TE and Multicast
Multicast packets are not sent over TE tunnels, but over the underlying physical infrastructure. This can cause problems with multicast's Reverse-Path Forwarding (RPF) lookup when autoroute is enabled.
Multicast does its forwarding by doing an RPF lookup on the source address of every multicast packet. It forwards that packet only if it came in on the interface that the routing table says is the shortest path to the source.
The problem with this and TE, though, is that if you enable autoroute, your routing table points to a bunch of routes out a TE tunnel, but packets never come in on TE tunnels! Multicast breaks! Bad!
With autoroute disabled, things look like Example 10-14.
Example 10-14. Routing and RPF Information with No ...
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