Specifications
RC-167
Cisco IOS XR Routing Configuration Guide
Implementing IS-IS on Cisco IOS XR Software
Integrated Intermediate System-to-Intermediate System (IS-IS), Internet Protocol Version 4 (IPv4), is a 
standards-based Interior Gateway Protocol (IGP).
Cisco IOS XR implements the IP routing capabilities described in International Organization for 
Standardization (ISO)/International Engineering Consortium (IEC) 10589 and RFC 1995, and adds the 
standard extensions for single topology and multitopology IS-IS for IP Version 6 (IPv6). 
This module describes the new and revised tasks you need to implement IS-IS (IPv4 and IPv6) on your 
Cisco IOS XR network.
Note For more information about IS-IS on Cisco IOS XR software and complete descriptions of the IS-IS 
commands listed in this module, you can refer to the “Related Documents” section of this module. To 
locate documentation for other commands that might appear while of executing a configuration task, 
search online in the Cisco IOS XR software master command index.
Feature History for Implementing IS-IS on Cisco IOS XR Software 
Release Modification
Release 2.0  This feature was introduced on the Cisco CRS-1.
Release 3.0 No modification.
Release 3.2 Support was added for the Cisco XR 12000 Series Router. The ability to 
configure a broadcast medium connecting two networking devices as a 
point-to-point link was added.
Release 3.3.0 LDP IGP synchronization support was added for IPv4 unicast address 
families. See the “MPLS Label Distribution Protocol IGP Synchronization” 
section on page RC-177 and “Configuring MPLS LDP IS-IS 
Synchronization” section on page RC-208 for more information. 
The ispf startup-delay command was removed from the “Setting SPF 
Interval for a Single-Topology IPv4 and IPv6 Configuration” section on 
page RC-203.










