Cisco Cisco IOS Software Release 12.0(23)S

To specify what types of LSPs can use a backup tunnel, whether the backup tunnel should provide 
bandwidth protection, and if so, how much, use the tunnel mpls traffic-eng backup-bw command in 
interface configuration mode.

tunnel mpls traffic-eng backup-bw {bandwidth | [sub-pool {bandwidth | Unlimited}] 

[global-pool {bandwidth | Unlimited}]}

If neither sub-pool nor global-pool is entered, it is assumed that any LSP (those using bandwidth from 
the sub-pool or global-pool) can use this backup tunnel.

Interface configuration mode, on the backup tunnel interface

If both sub-pool and global-pool are specified, sub-pool must be specified first on the command line. 
For example, tunnel mpls traffic-eng backup-bw sub-pool 100 global-pool Unlimited is legal, but it 
is not legal to specify tunnel mpls traffic-eng backup-bw global-pool Unlimited sub-pool 100.

To limit both sub-pool and global pool LSPs, enter tunnel mpls traffic-eng backup-bw sub-pool 
bandwidth global-pool bandwidth.

If sub-pool is Unlimited, global-pool cannot also be Unlimited. Entering such a command (tunnel mpls 
traffic-eng backup-bw sub-pool Unlimited global-pool Unlimited) would be the same as entering 
nothing at all because it is the default behavior.

In the following example, backup tunnel 1 is to be used only by LSPs that take their bandwidth from the 
global pool. The backup tunnel does not provide bandwidth protection. Backup tunnel 2 is to be used 
only by LSPs that take their bandwidth from the sub-pool. Backup tunnel 2 provides bandwidth 
protection for up to 1000 units. 

Only LSPs using bandwidth from the global-pool can use the backup tunnel.

Only LSPs using bandwidth from the sub-pool can use the backup tunnel.

The amount of bandwidth this backup tunnel can protect. The router limits 
the LSPs that can use this backup tunnel so that the sum of the bandwidth 
of the LSPs does not exceed the specified amount of bandwidth. If there are 
multiple backup tunnels, the router will use the best-fit algorithm (see 

) to determine which backup tunnel 

to use.

Backup tunnel does not provide bandwidth protection. Any number of LSPs 
can use the backup tunnel, regardless of their bandwidth.

12.0(22)S

This command was introduced.