R0106-HP MSR Router Series Layer 3 - IP Routing Configuration Guide(V7)

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• Configure IS-IS FRR so that when Link A fails, traffic can be switched to Link B immediately.
Figure 49 Network diagram
Configuration procedure
1. Configure IP addresses and subnet masks for interfaces on the routers. (Details not shown.)
2. Configure IS-IS on the routers to make sure Router A, Router D, and Router S can communicate with
each other at the network layer. (Details not shown.)
3. Configure IS-IS FRR:
Enable IS-IS FRR to automatically calculate a backup next hop, or designate a backup next hop by
using a routing policy.
{ (Method 1.) Enable IS-IS FRR to automatically calculate a backup next hop:
# Configure Router S.
<RouterS> system-view
[RouterS] isis 1
[RouterS-isis-1] address-family ipv4
[RouterS-isis-1-ipv4] fast-reroute auto
[RouterS-isis-1-ipv4] quit
[RouterS-isis-1] quit
# Configure Router D.
<RouterD> system-view
[RouterD] isis 1
[RouterD-isis-1] address-family ipv4
[RouterS-isis-1-ipv4] fast-reroute auto
[RouterD-isis-1-ipv4] quit
[RouterD-isis-1] quit
{ (Method 2.) Enable IS-IS FRR to designate a backup next hop by using a routing policy:
# Configure Router S.
<RouterS> system-view
[RouterS] ip prefix-list abc index 10 permit 4.4.4.4 32
[RouterS] route-policy frr permit node 10
[RouterS-route-policy-frr-10] if-match ip address prefix-list abc
[RouterS-route-policy-frr-10] apply fast-reroute backup-interface
gigabitethernet 2/1/1 backup-nexthop 12.12.12.2
[RouterS-route-policy-frr-10] quit
[RouterS] isis 1
[RouterS-isis-1] address-family ipv4
[RouterS-isis-1-ipv4] fast-reroute route-policy frr
[RouterS-isis-1-ipv4] quit