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| Title | Size | Download |
|---|---|---|
| 14-Static SR over MPLS configuration | 138.59 KB |
Contents
Configuring static SR over MPLS··
Static SR over MPLS configuration task list
Binding a static SRLSP to an MPLS TE tunnel interface
Displaying and maintaining static SRLSP
Static SRLSP configuration examples
Configuring static SR over MPLS
Overview
About SR and SRLSP
Segment Routing (SR) is a source routing technology. The source node selects a path for the packets, and then encodes the path as a list of segments in the packets. Each segment is identified by the segment identifier (SID). The SR nodes forward the arriving packets based on the SIDs in the packets. Only the source node needs to maintain the path status.
There are the following types of segments:
· 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.
SR can operate with MPLS. In an MPLS network, SR uses MPLS labels as SIDs to forward packets on an LSP. Such an LSP is referred to as a segment routing label switched path (SRLSP).
SRLSPs are special CRLSPs established based on SR. An MPLS TE tunnel can contain one or multiple SRLSPs. The source node (ingress node of an MPLS TE tunnel) forwards packets that are routed to the MPLS TE tunnel interface through the SRLSPs.
How static SR over MPLS works
Static SR over MPLS provides the following methods for establishing static SRLSPs:
· Prefix method—Each node on the SRLSP has the label information for other nodes. The label information is prefix-specific and manually configured. It includes the incoming label, outgoing label, and next hop. The label stack on the ingress node specifies all the other nodes that the forwarding path traverses.
· Adjacency method—Each node on the SRLSP has the label information for its adjacencies. The label information is manually configured and includes the incoming label and next hop. The label stack on the ingress node specifies all the links that the forwarding path traverses.
|
|
NOTE: The device supports only the adjacency method for static SRLSP establishment. |
Figure 1 shows how a static SRLSP forwards a packet.
1. Ingress node Device A adds a label stack to the packet and then forwards it to Device B.
The label stack is an ordered list of adjacency SIDs of the nodes that the SRLSP traverses: 201, 202, and 203.
2. When Device B receives the packet, it removes the top label of the label stack (label 201) and then forwards the packet to the next node Device C.
3. When Device C receives the packet, it removes the top label of the label stack (label 202) and then forwards the packet to the next node Device D.
4. When Device D receives the packet, it removes the last label (label 203) of the packet and then forwards the packet (an IP packet) to Device E (the egress node).
5. When egress node Device E receives the packet, it forwards the packet to the destination IP address.
Figure 1 How a static SRLSP forwards a packet (adjacency method)
Protocols and standards
· draft-ietf-spring-segment-routing-mpls-00
· draft-ietf-spring-segment-routing-02
Static SR over MPLS configuration task list
To configure static SR over MPLS, perform the following tasks:
1. Enable MPLS TE on all nodes and enable MPLS on all interfaces that will participate in MPLS TE forwarding.
2. Configure adjacency information on all nodes that the SRLSP might traverse.
3. Create a static SRLSP on the ingress node of the MPLS TE tunnel.
4. Create a tunnel interface on the ingress node of the MPLS TE tunnel, and specify the tunnel destination address.
5. On the ingress node of the MPLS TE tunnel, bind the created static SRLSP to the MPLS TE tunnel interface.
6. On the ingress node of the MPLS TE tunnel, configure static routing or PBR to direct traffic to the MPLS TE tunnel.
For information about configuring MPLS TE, see "Configuring MPLS TE." For information about configuring MPLS, see "Configuring basic MPLS."
The following table lists the SRLSP-specific tasks:
|
Tasks at a glance |
Remarks |
|
(Required.) Configuring an adjacency path |
Perform this task on all nodes that a static SRLSP might traverse. |
|
(Required.) Configuring a static SRLSP |
Perform this task only on the ingress node of a static SRLSP. |
|
(Required.) Binding a static SRLSP to an MPLS TE tunnel interface |
Perform this task only on the ingress node of a static SRLSP. |
Prerequisites
Before you configure static SR over MPLS, perform the following tasks:
· Determine the ingress node, transit nodes, and egress node of a static LSP.
· Determine the incoming label of each transit node's adjacency to a neighbor. On a device, a static SRLSP, a static LSP, and a static CRLSP cannot use the same incoming label.
· Enable MPLS on interfaces that will participate in MPLS forwarding. For information about enabling MPLS, see "Configuring basic MPLS."
Configuring an adjacency path
Perform this task on all nodes that a static SRLSP might traverse.
Multiple static SRLSPs can share an adjacency path.
To configure an adjacency path:
|
Step |
Command |
Remarks |
|
1. Enter system view. |
system-view |
N/A |
|
2. Configure an adjacency path. |
static-sr-mpls adjacency adjacency-path-name in-label label-value { nexthop ip-address | outgoing-interface interface-type interface-number } |
By default, no adjacency paths exist. Do not specify a local public IP address as the next hop address when configuring an adjacency path. |
Configuring a static SRLSP
Perform this task only on the ingress node of a static SRLSP.
