Cisco Cisco IOS Software Release 12.0(22)S

There are multiple methods to ensure bandwidth protection. Cisco implementation of FRR does not 
mandate a particular bandwidth protection method. However, it is important that the method you choose 
is consistent with the bandwidth protection strategy you choose. 

The following sections describe some important issues to consider when choosing an appropriate 
configuration:

When using the explicitly signaled bandwidth method, you must configure the following two bandwidth 
parameters for a backup tunnel:

Signaled bandwidth 

Backup-bandwidth 

The signaled bandwidth is used by the LSRs on the path of the backup tunnel to perform admission 
control and bandwidth accounting. 

The backup-bandwidth is used by the PLR (the head-end of the backup tunnel) to decide how much 
primary traffic can use this backup tunnel if there is a failure. 

You must configure both parameters, and the values of signaled bandwidth and backup-bandwidth must 
be the same.

To configure signaled bandwidth, use the tunnel mpls traffic-eng bandwidth command. 

To configure backup-bandwidth, use the tunnel mpls traffic-eng backup-bw command.

Configuring signaled bandwidth allows you to specify both of the following:

Amount of bandwidth a backup tunnel reserves 

Pool (global pool or sub-pool) from which the backup tunnel reserves its bandwidth

Only one pool can be selected (that is, the backup tunnel can explicitly reserve bandwidth from the 
global pool or the sub-pool, but not both). 

Configuring backup-bandwidth allows you to specify the pool to which the traffic must belong in order 
to use this backup tunnel. Multiple pools are allowed. 

You can configure different pools for signaled bandwidth and backup-bandwidth of the same backup 
tunnel.

Example—Assume the following:

Bandwidth protection is desired only for sub-pool traffic. Best-effort traffic uses the global pool and 
does not require bandwidth protection.

Scheduling is configured so that sub-pool traffic uses the priority queue, and global pool traffic is 
served at a lower priority.

Bandwidth protection for 10 Kbps of sub-pool traffic on a given link can be achieved by any of the 
following command combinations: