[c-nsp] Multicast state behavior differences between 7600 and ASR9k

[Phil Mayers]

On 28/02/11 15:35, John Neiberger wrote:

> Besides, it's my opinion that if there is a multicast sender on a
> port, then multicast state exists and we should be able to use a
> simple multicast show command to view the state.

If you're using SSM, what state exists when nothing is joined? There are 
no PIM asserts being sent to the PIM RP i.e. no (*,g).

Clearly the 7600 has a forwarding architecture that necessitates a 
null-OIF MRIB entry (guess: to prevent CPU punts); presumably the ASR9k 
doesn't have the same architecture, and just drops packets without an 
MRIB entry.

That doesn't mean it wouldn't be useful of course; but presumably the 
ASR9k would need to be leaking packets to the CPU to build this state in 
the first place, which has its own set of problems.