assign an IP address to the interface.

[PE2] interface hundredgige 1/0/1

[PE2-HundredGigE1/0/1] ip binding vpn-instance vpn1

[PE2-HundredGigE1/0/1] ip address 20.0.0.1 24

[PE2-HundredGigE1/0/1] quit

# Create a routing policy and specify a label index value.

[PE2] route-policy policy1 permit node 1

[PE2-route-policy-policy1-1] apply label-index 50

[PE2-route-policy-policy1-1] quit

# Start BGP on PE 2. Enable the capability to exchange labeled routes with IBGP peer 4.4.4.9.

[PE2] bgp 600

[PE2-bgp-default] peer 4.4.4.9 as-number 600

[PE2-bgp-default] peer 4.4.4.9 connect-interface loopback 1

[PE2-bgp-default] address-family ipv4 unicast

[PE2-bgp-default-ipv4] peer 4.4.4.9 enable

[PE2-bgp-default-ipv4] peer 4.4.4.9 label-route-capability

# Enable SR-MPLS.

[PE2-bgp-default-ipv4] segment-routing mpls

# Redistribute the route of loopback interface 1 to BGP and apply the routing policy.

[PE2-bgp-default-ipv4] network 5.5.5.9 32 route-policy policy1

[PE2-bgp-default-ipv4] quit

# Configure the maximum number of hops from PE 2 to EBGP peer 2.2.2.9 as 10.

[PE2-bgp-default] peer 2.2.2.9 as-number 100

[PE2-bgp-default] peer 2.2.2.9 connect-interface loopback 1

[PE2-bgp-default] peer 2.2.2.9 ebgp-max-hop 10

# Configure peer 2.2.2.9 as a VPNv4 peer.

[PE2-bgp-default] address-family vpnv4

[PE2-bgp-default-vpnv4] peer 2.2.2.9 enable

[PE2-bgp-default-vpnv4] quit

# Configure CE 2 as an EBGP peer of PE 2 and install the learned BGP routes in the routing table of the VPN instance.

[PE2-bgp-default] ip vpn-instance vpn1

[PE2-bgp-default-vpn1] peer 20.0.0.2 as-number 65001

[PE2-bgp-default-vpn1] address-family ipv4 unicast

[PE2-bgp-default-ipv4-vpn1] peer 20.0.0.2 enable

7.     Configure CE 2:

# Assign an IP address to interface HundredGigE 1/0/1.

<CE2> system-view

[CE2] interface hundredgige 1/0/1

[CE2-HundredGigE1/0/1] ip address 20.0.0.2 24

[CE2-HundredGigE1/0/1] quit

# Establish an EBGP peer relationship with PE 2, and redistribute VPN routes.

[CE2] bgp 65002

[CE2-bgp-default] peer 20.0.0.1 as-number 600

[CE2-bgp-default] address-family ipv4 unicast

[CE2-bgp-default-ipv4] peer 20.0.0.1 enable

[CE2-bgp-default-ipv4] import-route direct

[CE2-bgp-default-ipv4] quit

[CE2-bgp-default] quit

Verifying the configuration

# Execute the display ip routing-table command on CE 1 and CE 2 to verify that they have a route to each other. (Details not shown.)

# Verify that CE 1 and CE 2 can ping each other. (Details not shown.)

# Display MPLS LSP information on PE1.

[PE1] display mpls lsp

FEC                         Proto       In/Out Label    Out Inter/NHLFE/LSINDEX

2.2.2.9/32                  BGP         3/-             -

5.5.5.9/32                  BGP         -/16050         NHLFE1

5.5.5.9                     BGP         -/-             HGE1/0/5

1.1.1.1                     Local       -/-             HGE1/0/5

2.2.2.9/32                  OSPF        16020/-         -

3.3.3.9/32                  OSPF        16030/3         HGE1/0/5

3.3.3.9/32                  OSPF        -/3             HGE1/0/5

Example: Configuring SR-MPLS to LDP (IS-IS)

Network configuration

As shown in Figure 23, complete the following tasks so Router A and Router C can communicate with each other:

·     Configure Router A, Router B, and Router C to run IS-IS.

·     Configure Router A and Router B to run SR-MPLS and establish an SRLSP between Router A and Router B.

·     Configure Router B and Router C to run LDP to establish a dynamic LDP LSP between them.

