Contents

Introduction· 1

Prerequisites· 1

Example: Configuring SR-MPLS over LDP for network connections· 1

Network configuration· 1

Analysis· 2

Applicable hardware and software versions· 2

Procedures· 4

Configuring Device A· 4

Configuring Device B· 5

Configuring Device C· 6

Configuring Device D·· 7

Configuring Device E· 7

Verifying the configuration· 8

Configuration files· 9

Device A· 9

Device B· 10

Device C· 11

Device D·· 12

Device E· 13

 

Introduction

This document provides SR-MPLS configuration examples.

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 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.

Prerequisites

The configuration examples were created and verified in a lab environment, and all the devices were started with the factory default configuration. When you are working on a live network, make sure you understand the potential impact of every command on your network.

The following information is provided based on the assumption that you have basic knowledge of SR-MPLS.

Example: Configuring SR-MPLS over LDP for network connections

Network configuration

As shown in Figure 1, the SR-MPLS network is segmented by an LDP network. To enable communication between the two SR-MPLS network segments across the LDP network, establish label connectivity between the SR-MPLS and LDP networks. When Device A forwards traffic to Device E through the related SRLSP, you must configure both Device B and Device D to ensure that the two SR-MPLS network segments can communicate across the LDP network.

Figure 1 Network diagram

 

 

Analysis

·     Configure Device A, Device B, Device C, Device D, and Device E to run IS-IS.

·      Configure Device B, Device C, and Device D to run LDP.

·     Configure Device A, Device B, Device D, and Device E to run SR-MPLS.

Applicable hardware and software versions

 

