Re: msdp sa message

Hello and good evening wonderful team,

A quick question for clarification on the RPF check that each MSDP peer
would do in a larger network w/ multiple autonomous systems (or a CCIE
scenario) ...

Lets say you have two separate AS, and YOU ARE NOT sharing all routes
between. There is no default or summary routes between the two AS.

MSDP peers share info and each learns about another source in the other AS.
Here is my confusion:

1) In this scenario, won't you have a RPF failure or will each MSDP peer
simply drop the advertisement since they do not know anything about the
others source?

2) If using BGP to overcome any RPF failures or to solve this scenario, do
you only have to advertise the source address from the other AS?

I believe you have to advertise each sending source address ...

3) Does each RP/MSDP peer become the next hop then in the BGP table?

Sorry team ... my lab is not up and running yet.

I am also interested in hearing others comments, gotchas, and good advice.
Many TIA team and have a good night,

Andrew

On Thu, Jan 27, 2011 at 3:36 PM, abderrahim sadki <sadkia_at_gmail.com> wrote:

> Thank you Narbik and Brian. It is clear.
>
> Abderrahim
>
>
> On 01/26/2011 01:23 AM, Brian McGahan wrote:
>
>> The only action taken is that the (S,G) entry is installed in the SA
>> cache. MSDP is just used to tell the RPs where the sources are, it doesn't
>> have anything to do with building the tree. PIM is still used for the
>> formation of the tree, which occurs once the RP receives a (*,G) PIM join
>> for a group that is in the SA cache. The (S,G) entry will then be installed
>> in the multicast routing table, and the (S,G) tree joined back to the
>> source.
>>
>>
>> HTH,
>>
>> Brian McGahan, CCIE #8593 (R&S/SP/Security)
>> bmcgahan_at_INE.com
>>
>>
>> -----Original Message-----
>> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
>> abderrahim sadki
>> Sent: Tuesday, January 25, 2011 2:24 PM
>> To: ccielab_at_groupstudy.com
>> Cc: sadkia_at_gmail.com
>> Subject: msdp sa message
>>
>> Hi all,
>>
>> After going through the multicast configuration guide I am a bit confused:
>>
>> When the MSDP peer receives the SA message from the other domain, does he
>> send
>> a (S,G) join message back to the RP? or does it decapsulate it and
>> forwards it
>> to the receivers.
>>
>> Thanks,
>> Abderrahim
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
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-- 
Andrew Lee Lissitz
all.from.nj_at_gmail.com
Blogs and organic groups at http://www.ccie.net