·     Configure Router B as the SRMS, map the prefix address of the LDP network to an SID, and advertise the mapping to Router A.

Figure 23 Network diagram

Table 7 Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

Router A

Loop1

1.1.1.1/32

Router B

Loop1

2.2.2.2/32

 

HGE1/0/1

10.0.0.1/24

 

HGE1/0/1

10.0.0.2/24

Router C

Loop1

3.3.3.3/32

 

HGE1/0/2

11.0.0.1/24

 

HGE1/0/1

11.0.0.2/24

 

 

 

 

Prerequisites

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

Procedure

1.     Configure IP addresses and masks for interfaces. (Details not shown.)

2.     Configure Router A:

# Configure IS-IS to achieve network level connectivity and set the IS-IS cost style to wide.

<RouterA> system-view

[RouterA] isis 1

[RouterA-isis-1] network-entity 00.0000.0000.0001.00

[RouterA-isis-1] cost-style wide

[RouterA-isis-1] quit

[RouterA] interface hundredgige 1/0/1

[RouterA-HundredGigE1/0/1] isis enable 1

[RouterA-HundredGigE1/0/1] quit

[RouterA] interface loopback 1

[RouterA-LoopBack1] isis enable 1

[RouterA-LoopBack1] quit

# Configure the LSR ID.

[RouterA] mpls lsr-id 1.1.1.1

# Enable SR-MPLS.

[RouterA] isis 1

[RouterA-isis-1] address-family ipv4

[RouterA-isis-1-ipv4] segment-routing mpls

[RouterA-isis-1-ipv4] quit

# Configure the SRGB.

[RouterA-isis-1] segment-routing global-block 16000 16999

[RouterA-isis-1] quit

3.     Configure Router B:

# Configure IS-IS to achieve network level connectivity and set the IS-IS cost style to wide.

<RouterB> system-view

[RouterB] isis 1

[RouterB-isis-1] network-entity 00.0000.0000.0002.00

[RouterB-isis-1] cost-style wide

[RouterB-isis-1] quit

[RouterB] interface hundredgige 1/0/1

[RouterB-HundredGigE1/0/1] isis enable 1

[RouterB-HundredGigE1/0/1] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] isis enable 1

[RouterB-HundredGigE1/0/2] quit

[RouterB] interface loopback 1

[RouterB-LoopBack1] isis enable 1

[RouterB-LoopBack1] quit

# Configure the LSR ID.

[RouterB] mpls lsr-id 2.2.2.2

# Configure LDP.

[RouterB] mpls ldp

[RouterB-ldp] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] mpls enable

[RouterB-HundredGigE1/0/2] mpls ldp enable

[RouterB-HundredGigE1/0/2] quit

# Enable SR-MPLS.

[RouterB] isis 1

[RouterB-isis-1] address-family ipv4

[RouterB-isis-1-ipv4] segment-routing mpls

[RouterB-isis-1-ipv4] quit

# Configure the SRGB.

[RouterB-isis-1] segment-routing global-block 17000 17999

# Configure the IGP to advertise locally configured prefix-SID mappings.

[RouterB-isis-1] address-family ipv4

[RouterB-isis-1-ipv4] segment-routing mapping-server advertise-local

[RouterB-isis-1-ipv4] quit

[RouterB-isis-1] quit

# Configure a prefix-SID mapping.

[RouterB] segment-routing

[RouterB-segment-routing] mapping-server prefix-sid-map 3.3.3.3 32 100

[RouterB-segment-routing] quit

4.     Configure Router C:

# Configure IS-IS to achieve network level connectivity and set the IS-IS cost style to wide.

<RouterC> system-view

[RouterC] isis 1

[RouterC-isis-1] network-entity 00.0000.0000.0003.00

[RouterC-isis-1] cost-style wide

[RouterC-isis-1] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] isis enable 1

[RouterC-HundredGigE1/0/1] quit

[RouterC] interface loopback 1

[RouterC-LoopBack1] isis enable 1

[RouterC-LoopBack1] quit

# Configure the LSR ID.

[RouterC] mpls lsr-id 3.3.3.3

# Configure LDP.

[RouterC] mpls ldp

[RouterC-ldp] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] mpls enable

[RouterC-HundredGigE1/0/1] mpls ldp enable

[RouterC-HundredGigE1/0/1] quit

Verifying the configuration

# Display IS-IS SRLSP information on Router A.

[RouterA] display mpls lsp protocol isis

FEC                         Proto       In/Out Label    Out Inter/NHLFE/LSINDEX

3.3.3.3/32                  ISIS        16100/17100     HGE1/0/1

3.3.3.3/32                  ISIS        -/17100         HGE1/0/1

The output shows that the outgoing label of the IS-IS SRLSP entry for Router C is using the SID assigned to Router C.