Procedures

Configuring Device A

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

# Configure IS-IS to achieve network level connectivity and set the IS-IS cost style to wide.

<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 vlan-interface 100

[DeviceA-Vlan-interface100] isis enable 1

[DeviceA-Vlan-interface100] quit

[DeviceA] interface loopback 1

[DeviceA-LoopBack1] isis enable 1

[DeviceA-LoopBack1] quit

# Configure an MPLS LSR ID.

[DeviceA] mpls lsr-id 1.1.1.1

# Enable SR-MPLS for IS-IS.

[DeviceA] isis 1

[DeviceA-isis-1] address-family ipv4

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

[DeviceA-isis-1-ipv4] quit

# Configure an MPLS SRGB.

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

[DeviceA-isis-1] quit

# Configure an IS-IS prefix SID.

[DeviceA] interface loopback 1

[DeviceA-LoopBack1] isis prefix-sid index 10

[DeviceA-LoopBack1] quit

Configuring Device B

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

# Configure IS-IS to achieve network level connectivity and set the IS-IS cost style to wide.

<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 vlan-interface 100

[DeviceB-Vlan-interface100] isis enable 1

[DeviceB-Vlan-interface100] quit

[DeviceB] interface vlan-interface 200

[DeviceB-Vlan-interface200] isis enable 1

[DeviceB-Vlan-interface200] quit

[DeviceB] interface loopback 1

[DeviceB-LoopBack1] isis enable 1

[DeviceB-LoopBack1] quit

# Configure an MPLS LSR ID.

[DeviceB] mpls lsr-id 2.2.2.2

# Configure LDP.

[DeviceB] mpls ldp

[DeviceB-ldp] quit

[DeviceB] interface vlan-interface 200

[DeviceB-Vlan-interface200] mpls enable

[DeviceB-Vlan-interface200] mpls ldp enable

[DeviceB-Vlan-interface200] quit

# Enable SR-MPLS for IS-IS.

[DeviceB] isis 1

[DeviceB-isis-1] address-family ipv4

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

[DeviceB-isis-1-ipv4] quit

# Configure an MPLS SRGB.

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

[DeviceB-isis-1] quit

# Configure an IS-IS prefix SID.

[DeviceB] interface loopback 1

[DeviceB-LoopBack1] isis prefix-sid index 20

[DeviceB-LoopBack1] quit

Configuring Device C

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

# Configure IS-IS to achieve network level connectivity and set the IS-IS cost style to wide.

<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 vlan-interface 100

[DeviceC-Vlan-interface100] isis enable 1

[DeviceC-Vlan-interface100] quit

[DeviceC] interface vlan-interface 200

[DeviceC-Vlan-interface200] isis enable 1

[DeviceC-Vlan-interface200] quit

[DeviceC] interface loopback 1

[DeviceC-LoopBack1] isis enable 1

[DeviceC-LoopBack1] quit

# Configure an MPLS LSR ID.

[DeviceC] mpls lsr-id 3.3.3.3

# Configure LDP.

[DeviceC] mpls ldp

[DeviceC-ldp] quit

[DeviceC] interface vlan-interface 100

[DeviceC-Vlan-interface100] mpls enable

[DeviceC-Vlan-interface100] mpls ldp enable

[DeviceC-Vlan-interface100] quit

[DeviceC] interface vlan-interface 200

[DeviceC-Vlan-interface200] mpls enable

[DeviceC-Vlan-interface200] mpls ldp enable

[DeviceC-Vlan-interface200] quit

Configuring Device D

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

# Configure IS-IS to achieve network level connectivity and set the IS-IS cost style to wide.

<DeviceD> system-view

[DeviceD] isis 1

[DeviceD-isis-1] network-entity 00.0000.0000.0004.00

[DeviceD-isis-1] cost-style wide

[DeviceD-isis-1] quit

[DeviceD] interface vlan-interface 100

[DeviceD-Vlan-interface100] isis enable 1

[DeviceD-Vlan-interface100] quit

[DeviceD] interface vlan-interface 200

[DeviceD-Vlan-interface200] isis enable 1

[DeviceD-Vlan-interface200] quit

[DeviceD] interface loopback 1

[DeviceD-LoopBack1] isis enable 1

[DeviceD-LoopBack1] quit

# Configure an MPLS LSR ID.

[DeviceD] mpls lsr-id 4.4.4.4

# Configure LDP.

[DeviceD] mpls ldp

[DeviceD-ldp] quit

[DeviceD] interface vlan-interface 100

[DeviceD-Vlan-interface1001] mpls enable

[DeviceD-Vlan-interface100] mpls ldp enable

[DeviceD-Vlan-interface100] quit

# Enable SR-MPLS for IS-IS.

[DeviceD] isis 1

[DeviceD-isis-1] address-family ipv4

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

[DeviceD-isis-1-ipv4] quit

# Configure an MPLS SRGB.

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

[DeviceD-isis-1] quit

# Configure an IS-IS prefix SID.

[DeviceD] interface loopback 1

[DeviceD-LoopBack1] isis prefix-sid index 40

[DeviceD-LoopBack1] quit

Configuring Device E

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

# Configure IS-IS to achieve network level connectivity and set the IS-IS cost style to wide.

<DeviceE> system-view

[DeviceE] isis 1

[DeviceE-isis-1] network-entity 00.0000.0000.0005.00

[DeviceE-isis-1] cost-style wide

[DeviceE-isis-1] quit

[DeviceE] interface vlan-interface 200

[DeviceE-Vlan-interface200] isis enable 1

[DeviceE-Vlan-interface200] quit

[DeviceE] interface loopback 1

[DeviceE-LoopBack1] isis enable 1

[DeviceE-LoopBack1] quit

# Configure an MPLS LSR ID.

[DeviceE] mpls lsr-id 5.5.5.5

# Enable SR-MPLS for IS-IS.

[DeviceE] isis 1

[DeviceE-isis-1] address-family ipv4

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

[DeviceE-isis-1-ipv4] quit

# Configure an MPLS SRGB.

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

[DeviceE-isis-1] quit

# Configure an IS-IS prefix SID.

[DeviceE] interface loopback 1

[DeviceE-LoopBack1] isis prefix-sid index 50

[DeviceE-LoopBack1] quit

Verifying the configuration

# Display LDP LSP information on Device B.

[DeviceB] 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         24116/-

                   -/24117(L)

2.2.2.2/32         3/-

                   -/24120(L)

3.3.3.3/32         -/3                 11.0.0.2        Vlan200

                   24121/3             11.0.0.2        Vlan200

4.4.4.4/32         -/24119             11.0.0.2        Vlan200

                   24118/24119         11.0.0.2        Vlan200

5.5.5.5/32         -/24118             11.0.0.2        Vlan200

                   24117/24118         11.0.0.2        Vlan200

# Display IS-IS SRLSP information on Device B.

[DeviceB] display mpls lsp protocol isis

FEC                         Proto       In/Out Label    Interface/Out NHLFE

1.1.1.1/32                  ISIS        17010/3         Vlan100

1.1.1.1/32                  ISIS        -/3             Vlan100

2.2.2.2/32                  ISIS        17020/-         -

4.4.4.4/32                  ISIS        17040/24119     Vlan200

4.4.4.4/32                  ISIS        -/24119         Vlan200

5.5.5.5/32                  ISIS        17050/24118     Vlan200

5.5.5.5/32                  ISIS        -/24118         Vlan200

The output shows that the IS-IS SRLSP entries for Device D and Device E are using LDP outgoing labels.

