Specifications

Implementing IS-IS on Cisco IOS XR Software
Information About Implementing IS-IS on Cisco IOS XR Software
RC-171
Cisco IOS XR Routing Configuration Guide
Interface Configuration Mode
The following example shows how to enter interface configuration mode:
RP/0/RP0/CPU0:router(config)# router isis isp
RP/0/RP0/CPU0:router(config-isis)# interface POS0/3/0/0
RP/0/RP0/CPU0:router(config-isis-if)#
Interface Address Family Configuration Mode
The following example shows how to enter interface address family configuration mode:
RP/0/RP0/CPU0:router(config)# router isis isp
RP/0/RP0/CPU0:router(config-isis)# interface POS0/3/0/0
RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast
RP/0/RP0/CPU0:router(config-isis-if-af)#
IS-IS Interfaces
IS-IS interfaces can be configured as one of the following types:
• active—advertises connected prefixes and forms adjacencies. This is the default for interfaces.
• passive—advertises connected prefixes but does not form adjacencies. The passive command is
used to configure interfaces as passive. Passive interfaces should be used sparingly for important
prefixes such as loopback addresses that need to be injected into the IS-IS domain. If many
connected prefixes need to be advertised then the redistribution of connected routes with the
appropriate policy should be used instead.
• suppressed—does not advertise connected prefixes but forms adjacencies. The suppress command
is used to configure interfaces as suppressed.
• shutdown—does not advertise connected prefixes and does not form adjacencies. The shutdown
command is used to disable interfaces without removing the IS-IS configuration.
Multitopology Configuration
Cisco IOS XR software supports multitopology for IPv6 IS-IS unless single topology is explicitly
configured in IPv6 address-family configuration mode.
Note IS-IS supports IP routing and not Open Systems Interconnection (OSI) Connectionless Network Service
(CLNS) routing.
IPv6 Routing and Configuring IPv6 Addressing
By default, IPv6 routing is disabled in the Cisco IOS XR software. To enable IPv6 routing, you must
assign IPv6 addresses to individual interfaces in the router using the ipv6 enable or ipv6 address
command. See the Network Stack IPv4 and IPv6 Commands on Cisco IOS XR Software module of
Cisco IOS XR IP Addresses and Services Command Reference.