To use a static SRLSP to forward MPLS TE traffic, you must first perform the following operations:
1. Create an MPLS TE tunnel interface on the ingress node.
2. Bind the static SRLSP to the tunnel interface.
For information about configuring MPLS TE, see "Configuring MPLS TE."
To configure a static SRLSP:
|
Step |
Command |
Remarks |
|
1. Enter system view. |
system-view |
N/A |
|
2. Configure a static SRLSP. |
static-sr-mpls lsp lsp-name out-label out-label-value&<1-13> |
By default, no static SRLSPs exist. |
Binding a static SRLSP to an MPLS TE tunnel interface
Perform this task only on the ingress node of a static SRLSP.
To bind a static SRLSP to an MPLS TE tunnel interface:
|
Step |
Command |
Remarks |
|
1. Enter system view. |
system-view |
N/A |
|
2. Enter MPLS TE tunnel interface view. |
interface tunnel tunnel-number [ mode mpls-te ] |
N/A |
|
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-lsp lsp-name |
By default, an MPLS TE tunnel does not use a static SRLSP. |
Displaying and maintaining static SRLSP
Execute display commands in any view.
|
Task |
Command |
|
Display static SRLSP and adjacency path information. |
display mpls static-sr-lsp [ lsp lsp-name | adjacency adjacency-path-name ] |
Static SRLSP configuration examples
Network requirements
As shown in Figure 2, Router A, Router B, Router C, Router D, Router E, and Router F 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 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 E to Router F to transmit data between the IP networks. The static SRLSP traverses three segments: Router E-Router B, Router B-Router C, and Router C-Router F.
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 |
|
|
GE1/1/1 |
10.1.1.1/24 |
|
GE1/1/1 |
10.1.1.2/24 |
|
|
GE1/1/2 |
100.1.1.1/24 |
|
GE1/1/2 |
20.1.1.1/24 |
|
Router C |
Loop0 |
3.3.3.9/32 |
|
GE1/1/3 |
40.1.1.1/24 |
|
|
GE1/1/1 |
30.1.1.1/24 |
Router D |
Loop0 |
4.4.4.9/32 |
|
|
GE1/1/2 |
20.1.1.2/24 |
|
GE1/1/1 |
100.1.2.1/24 |
|
|
GE1/1/3 |
50.1.1.1/24 |
|
GE1/1/2 |
30.1.1.2/24 |
|
Router E |
Loop0 |
5.5.5.9/32 |
Router F |
Loop0 |
6.6.6.9/32 |
|
|
GE1/1/1 |
200.1.1.1/24 |
|
GE1/1/1 |
200.1.2.1/24 |
|
|
GE1/1/2 |
40.1.1.2/24 |
|
GE1/1/2 |
50.1.1.2/24 |
Configuration procedure
1. Configure IP addresses and masks for interfaces. (Details not shown.)
2. Configure IS-IS to advertise interface addresses, including the loopback interface address. (Details not shown.)
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. (Details not shown.)
