[c-nsp] MVPN

Christian Meutes christian at qunec.net
Wed Oct 29 05:56:31 EDT 2008


>> 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.
>
> Really? That's got to be a bug. What platform are you on?

What should be the behavior if no bug would be insolved? Continue to stream 
the new group to the default-mdt?

>> 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.
>
> You seem to be mis-understanding how PIM-SM works. When a source starts
> up, only the *first few* packets are tunneled via the RP; these few are
> forwarded down the shared tree, which triggers the other PEs to do a join
> to source, and the traffic then flows optimally; the RP will then send a
> Register-Stop to the PE of the source, which stops the tunneling.

No Iam not mis-understanding how PIM-SM works :-)

What i tried to explain was that if no more than 255 data-mdt's can be 
created how can I stream to more than 255 multicast groups: Only solution 
would be to do it without a data-mdt which would result in forwarding 
everything over the Core-RP (default-mdt) with PIM-SM or to do it in 
PIM-SSM and forward everything to every PE but at least on the shortest 
reverse-path (SPT).






More information about the cisco-nsp mailing list