SR-TE configuration prerequisites

About this task

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

Procedure

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
```
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
            — 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
```