4. 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 gigabitethernet 1/1/2
[RouterA-GigabitEthernet1/1/2] mpls enable
[RouterA-GigabitEthernet1/1/2] quit
# Configure Router B.
<RouterB> system-view
[RouterB] mpls lsr-id 2.2.2.9
[RouterB] mpls te
[RouterB-te] quit
[RouterB] interface gigabitethernet 1/1/1
[RouterB-GigabitEthernet1/1/1] mpls enable
[RouterB-GigabitEthernet1/1/1] quit
[RouterB] interface gigabitethernet 1/1/2
[RouterB-GigabitEthernet1/1/2] mpls enable
[RouterB-GigabitEthernet1/1/2] quit
[RouterB] interface gigabitethernet 1/1/3
[RouterB-GigabitEthernet1/1/3] mpls enable
[RouterB-GigabitEthernet1/1/3] quit
# Configure Router C.
<RouterC> system-view
[RouterC] mpls lsr-id 3.3.3.9
[RouterC] mpls te
[RouterC-te] quit
[RouterC] interface gigabitethernet 1/1/1
[RouterC-GigabitEthernet1/1/1] mpls enable
[RouterC-GigabitEthernet1/1/1] quit
[RouterC] interface gigabitethernet 1/1/2
[RouterC-GigabitEthernet1/1/2] mpls enable
[RouterC-GigabitEthernet1/1/2] quit
[RouterC] interface gigabitethernet 1/1/3
[RouterC-GigabitEthernet1/1/3] mpls enable
[RouterC-GigabitEthernet1/1/3] quit
# Configure Router D.
<RouterD> system-view
[RouterD] mpls lsr-id 4.4.4.9
[RouterD] mpls te
[RouterD-te] quit
[RouterD] interface gigabitethernet 1/1/2
[RouterD-GigabitEthernet1/1/2] mpls enable
[RouterD-GigabitEthernet1/1/2] quit
# Configure Router E.
<RouterE> system-view
[RouterE] mpls lsr-id 5.5.5.9
[RouterE] mpls te
[RouterE-te] quit
[RouterE] interface gigabitethernet 1/1/2
[RouterE-GigabitEthernet1/1/2] mpls enable
[RouterE-GigabitEthernet1/1/2] quit
# Configure Router F.
<RouterF> system-view
[RouterF] mpls lsr-id 6.6.6.9
[RouterF] mpls te
[RouterF-te] quit
[RouterF] interface gigabitethernet 1/1/2
[RouterF-GigabitEthernet1/1/2] mpls enable
[RouterF-GigabitEthernet1/1/2] quit
5. Configure adjacency path labels on each node:
# On Router A, bind label 16 to next hop 10.1.1.2.
[RouterA] static-sr-mpls adjacency adjacency-1 in-label 16 nexthop 10.1.1.2
# On Router B, bind labels 20, 21, and 22 to next hops 10.1.1.1, 20.1.1.2, and 40.1.1.2, respectively.
[RouterB] static-sr-mpls adjacency adjacency-1 in-label 20 nexthop 10.1.1.1
[RouterB] static-sr-mpls adjacency adjacency-2 in-label 21 nexthop 20.1.1.2
[RouterB] static-sr-mpls adjacency adjacency-3 in-label 22 nexthop 40.1.1.2
# On Router C, bind labels 30, 31, and 32 to next hops 30.1.1.2, 50.1.1.2, and 20.1.1.1, respectively.
[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
[RouterC] static-sr-mpls adjacency adjacency-3 in-label 32 nexthop 20.1.1.1
# On Router D, bind label 40 to next hop 30.1.1.1.
[RouterD] static-sr-mpls adjacency adjacency-1 in-label 40 nexthop 30.1.1.1
# On Router E, bind label 50 to next hop 40.1.1.1.
[RouterE] static-sr-mpls adjacency adjacency-1 in-label 50 nexthop 40.1.1.1
# On Router F, bind label 60 to next hop 50.1.1.1.
[RouterF] static-sr-mpls adjacency adjacency-1 in-label 60 nexthop 50.1.1.1
6. Create static SRLSPs:
# Configure Router A as the ingress node of static SRLSP static-sr-lsp-1 and configure an outgoing label stack of [16, 21, 30].
[RouterA] static-sr-mpls lsp static-sr-lsp-1 out-label 16 21 30
# Configure Router E as the ingress node of static SRLSP static-sr-lsp-2 and configure an outgoing label stack of [50, 21, 31].
[RouterE] static-sr-mpls lsp static-sr-lsp-2 out-label 50 21 31
7. 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.
[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] quit
# On Router E, establish static MPLS TE tunnel 0 to Router F and specify the tunnel destination address as the LSR ID of Router F.
[RouterE] interface tunnel 0 mode mpls-te
[RouterE-Tunnel0] ip address 7.1.1.1 255.255.255.0
[RouterE-Tunnel0] destination 6.6.6.9
[RouterE-Tunnel0] mpls te signaling static
[RouterE-Tunnel0] quit
# Bind static SRLSP static-sr-lsp-1 to MPLS TE tunnel interface 0 on Router A.
[RouterA] interface tunnel 0
[RouterA-Tunnel0] mpls te static-sr-mpls static-sr-lsp-1
[RouterA-Tunnel0] quit
# Bind static SRLSP static-sr-lsp-2 to MPLS TE tunnel interface 0 on Router E.
[RouterE] interface tunnel 0
[RouterE-Tunnel0] mpls te static-sr-mpls static-sr-lsp-2
[RouterE-Tunnel0] quit
8. Configure static routes to direct traffic to the MPLS TE tunnels:
# Configure a static route on Router A to direct traffic destined for 100.1.2.0/24 to MPLS TE tunnel 0.
[RouterA] ip route-static 100.1.2.0 24 tunnel 0 preference 1
# Configure a static route on Router E to direct traffic destined for 200.1.2.0/24 to MPLS TE tunnel 0.
[RouterE] ip route-static 200.1.2.0 24 tunnel 0 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
Static SRLSP Name : static-sr-lsp-1/-
Signaling : Static Static CRLSP Name : -
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 : -
# Display the MPLS TE tunnel information on Router E.
[RouterE] 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 : 5.5.5.9 Egress LSR ID : 6.6.6.9
Static SRLSP Name : static-sr-lsp-2/-
Signaling : Static Static CRLSP Name : -
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 : -
# Display the static CRLSP information on Router A, Router B, and Router C.
[RouterA] display mpls lsp
FEC Proto In/Out Label Interface/Out NHLFE
1.1.1.1/1/1 StaticCR -/20 GE1/1/2
30
[RouterB] display mpls lsp
FEC Proto In/Out Label Interface/Out NHLFE
- StaticCR 20/- GE1/1/2
[RouterC] display mpls lsp
FEC Proto In/Out Label Interface/Out NHLFE
- StaticCR 30/- GE1/1/1
- StaticCR 40/- GE1/1/3