Example: Configuring SR-MPLS to LDP (OSPF)

Network configuration

As shown in Figure 24, complete the following tasks so Router A and Router C can communicate with each other:

·     Configure Router A, Router B, and Router C to run OSPF.

·     Configure Router A and Router B to run SR-MPLS and establish an SRLSP between Router A and Router B.

·     Configure Router B and Router C to run LDP to establish a dynamic LDP LSP between them.

·     Configure Router B as the SRMS, map the prefix address of the LDP network to an SID, and advertise the mapping to Router A.

Figure 24 Network diagram

Table 8 Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

Router A

Loop1

1.1.1.1/32

Router B

Loop1

2.2.2.2/32

 

HGE1/0/1

10.0.0.1/24

 

HGE1/0/1

10.0.0.2/24

Router C

Loop1

3.3.3.3/32

 

HGE1/0/2

11.0.0.1/24

 

HGE1/0/1

11.0.0.2/24

 

 

 

 

Prerequisites

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

Procedure

1.     Configure IP addresses and masks for interfaces. (Details not shown.)

2.     Configure Router A:

# Configure OSPF to achieve network level connectivity.

<RouterA> system-view

[RouterA] ospf 1 router-id 1.1.1.1

[RouterA-ospf-1] quit

[RouterA] interface hundredgige 1/0/1

[RouterA-HundredGigE1/0/1] ospf 1 area 0

[RouterA-HundredGigE1/0/1] quit

[RouterA] interface loopback 1

[RouterA-LoopBack1] ospf 1 area 0

[RouterA-LoopBack1] quit

# Configure the LSR ID.

[RouterA] mpls lsr-id 1.1.1.1

# Enable SR-MPLS.

[RouterA] ospf 1

[RouterA-ospf-1] segment-routing mpls

[RouterA-ospf-1] quit

# Configure the SRGB.

[RouterA-ospf-1] segment-routing global-block 16000 16999

[RouterA-ospf-1] quit

3.     Configure Router B:

# Configure OSPF to achieve network level connectivity.

<RouterB> system-view

[RouterB] ospf 1 router-id 2.2.2.2

[RouterB-ospf-1] quit

[RouterB] interface hundredgige 1/0/1

[RouterB-HundredGigE1/0/1] ospf 1 area 0

[RouterB-HundredGigE1/0/1] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] ospf 1 area 0

[RouterB-HundredGigE1/0/2] quit

[RouterB] interface loopback 1

[RouterB-LoopBack1] ospf 1 area 0

[RouterB-LoopBack1] quit

# Configure the LSR ID.

[RouterB] mpls lsr-id 2.2.2.2

# Configure LDP.

[RouterB] mpls ldp

[RouterB-ldp] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] mpls enable

[RouterB-HundredGigE1/0/2] mpls ldp enable

[RouterB-HundredGigE1/0/2] quit

# Enable SR-MPLS.

[RouterB] ospf 1

[RouterB-ospf-1] segment-routing mpls

# Configure the SRGB.

[RouterB-ospf-1] segment-routing global-block 17000 17999

# Configure the IGP to advertise locally configured prefix-SID mappings.

[RouterB-ospf-1] segment-routing mapping-server advertise-local

[RouterB-ospf-1] quit

# Configure a prefix-SID mapping.

[RouterB] segment-routing

[RouterB-segment-routing] mapping-server prefix-sid-map 3.3.3.3 32 100

[RouterB-segment-routing] quit

4.     Configure Router C:

# Configure OSPF to achieve network level connectivity.

<RouterC> system-view

[RouterC] ospf 1 router-id 3.3.3.3

[RouterC-ospf-1] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] ospf 1 area 0

