[c-nsp] MVPN

Christian Meutes christian at qunec.net
Tue Oct 28 14:14:04 EDT 2008

Hi Phil,

> As far as I can see, SSM would only be of specific help if the >255
> groups were coming from >1 PE. You'd still have problems with >255 groups
> on 1 PE using SSM.

Even then I could use different data-mdt's for every PE in same VRF in
SM mode or not?

> The traffic will not flow via the RP, since all the PEs should have
> joined towards the other PEs for the default or data group in question.
> The issue is that some traffic might be sent to PEs which have no
> interest in it (if you have more active MVPN groups than data groups, or
> if it's flowing in the mdt default) but it will still flow on the source
> tree in the P-space, not the shared tree.
> Whether that's actually a problem depends on the bit rate of the traffic,
> number of PEs and types of links. Not the most helpful answer I'm afraid.

I just tested it in SM mode. What happens is that no more streams can be
send because of the exhaustion of all data-mdt's. Switchover to data-mdt
is configured to 1 and as soon as traffic arrives a data-mdt is tried
to open and unfortunately fails therefore.

The only solution as far as I can see is to do SSM without a data-mdt.
Sure I could also use SM without a data-mdt but that would concentrate
everything on the RP which would be the worst case of all.

Or do I miss something?


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