Configuration

We will now configure the interfaces to belong to the same SRLG and instruct TI-LFA to provide SRLG protection in the next section.

The following configuration sets up an SRLG group named SRLG-100 on the Gi0/0/0/0 and Gi0/0/0/1 interfaces on router P2, as shown in Figure 11.1, recognizing them as sharing the same risk:

P2

srlg
name SRLG-100 value 100
!
interface GigabitEthernet0/0/0/0
  name SRLG-100
!
interface GigabitEthernet0/0/0/3
  name SRLG-100
!
router isis IGP
address-family ipv4 unicast
  fast-reroute per-prefix tiebreaker srlg-disjoint index 100

Although the SRLG group name is locally significant to router P2, the value of 100 can later hold significance network-wide, as further explored in the Global Weighted SRLG chapter.

SRLG protection is then requested as part of the tiebreaker configuration under the IS-IS routing protocol, with an index value of 100, as shown next.

SRLG-100 and the tiebreaker index value...