[RouterC-HundredGigE1/0/1] quit

[RouterC] interface loopback 1

[RouterC-LoopBack1] ospf 1 area 0

[RouterC-LoopBack1] quit

# Configure the LSR ID.

[RouterC] mpls lsr-id 3.3.3.3

# Configure LDP.

[RouterC] mpls ldp

[RouterC-ldp] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] mpls enable

[RouterC-HundredGigE1/0/1] mpls ldp enable

[RouterC-HundredGigE1/0/1] quit

Verifying the configuration

# Display OSPF SRLSP information on Router A.

[RouterA] display mpls lsp protocol ospf

FEC                         Proto       In/Out Label    Out Inter/NHLFE/LSINDEX

3.3.3.3/32                  OSPF        16100/17100     HGE1/0/1

3.3.3.3/32                  OSPF        -/17100         HGE1/0/1

The output shows that the outgoing label of the OSPF SRLSP entry for Router C is using the SID assigned to Router C.

Example: Configuring SR-MPLS over LDP

Network configuration

As shown in Figure 25, complete the following tasks so the two SR networks can communicate across the LDP network:

·     Configure Router A, Router B, Router C, Router D, and Router E to run IS-IS.

·     Configure Router B, Router C, and Router D to run LDP.

·     Configure Router A, Router B, Router D, and Router E to run SR-MPLS.

Figure 25 Network diagram

Table 9 Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

Router A

Loop1

1.1.1.1/32

Router B

Loop1

2.2.2.2/32

 

HGE1/0/1

10.0.0.1/24

 

HGE1/0/1

10.0.0.2/24

Router C

Loop1

3.3.3.3/32

 

HGE1/0/2

11.0.0.1/24

 

HGE1/0/1

11.0.0.2/24

Router D

Loop1

4.4.4.4/32

 

HGE1/0/2

12.0.0.1/24

 

HGE1/0/1

12.0.0.2/24

Router E

Loop1

5.5.5.5/32

 

HGE1/0/2

13.0.0.1/24

 

HGE1/0/1

13.0.0.2/24

 

 

 

 

Prerequisites

Configure IP addresses and masks for interfaces.

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

Procedure

1.     Configure IS-IS on the routers to achieve network level connectivity and set the IS-IS cost style to wide:

# Configure Router A.

<RouterA> system-view

[RouterA] isis 1

[RouterA-isis-1] network-entity 00.0000.0000.0001.00

[RouterA-isis-1] cost-style wide

[RouterA-isis-1] quit

[RouterA] interface hundredgige 1/0/1

[RouterA-HundredGigE1/0/1] isis enable 1

[RouterA-HundredGigE1/0/1] quit

[RouterA] interface loopback 1

[RouterA-LoopBack1] isis enable 1

[RouterA-LoopBack1] quit

# Configure Router B.

<RouterB> system-view

[RouterB] isis 1

[RouterB-isis-1] network-entity 00.0000.0000.0002.00

[RouterB-isis-1] cost-style wide

[RouterB-isis-1] quit

[RouterB] interface hundredgige 1/0/1

[RouterB-HundredGigE1/0/1] isis enable 1

[RouterB-HundredGigE1/0/1] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] isis enable 1

[RouterB-HundredGigE1/0/2] quit

[RouterB] interface loopback 1

[RouterB-LoopBack1] isis enable 1

[RouterB-LoopBack1] quit

# Configure Router C.

<RouterC> system-view

[RouterC] isis 1

[RouterC-isis-1] network-entity 00.0000.0000.0003.00

[RouterC-isis-1] cost-style wide

[RouterC-isis-1] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] isis enable 1