Configuration files

Device A

#

isis 1

 cost-style wide

 segment-routing global-block 16000 16999

 network-entity 00.0000.0000.0001.00

 #

 address-family ipv4 unicast

  segment-routing mpls

#

 mpls lsr-id 1.1.1.1

#

vlan 1

#

vlan 100

#

interface LoopBack1

 ip address 1.1.1.1 255.255.255.255

 isis enable 1

 isis prefix-sid index 10

#

interface Vlan-interface100

 ip address 10.0.0.1 255.255.255.0

 isis enable 1

#

interface GigabitEthernet1/0/1

 port link-mode bridge

 port access vlan 100

 combo enable fiber

#

Device B

#

isis 1

 cost-style wide

 segment-routing global-block 17000 17999

 network-entity 00.0000.0000.0002.00

 #

 address-family ipv4 unicast

  segment-routing mpls

#

 mpls lsr-id 2.2.2.2

#

vlan 1

#

vlan 100

#

vlan 200

#

mpls ldp

#

interface LoopBack1

 ip address 2.2.2.2 255.255.255.255

 isis enable 1

 isis prefix-sid index 20

#

interface Vlan-interface100

 ip address 10.0.0.2 255.255.255.0

 isis enable 1

#

interface Vlan-interface200

 ip address 11.0.0.1 255.255.255.0

 isis enable 1

 mpls enable

 mpls ldp enable

#

interface GigabitEthernet1/0/1

 port link-mode bridge

 port access vlan 100

 combo enable fiber

#

interface GigabitEthernet1/0/2

 port link-mode bridge

 port access vlan 200

 combo enable fiber

#

Device C

#

isis 1

 cost-style wide

 network-entity 00.0000.0000.0003.00

#

 mpls lsr-id 3.3.3.3

#

vlan 1

#

vlan 100

#

vlan 200

#

mpls ldp

#

interface LoopBack1

 ip address 3.3.3.3 255.255.255.255

 isis enable 1

#

interface Vlan-interface100

 ip address 12.0.0.1 255.255.255.0

 isis enable 1

 mpls enable

 mpls ldp enable

#

interface Vlan-interface200

 ip address 11.0.0.2 255.255.255.0

 isis enable 1

 mpls enable

 mpls ldp enable

#

interface GigabitEthernet1/0/1

 port link-mode bridge

 port access vlan 200

 combo enable fiber

#

interface GigabitEthernet1/0/2

 port link-mode bridge

 port access vlan 100

 combo enable fiber

#

Device D

#

isis 1

 cost-style wide

 segment-routing global-block 18000 18999

 network-entity 00.0000.0000.0004.00

 #

 address-family ipv4 unicast

  segment-routing mpls

#

 mpls lsr-id 4.4.4.4

#

vlan 1

#

vlan 100

#

vlan 200

#

mpls ldp

#

interface LoopBack1

 ip address 4.4.4.4 255.255.255.255

 isis enable 1

 isis prefix-sid index 40

#

interface Vlan-interface100

 ip address 12.0.0.2 255.255.255.0

 isis enable 1

 mpls enable

 mpls ldp enable

#

interface Vlan-interface200

 ip address 13.0.0.1 255.255.255.0

 isis enable 1

#

interface GigabitEthernet1/0/1

 port link-mode bridge

 port access vlan 100

 combo enable fiber

#

interface GigabitEthernet1/0/2

 port link-mode bridge

 port access vlan 200

 combo enable fiber

#

Device E

#

isis 1

 cost-style wide

 segment-routing global-block 19000 19999

 network-entity 00.0000.0000.0005.00

 #

 address-family ipv4 unicast

  segment-routing mpls

#

 mpls lsr-id 5.5.5.5

#

vlan 1

#

vlan 200

#

interface LoopBack1

 ip address 5.5.5.5 255.255.255.255

 isis enable 1

 isis prefix-sid index 50

#

interface Vlan-interface200

 ip address 13.0.0.2 255.255.255.0

 isis enable 1

#

interface GigabitEthernet1/0/1

 port link-mode bridge

 port access vlan 200

 combo enable fiber

#