Specifications

Implementing IS-IS on Cisco IOS XR Software
How to Implement IS-IS on Cisco IOS XR Software
RC-179
Cisco IOS XR Routing Configuration Guide
MPLS TE Interarea Tunnels
MPLS TE interarea tunnels allow you to establish MPLS TE tunnels that span multiple IGP areas (Open
Shorted Path First [OSPF]) and levels (IS-IS), removing the restriction that required that both the tunnel
headend and tailend routers be in the same area. The IGP can be either IS-IS or OSPF. See the
“Configuring MPLS Traffic Engineering for IS-IS” section on page RC-197 for information on
configuring MPLS TE for IS-IS.
For details on configuring MPLS TE interarea tunnels, see Cisco IOS XR Multiprotocol Label Switching
Configuration Guide.
IP Fast Reroute
The IP Fast Reroute (IPFRR) loop-free alternate (LFA) computation provides protection against link
failure. Locally computed repair paths are used to prevent packet loss caused by loops that occur during
network reconvergence after a failure. See IETF draft-ietf-rtgwg-ipfrr-framework-06.txt and
draft-ietf-rtgwg-lf-conv-frmwk-00.txt for detailed information on IPFRR LFA.
Note IPFRR is supported on the Cisco CRS-1 router.
IPFRR LFA is different from Multiprotocol Label Switching (MPLS) as it is applicable to networks
using conventional IP routing and forwarding. See Multiprotocol Label Switching Configuration Guide
for information on configuring MPLS IPFRR.
How to Implement IS-IS on Cisco IOS XR Software
This section contains the following procedures:
• Enabling IS-IS and Configuring Level 1 or Level 2 Routing, page RC-180 (required)
• Configuring Single Topology for IS-IS, page RC-182 (optional)
• Configuring Multitopology for IS-IS, page RC-186 (optional)
• Controlling LSP Flooding for IS-IS, page RC-187 (optional)
• Configuring Nonstop Forwarding for IS-IS, page RC-191 (optional)
• Configuring Authentication for IS-IS, page RC-193 (optional)
• Configuring Keychains for IS-IS, page RC-195 (optional)
• Configuring MPLS Traffic Engineering for IS-IS, page RC-197 (optional)
• Tuning Adjacencies for IS-IS, page RC-200 (optional)
• Setting SPF Interval for a Single-Topology IPv4 and IPv6 Configuration, page RC-203 (optional)
• Customizing Routes for IS-IS, page RC-205 (optional)
• Configuring MPLS LDP IS-IS Synchronization, page RC-208 (optional)
• Enabling Multicast-Intact, page RC-210 (optional)
• Tagging IS-IS Interface Routes, page RC-211 (optional)