Cisco NCS 6000 Series User Manual

DETAILED STEPS
PurposeCommand or Action
configure
Step 1
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.
router isis instance-id
Example:
RP/0/RP0/CPU0:router(config)# router isis isp
Step 2
Enters interface configuration mode.
interface type interface-path-id
Example:
Step 3
RP/0/RP0/CPU0:router(config-isis)# interface
GigabitEthernet 0/1/0/3
(Optional) Configures the type of adjacency.circuit-type { level-1 | level-1-2 | level-2-only }
Example:
Step 4
RP/0/RP0/CPU0:router(config-isis-if)# circuit-type
level-1
Specifies the IPv4 address family, and enters router address
family configuration mode.
address-family ipv4 unicast
Example:
Step 5
RP/0/RP0/CPU0:router(config-isis-if)#
address-family ipv4 unicast
Specifies the IP fast reroute loop-free alternate computation
on link or node failures.
ipfrr lfa { level { 1 | 2 }}
Example:
Step 6
RP/0/RP0/CPU0:router(config-isis-if-af)# ipfrr lfa
level 1
(Optional) Excludes an interface from the IP fast reroute
loop-free alternate computation.
ipfrr lfa exclude interface type interface-path-id
Example:
Step 7
RP/0/RP0/CPU0:router(config-isis-if-af)#ipfrr lfa
exclude interface POS 0/1/0/4
commit
Step 8
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
Implementing IS-IS
Configure Remote Loop-Free Alternate Paths for IS-IS

Cisco NCS 6000 Series Specifications

General

Brand	Cisco
Model	NCS 6000 Series
Category	Network Router
Language	English