[RouterC-HundredGigE1/0/1] quit

[RouterC] interface hundredgige 1/0/2

[RouterC-HundredGigE1/0/2] isis enable 1

[RouterC-HundredGigE1/0/2] quit

[RouterC] interface loopback 1

[RouterC-LoopBack1] isis enable 1

[RouterC-LoopBack1] quit

# Configure Router D.

<RouterD> system-view

[RouterD] isis 1

[RouterD-isis-1] network-entity 00.0000.0000.0004.00

[RouterD-isis-1] cost-style wide

[RouterD-isis-1] quit

[RouterD] interface hundredgige 1/0/1

[RouterD-HundredGigE1/0/1] isis enable 1

[RouterD-HundredGigE1/0/1] quit

[RouterD] interface hundredgige 1/0/2

[RouterD-HundredGigE1/0/2] isis enable 1

[RouterD-HundredGigE1/0/2] quit

[RouterD] interface loopback 1

[RouterD-LoopBack1] isis enable 1

[RouterD-LoopBack1] quit

# Configure Router E.

<RouterE> system-view

[RouterE] isis 1

[RouterE-isis-1] network-entity 00.0000.0000.0005.00

[RouterE-isis-1] cost-style wide

[RouterE-isis-1] quit

[RouterE] interface hundredgige 1/0/1

[RouterE-HundredGigE1/0/1] isis enable 1

[RouterE-HundredGigE1/0/1] quit

[RouterE] interface loopback 1

[RouterE-LoopBack1] isis enable 1

[RouterE-LoopBack1] quit

2.     Configure LSR IDs on the routers:

# Configure Router A.

[RouterA] mpls lsr-id 1.1.1.1

# Configure Router B.

[RouterB] mpls lsr-id 2.2.2.2

# Configure Router C.

[RouterC] mpls lsr-id 3.3.3.3

# Configure Router D.

[RouterD] mpls lsr-id 4.4.4.4

# Configure Router E.

[RouterE] mpls lsr-id 5.5.5.5

3.     Configure LDP on Router B, Router C, and Router D:

# Configure Router B.

[RouterB] mpls ldp

[RouterB-ldp] quit

[RouterB] interface hundredgige 1/0/2

[RouterB-HundredGigE1/0/2] mpls enable

[RouterB-HundredGigE1/0/2] mpls ldp enable

[RouterB-HundredGigE1/0/2] quit

# Configure Router C.

[RouterC] mpls ldp

[RouterC-ldp] quit

[RouterC] interface hundredgige 1/0/1

[RouterC-HundredGigE1/0/1] mpls enable

[RouterC-HundredGigE1/0/1] mpls ldp enable

[RouterC-HundredGigE1/0/1] quit

[RouterC] interface hundredgige 1/0/2

[RouterC-HundredGigE1/0/2] mpls enable

[RouterC-HundredGigE1/0/2] mpls ldp enable

[RouterC-HundredGigE1/0/2] quit

# Configure Router D.

[RouterD] mpls ldp

[RouterD-ldp] quit

[RouterD] interface hundredgige 1/0/1

[RouterD-HundredGigE1/0/1] mpls enable

[RouterD-HundredGigE1/0/1] mpls ldp enable

[RouterD-HundredGigE1/0/1] quit

4.     Enable SR-MPLS on Router A, Router B, Router D, and Router E:

# Configure Router A.

[RouterA] isis 1

[RouterA-isis-1] address-family ipv4

[RouterA-isis-1-ipv4] segment-routing mpls

[RouterA-isis-1-ipv4] quit

# Configure Router B.

[RouterB] isis 1

[RouterB-isis-1] address-family ipv4

[RouterB-isis-1-ipv4] segment-routing mpls

[RouterB-isis-1-ipv4] quit

# Configure Router D.

[RouterD] isis 1

[RouterD-isis-1] address-family ipv4

[RouterD-isis-1-ipv4] segment-routing mpls

[RouterD-isis-1-ipv4] quit

# Configure Router E.

[RouterE] isis 1

[RouterE-isis-1] address-family ipv4

[RouterE-isis-1-ipv4] segment-routing mpls

[RouterE-isis-1-ipv4] quit

5.     Configure SRGBs on Router A, Router B, Router D, and Router E:

# Configure Router A.

[RouterA-isis-1] segment-routing global-block 16000 16999

[RouterA-isis-1] quit

# Configure Router B.

[RouterB-isis-1] segment-routing global-block 17000 17999

[RouterB-isis-1] quit

