[c-nsp] m-vpn

[Phil Mayers]

On 29/05/12 17:14, Aaron wrote:
> Please help me on a side-note....
>
> I've been wondering, what makes ssm ssm?  I mean here's what I was
> seeing....

SSM is configurable on a range of groups. Effectively, all it means is 
"don't make *,g joins for this group". s,g joins are made via other 
methods, for example IGMPv3 LAN clients, or discovery of "s" (i.e. the 
IP of other PEs) when running MVPN.

>
> I have several mcast groups in my network currently...all 239.x.x.x
>
> Thus far my mcast network was simply ...
>
> Mcast xmitter------>asr9k----------------asr9k----------mcast rcvr
>
> That's it.  Just a 2 router network with asr9k's directly connected in the
> middle with the source and destination of mcast traffic directly connected
> to both the respective asr9k's.
>
> I now want to virtualize that traffic from source to destination in a L3VPN
> (mcast enabled of course, which I believe makes it a mvpn by definition) but
> before proceeding just want to understand what I have currently.
>
> If I type "sh pim gr" I see all of the groups as "SM".  Interestingly I have

SM being "sparse mode", I assume?

> *NO* rp defined in my 2 mcast routers currently.  Isn't it a well know fact
> that you can not accomplish pim sm without an rp ??! (that's why I have my

No. SSM *is* sparse-mode. It's just sparse mode without *,g joins.

> doubts that "sh pim gr" is telling me the truth, but please tell me if I'm
> wrong)

I assume the ASR was able to discover the source of the other PE, and 
perform an s,g join. I wonder if it's using the older type-2 RDs, or 
something else, or if it worked "by chance".