Cisco Cisco IOS Software Release 12.0(13)S7

If one of the neighbors is known to take 6 minutes to detect the restart and to clear stale forwarding 
information, you would want to increase the timeout values.

See the 

 for instructions for setting the 

timeout period for safe MPLS label reuse.

If no record of previous label use exists, the default behavior is for the router to proceed as though all 
MPLS labels were in use before the restart and prevent the allocation of any label until the safe-to-reuse 
timer expires. You might want to change the router behavior to proceed as though no labels were in use 
before the reload for the same reasons that you might want to disable the feature:

The problem of unsafe MPLS label reuse following a router restart is unlikely to occur in your 
network. 

The number of MPLS labels available immediately after restart does not meet the need for labels in 
your network and you are willing to accept the possibility that MPLS traffic might be misforwarded 
for a short period following a router restart.

See the 

for information on choosing how the router should proceed when no record of previous label usage 
exists.

You can also select the method by which the MPLS label allocator allocates pblocks and the labels 
corresponding to the pblocks. If you do not explicitly configure an allocation algorithm, the platform 
specifies the default algorithm to be used. 

 describes the allocation algorithms provided by the 

MPLS Safe Label Reuse After Router Restart feature.

Exhaust Available 

The MPLS label allocator allocates the smallest free label from the set of 
in-use pblocks and allocates all labels corresponding to those pblocks before 
requesting more pblocks.

This algorithm typically uses fewer pblocks than the other algorithms, 
making more pblocks available following restart than the other algorithms at 
the cost of a sparsely allocated label space.