# Configure Router D.

[RouterD-isis-1] segment-routing global-block 18000 18999

[RouterD-isis-1] quit

# Configure Router E.

[RouterE-isis-1] segment-routing global-block 19000 19999

[RouterE-isis-1] quit

6.     Configure IS-IS prefix SIDs for Router A, Router B, Router D, and Router E:

# Configure Router A.

[RouterA] interface loopback 1

[RouterA-LoopBack1] isis prefix-sid index 10

[RouterA-LoopBack1] quit

# Configure Router B.

[RouterB] interface loopback 1

[RouterB-LoopBack1] isis prefix-sid index 20

[RouterB-LoopBack1] quit

# Configure Router D.

[RouterD] interface loopback 1

[RouterD-LoopBack1] isis prefix-sid index 40

[RouterD-LoopBack1] quit

# Configure Router E.

[RouterE] interface loopback 1

[RouterE-LoopBack1] isis prefix-sid index 50

[RouterE-LoopBack1] quit

Verifying the configuration

# Display LDP LSP information on Router B.

[RouterB] display mpls ldp lsp

Status Flags: * - stale, L - liberal, B - backup, N/A - unavailable

FECs: 5           Ingress: 3           Transit: 3           Egress: 2

 

FEC                In/Out Label        Nexthop         OutInterface

1.1.1.1/32         2173/-

                   -/2173(L)

2.2.2.2/32         3/-

                   -/2175(L)

3.3.3.3/32         -/3                 11.0.0.2        HGE1/0/2

                   2175/3              11.0.0.2        HGE1/0/2

4.4.4.4/32         -/2174              11.0.0.2        HGE1/0/2

                   2174/2174           11.0.0.2        HGE1/0/2

5.5.5.5/32         -/2172              11.0.0.2        HGE1/0/2

                   2172/2172           11.0.0.2        HGE1/0/2

# Display IS-IS SRLSP information on Router B.

[RouterB] display mpls lsp protocol isis

FEC                         Proto       In/Out Label    Out Inter/NHLFE/LSINDEX

1.1.1.1/32                  ISIS        17010/3         HGE1/0/1

1.1.1.1/32                  ISIS        -/3             HGE1/0/1

2.2.2.2/32                  ISIS        17020/-         -

4.4.4.4/32                  ISIS        17040/2174      HGE1/0/2

4.4.4.4/32                  ISIS        -/2174          HGE1/0/2

5.5.5.5/32                  ISIS        17050/2172      HGE1/0/2

5.5.5.5/32                  ISIS        -/2172          HGE1/0/2

The output shows that the IS-IS SRLSP entries for Router D and Router E are using LDP outgoing labels.

Example: Configuring IS-IS TI-LFA FRR

Network configuration

As shown in Figure 26, complete the following tasks to implement TI-LFA FRR:

·     Configure IS-IS on Device A, Device B, and Device C to achieve network level connectivity.

·     Configure SR-MPLS on Device A, Device B, and Device C.

·     Configure TI-LFA FRR to remove the loop that exists on Link B and to implement fast traffic switchover to Link B when Link A fails.

Figure 26 Network diagram

Table 10 Interface and IP address assignment

Device

Interface

IP address

Device

Interface

IP address

Device A

Loop1

1.1.1.1/32

Device B

Loop1

2.2.2.2/32

 

HGE1/0/1

12.12.12.1/24

 

HGE1/0/1

24.24.24.1/24

 

HGE1/0/2

13.13.13.1/24

 

HGE1/0/2

13.13.13.2/24

Device C

Loop1

3.3.3.3/32

 

 

 

 

HGE1/0/1

12.12.12.2/24

 

 

 

 

HGE1/0/2

24.24.24.2/24

 

 

 

 

Prerequisites

Configure IP addresses and masks for interfaces.

