Cisco Cisco IOS Software Release 12.0(23)S

The following sections describe how to use FRR to protect LSPs in your network from link or node 
failures. Each task is identified as either required or optional.

 (required)

 (required) 

 (optional) 

 (optional)

You can perform the configuration tasks in any order. 

An NNHOP backup tunnel must not go via the NHOP. 

LSPs can use backup tunnels only if they have been configured as fast reroutable. To do this, enter the 
following commands, beginning in global configuration mode, at the headend of each LSP: 

To create a backup tunnel to the next hop or to the next-next hop, enter the following commands on the 
node that will be the headend of the backup tunnel (that is, the node whose downstream link or node 
may fail). The node on which you enter these commands must be a supported platform. See 

. 

Creating a backup tunnel is basically no different from creating any other tunnel. None of the commands 
below is new.

When using the exclude-address command to specify the path for a backup tunnel, the exclude-address 
must exclude an interface address to avoid a link (for creating an NHOP backup tunnel), or a router-ID 
address to avoid a node (for creating an NNHOP backup tunnel).

Router(config)# interface tunnel number

Enters interface configuration mode for the 
specified tunnel.

Router(config-if)# tunnel mpls traffic-eng 

Enables the tunnel to use a backup tunnel if there 
is a link or node failure.