Cisco Cisco IOS Software Release 12.0(15)S

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      MPLS Traffic Engineering Forwarding Adjacency
Configuration Examples
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Cisco IOS Release 12.0(15)S
Usage Tips
Figure 2
Using Forwarding Adjacencies 
In 
, if you have no forwarding adjacencies configured for the TE tunnels between B-F and C-F, 
all the traffic that A has to forward to F goes through B since B is the shortest path from A to F. (The 
cost from A to F is 15 through B and 20 through C.)
If you have forwarding adjacencies configured on the TE tunnels between B-F and C-F and also on the 
TE tunnels between F-B and F-C, then when A computes the SPF algorithm, A sees two equal cost paths 
of 11 to F. As a result, traffic across the A-B and A-C links is shared.
5 = IS-IS metric for each physical link
6 = IS-IS metric for the TE tunnels
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