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

Procedure

1.     Configure IS-IS on the switches to achieve network level connectivity and set the IS-IS cost style to wide:

# Configure Device A.

<DeviceA> system-view

[DeviceA] isis 1

[DeviceA-isis-1] network-entity 00.0000.0000.0001.00

[DeviceA-isis-1] cost-style wide

[DeviceA-isis-1] quit

[DeviceA] interface hundredgige 1/0/1

[DeviceA-HundredGigE1/0/1] isis enable 1

[DeviceA-HundredGigE1/0/1] isis cost 10

[DeviceA-HundredGigE1/0/1] quit

[DeviceA] interface hundredgige 1/0/2

[DeviceA-HundredGigE1/0/2] isis enable 1

[DeviceA-HundredGigE1/0/2] isis cost 10

[DeviceA-HundredGigE1/0/2] quit

[DeviceA] interface loopback 1

[DeviceA-LoopBack1] isis enable 1

[DeviceA-LoopBack1] quit

# Configure Device B.

<DeviceB> system-view

[DeviceB] isis 1

[DeviceB-isis-1] network-entity 00.0000.0000.0002.00

[DeviceB-isis-1] cost-style wide

[DeviceB-isis-1] quit

[DeviceB] interface hundredgige 1/0/1

[DeviceB-HundredGigE1/0/1] isis enable 1

[DeviceB-HundredGigE1/0/1] isis cost 20

[DeviceB-HundredGigE1/0/1] quit

[DeviceB] interface hundredgige 1/0/2

[DeviceB-HundredGigE1/0/2] isis enable 1

[DeviceB-HundredGigE1/0/2] isis cost 10

[DeviceB-HundredGigE1/0/2] quit

[DeviceB] interface loopback 1

[DeviceB-LoopBack1] isis enable 1

[DeviceB-LoopBack1] quit

# Configure Device C.

<DeviceC> system-view

[DeviceC] isis 1

[DeviceC-isis-1] network-entity 00.0000.0000.0003.00

[DeviceC-isis-1] cost-style wide

[DeviceC-isis-1] quit

[DeviceC] interface hundredgige 1/0/1

[DeviceC-HundredGigE1/0/1] isis enable 1

[DeviceC-HundredGigE1/0/1] isis cost 10

[DeviceC-HundredGigE1/0/1] quit

[DeviceC] interface hundredgige 1/0/2

[DeviceC-HundredGigE1/0/2] isis enable 1

[DeviceC-HundredGigE1/0/2] isis cost 20

[DeviceC-HundredGigE1/0/2] quit

[DeviceC] interface loopback 1

[DeviceC-LoopBack1] isis enable 1

[DeviceC-LoopBack1] quit

2.     Configure MPLS TE:

# Configure Device A.

[DeviceA] mpls lsr-id 1.1.1.1

[DeviceA] mpls te

[DeviceA-te] quit

[DeviceA] interface hundredgige 1/0/1

[DeviceA-HundredGigE1/0/1] mpls enable

[DeviceA-HundredGigE1/0/1] mpls te enable

[DeviceA-HundredGigE1/0/1] quit

[DeviceA] interface hundredgige 1/0/2

[DeviceA-HundredGigE1/0/2] mpls enable

[DeviceA-HundredGigE1/0/2] mpls te enable

[DeviceA-HundredGigE1/0/2] quit

# Configure Device B.

[DeviceB] mpls lsr-id 2.2.2.2

[DeviceB] mpls te

[DeviceB-te] quit

[DeviceB] interface hundredgige 1/0/1

[DeviceB-HundredGigE1/0/1] mpls enable

[DeviceB-HundredGigE1/0/1] mpls te enable

[DeviceB-HundredGigE1/0/1] quit

[DeviceB] interface hundredgige 1/0/2

[DeviceB-HundredGigE1/0/2] mpls enable

[DeviceB-HundredGigE1/0/2] mpls te enable

[DeviceB-HundredGigE1/0/2] quit

# Configure Device C.

[DeviceC] mpls lsr-id 3.3.3.3

[DeviceC] mpls te

[DeviceC-te] quit

[DeviceC] interface hundredgige 1/0/1

[DeviceC-HundredGigE1/0/1] mpls enable

[DeviceC-HundredGigE1/0/1] mpls te enable

[DeviceC-HundredGigE1/0/1] quit

[DeviceC] interface hundredgige 1/0/2

[DeviceC-HundredGigE1/0/2] mpls enable

[DeviceC-HundredGigE1/0/2] mpls te enable

[DeviceC-HundredGigE1/0/2] quit

3.     Enable SR-MPLS and SR-MPLS adjacency label allocation:

# Configure Device A.

[DeviceA] isis 1

[DeviceA-isis-1] address-family ipv4

[DeviceA-isis-1-ipv4] segment-routing mpls

[DeviceA-isis-1-ipv4] segment-routing adjacency enable

[DeviceA-isis-1-ipv4] quit

# Configure Device B.

[DeviceB] isis 1

[DeviceB-isis-1] address-family ipv4

[DeviceB-isis-1-ipv4] segment-routing mpls

