Configuration - Cisco NCS 5500 Series Configuration Manuals

Implementing Fast Reroute Loop-Free Alternate
FRR Remote LFA feature enables you to tunnel a packet around a failed link to a remote loop-free alternate
that is more than one hop away. In the figure above, the green arrow between A and D shows the tunnel that
is automatically created by the remote LFA feature to bypass looping.

Configuration

Perform the following tasks to configure FRR with LFA.
Configure FRR with local LFA
/* Configure FRR with local LFA using IS-IS */
Router# configure
Router(config)# router isis ring
Router(config)#
Router(config-isis)# net 49.0001.0000.0000.0007.00
Router(config-isis)# nsf cisco
Router(config-isis)# address-family ipv4 unicast
Router(config-isis-af)# metric-style wide
Router(config-isis-af)# mpls traffic-eng level-1-2
Router(config-isis-af)# mpls traffic-eng router-id 10.7.7.7
Router(config-isis-af)# exit
Router(config-isis)# interface Loopback 0
Router(config-isis-if)# point-to-point
Router(config-isis-if)# address-family ipv4 unicast
Router(config-isis-if)# exit
Router(config-isis)# interface TenGigabitEthernet 0/0/0/4
Router(config-isis-if)# point-to-point
Router(config-isis-if)# address-family ipv4 unicast
Router(config-isis-af)# fast-reroute per-prefix
Router(config-isis-af)# commit
/* Configure FRR with local LFA using OSPF*/
Router# configure
Router(config)# router ospf 50
Router(config-ospf)# router-id 10.1.1.1
Router(config-ospf)# address-family ipv4 unicast
Router(config-ospf-af)# area 0
Router(config-ospf-af)# mpls traffic-eng
Router(config-ospf-af)# interface Loopback 0
Router(config-ospf-af)# exit
Router(config-ospf)# interface HundredGigE0/2/0/0
Router(config-ospf-if)# fast-reroute per-prefix
Router(config-ospf-if)# exit
Router(config-ospf)# exit
Router(config)# mpls traffic-eng router-id Loopback 0
Configure remote FRR with remote LFA.
/* Configure FRR with remote LFA using IS-IS */
Router# configure
Router(config)# router isis ring
Router(config)#
Router(config-isis)# net 49.0001.0000.0000.0007.00
Router(config-isis)# nsf cisco
Router(config-isis)# address-family ipv4 unicast
Router(config-isis-af)# metric-style wide
Router(config-isis-af)# mpls traffic-eng level-1-2
is-type level-1
is-type level-1
Routing Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.3.x
Configuration
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