Related Topics
Configuring MPLS-TE Forwarding Adjacency, on page 277
Configure Forwarding Adjacency: Example, on page 349
MPLS-TE Forwarding Adjacency Restrictions
The MPLS-TE Forwarding Adjacency feature has these restrictions:
•
Using the MPLS-TE Forwarding Adjacency increases the size of the IGP database by advertising a TE
tunnel as a link.
•
The MPLS-TE Forwarding Adjacency is supported by Intermediate System-to-Intermediate System
(IS-IS).
•
When the MPLS-TE Forwarding Adjacency 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.
•
MPLS-TE forwarding adjacency tunnels must be configured bidirectionally.
•
Multicast intact is not supported with MPLS-TE Forwarding Adjacency.
MPLS-TE Forwarding Adjacency Prerequisites
Your network must support the following features before enabling the MPLS -TE Forwarding Adjacency
feature:
•
MPLS
•
IP Cisco Express Forwarding
•
Intermediate System-to-Intermediate System (IS-IS)
Unequal Load Balancing
Unequal load balancing permits the routing of unequal proportions of traffic through tunnels to a common
destination. Load shares on tunnels to the same destination are determined by TE from the tunnel configuration
and passed through the MPLS Label Switching Database (LSD) to the Forwarding Information Base (FIB).
Load share values are renormalized by the FIB using values suitable for use by the forwarding code. The
exact traffic ratios observed may not, therefore, exactly mirror the configured traffic ratios. This effect is
more pronounced if there are many parallel tunnels to a destination, or if the load shares assigned to those
tunnels are very different. The exact renormalization algorithm used is platform-dependent.
Note
There are two ways to configure load balancing:
Explicit configuration
Using this method, load shares are explicitly configured on each tunnel.
Cisco IOS XR MPLS Configuration Guide for the Cisco CRS Router, Release 5.1.x
184
Implementing MPLS Traffic Engineering
Unequal Load Balancing