SR-TE Configuration Prerequisites

To configure SR-TE, the user must first configure the prerequisite parameters.

First, configure the label space partition for the Segment Routing Global Block (SRGB) for all participating routers in the segment routing domain by using the mpls-labels>sr-labels command.

Example:

configure>router>mpls-labels
    sr-labels start 200000 end 200400
exit

Enable segment routing, traffic engineering, and advertisement of router capability in all participating IGP instances in all participating routers by using the traffic-engineering, advertise-router-capability, and segment-routing commands.

Example:

ospf 0
    traffic-engineering
    advertise-router-capability area
    loopfree-alternates remote-lfa
    area 0.0.0.202
        stub
            no summaries
        exit
        interface "system"
            node-sid index 194
            no shutdown
        exit
        interface "toSim199"
            interface-type point-to-point
            no shutdown
        exit
        interface "toSim213"
            interface-type point-to-point
            no shutdown
        exit
        interface "toSim219"
            interface-type point-to-point
            metric 2000
            no shutdown
        exit
    exit
    segment-routing
        prefix-sid-range global
        entropy-label {force-disable | enable} 
        no shutdown
    exit
    no shutdown
exit

Configure a segment routing tunnel MTU for the IGP instance, if required, by using the tunnel-mtu command.

Example:

prefix-sid-range global
tunnel-mtu 1500
no shutdown

Assign a node SID to each loopback interface that a router would use as the destination of a segment routing tunnel by using the node-sid command.

Example:

ospf 0
    area 0.0.0.202
        interface "system"
            node-sid index 194
            no shutdown
        exit