[DeviceB-isis-1-ipv4] segment-routing adjacency enable

[DeviceB-isis-1-ipv4] quit

# Configure Device C.

[DeviceC] isis 1

[DeviceC-isis-1] address-family ipv4

[DeviceC-isis-1-ipv4] segment-routing mpls

[DeviceC-isis-1-ipv4] segment-routing adjacency enable

[DeviceC-isis-1-ipv4] quit

4.     Configure the SRGBs:

# Configure Device A.

[DeviceA-isis-1] segment-routing global-block 16000 16999

[DeviceA-isis-1] quit

# Configure Device B.

[DeviceB-isis-1] segment-routing global-block 17000 17999

[DeviceB-isis-1] quit

# Configure Device C.

[DeviceC-isis-1] segment-routing global-block 18000 18999

[DeviceC-isis-1] quit

5.     Configure IS-IS prefix SIDs for Device A, Device B, and Device C:

# Configure Device A.

[DeviceA] interface loopback 1

[DeviceA-LoopBack1] isis prefix-sid index 10

[DeviceA-LoopBack1] quit

# Configure Device B.

[DeviceB] interface loopback 1

[DeviceB-LoopBack1] isis prefix-sid index 20

[DeviceB-LoopBack1] quit

# Configure Device C.

[DeviceC] interface loopback 1

[DeviceC-LoopBack1] isis prefix-sid index 30

[DeviceC-LoopBack1] quit

6.     Configure TI-LFA FRR:

# Configure Device A.

[DeviceA] isis 1

[DeviceA-isis-1] address-family ipv4

[DeviceA-isis-1-ipv4] fast-reroute lfa

[DeviceA-isis-1-ipv4] fast-reroute ti-lfa

[DeviceA-isis-1-ipv4] fast-reroute microloop-avoidance enable

[DeviceA-isis-1-ipv4] segment-routing microloop-avoidance enable

[DeviceA-isis-1-ipv4] quit

[DeviceA-isis-1] quit

# Configure Device B.

[DeviceB] isis 1

[DeviceB-isis-1] address-family ipv4

[DeviceB-isis-1-ipv4] fast-reroute lfa

[DeviceB-isis-1-ipv4] fast-reroute ti-lfa

[DeviceB-isis-1-ipv4] fast-reroute microloop-avoidance enable

[DeviceB-isis-1-ipv4] segment-routing microloop-avoidance enable

[DeviceB-isis-1-ipv4] quit

[DeviceB-isis-1] quit

# Configure Device C.

[DeviceC] isis 1

[DeviceC-isis-1] address-family ipv4

[DeviceC-isis-1-ipv4] fast-reroute lfa

[DeviceC-isis-1-ipv4] fast-reroute ti-lfa

[DeviceC-isis-1-ipv4] fast-reroute microloop-avoidance enable

[DeviceC-isis-1-ipv4] segment-routing microloop-avoidance enable

[DeviceC-isis-1-ipv4] quit

[DeviceC-isis-1] quit

Verifying the configuration

# Display IPv4 IS-IS routing information for 2.2.2.2/32.

[DeviceA] display isis route ipv4 2.2.2.2 32 verbose level-1 1

 

                         Route information for IS-IS(1)

                         -----------------------------

 

                         Level-1 IPv4 Forwarding Table

                         -----------------------------

 

IPv4 Dest : 2.2.2.2/32          Int. Cost  : 10               Ext. Cost  : NULL

Admin Tag : -                   Src Count  : 1                Flag       : R/L/-

InLabel   : 16020               InLabel Flag: -/N/-/-/-/-

NextHop   :                     Interface  :                  ExitIndex  :

    13.13.13.2                          HGE1/0/2                   0x00000103

Nib ID    : 0x14000005          OutLabel   : 17020            OutLabelFlag: I

LabelSrc  : SR

TI-LFA:

  Interface : HGE1/0/1

  BkNextHop : 12.12.12.2         LsIndex    : 0x00000002

  Backup label stack(top->bottom): {18030, 2175}

  Route label: 17020

 

      Flags: D-Direct, R-Added to Rib, L-Advertised in LSPs, U-Up/Down Bit Set

 

      InLabel flags: R-Readvertisement, N-Node SID, P-no PHP

                     E-Explicit null, V-Value, L-Local

 

      OutLabelFlags: E-Explicit null, I-Implicit null, N-Nomal, P-SR label prefer

The output shows TI-LFA backup next hop information.

 

 

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