Question

A service provider is deploying SR-MPLS across a multi-area IS-IS backbone. Two ABRs (PE-facing border routers R5 and R6) connect the access domain to the core. The design team wants ingress PEs to steer traffic toward either ABR interchangeably so that the loss of one ABR does not require a full recomputation of the SR label stack at the ingress node. Which segment routing mechanism should be configured on R5 and R6 to achieve this behavior?

Accepted Answer

Assign the same Anycast SID (identical prefix-SID index on a shared loopback prefix) to both R5 and R6

Answer

Assign unique Adjacency SIDs on every core-facing link of R5 and R6

Answer

Configure a Binding SID on the ingress PE pointing to R5 only, with R6 as an IGP backup

Answer

Enable the SR Global Block (SRGB) with different label ranges on R5 and R6