Configure Remote Loop-Free Alternate Paths For Is-Is - Cisco NCS 6000 Series Configuration Manual

Configure Remote Loop-Free Alternate Paths for IS-IS

DETAILED STEPS
Command or Action
Step 1 configure
Step 2 router isis instance-id
Example:
RP/0/RP0/CPU0:router(config)# router isis isp
Step 3
interface type interface-path-id
Example:
RP/0/RP0/CPU0:router(config-isis)# interface
GigabitEthernet 0/1/0/3
Step 4
circuit-type { level-1 | level-1-2 | level-2-only }
Example:
RP/0/RP0/CPU0:router(config-isis-if)# circuit-type
level-1
Step 5
address-family ipv4 unicast
Example:
RP/0/RP0/CPU0:router(config-isis-if)#
address-family ipv4 unicast
Step 6
ipfrr lfa { level { 1 | 2 }}
Example:
RP/0/RP0/CPU0:router(config-isis-if-af)# ipfrr lfa
level 1
Step 7 ipfrr lfa exclude interface type interface-path-id
Example:
RP/0/RP0/CPU0:router(config-isis-if-af)#ipfrr lfa
exclude interface POS 0/1/0/4
Step 8 commit
Configure Remote Loop-Free Alternate Paths for IS-IS
IP Fast Re-Route (FRR) with Loop-Free Alternate (LFA) paths uses only the immediate next hops
(directly-connected neighbors) as backups to a destination. Though this works well in most topologies, it fails
in ring topologies, because the immediate next hop is likely to use the source router itself to forward traffic,
thereby creating loops.
Routing Configuration Guide for Cisco NCS 6000 Series Routers, IOS XR Release 6.4.x
238
Purpose
Enables IS-IS routing for the specified routing process, and
places the router in router configuration mode. In this
example, the IS-IS instance is called isp.
Enters interface configuration mode.
(Optional) Configures the type of adjacency.
Specifies the IPv4 address family, and enters router address
family configuration mode.
Specifies the IP fast reroute loop-free alternate computation
on link or node failures.
(Optional) Excludes an interface from the IP fast reroute
loop-free alternate computation.
Implementing IS-IS