Cisco Cisco IOS Software Release 12.0(15)S
MPLS Traffic Engineering Forwarding Adjacency
Feature Overview
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Cisco IOS Release 12.0(15)S
Figure 1
Forwarding Adjacency Topology
As a result, a TE tunnel is advertised as a link in an IGP network with the link’s cost associated with it.
Routers outside of the TE domain see the TE tunnel and use it to compute the shortest path for routing
traffic throughout the network.
traffic throughout the network.
Benefits
TE Tunnel Interfaces Advertised for SPF
TE tunnel interfaces are advertised in the IGP network just like any other links. Routers can then use
these advertisements in their IGPs to compute the SPF even if they are not the head end of any TE
tunnels.
these advertisements in their IGPs to compute the SPF even if they are not the head end of any TE
tunnels.
Restrictions
•
Using the MPLS TE Forwarding Adjacency feature increases the size of the IGP database by
advertising a TE tunnel as a link.
advertising a TE tunnel as a link.
•
The MPLS TE Forwarding Adjacency feature is supported by Intermediate System-to-Intermediate
System (IS-IS). Open Shortest Path First (OSPF) support will be available in a future release.
System (IS-IS). Open Shortest Path First (OSPF) support will be available in a future release.
•
When the MPLS TE Forwarding Adjacency feature is enabled on a TE tunnel, the link is advertised
in the IGP network as a Type Length Value (TLV) 22 without any TE sub-TLV.
in the IGP network as a Type Length Value (TLV) 22 without any TE sub-TLV.
•
MPLS TE forwarding adjacency tunnels must be configured bidirectionally.
= IGP cloud
= Tunnels
= Routers
= Links
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