Re: msdp sa message

A tip: use "*ip msdp mesh-group"* command to overcome MSDP RPF problems in
the lab.

So nice of Jeff Doyle to mention that... :)

HTH,
Dan #13685 (RS/Sec/SP)
 The CCIE troubleshooting blog: http://dans-net.com

On Fri, Jan 28, 2011 at 8:55 PM, Brian McGahan <bmcgahan_at_ine.com> wrote:

> Whether the SA is accepted or not uses a more complicated logic than a
> normal
> RPF check. It is RFC defined, and you can see more info about it here:
> http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gt_msdp.html
>
>
> HTH,
>
> Brian McGahan, CCIE #8593 (R&S/SP/Security)
> bmcgahan_at_INE.com
> Internetwork Expert, Inc.
> http://www.INE.com
> Toll Free: 877-224-8987 x 705
> Outside US: 775-826-4344 x 705
>
> From: ALL From_NJ [mailto:all.from.nj_at_gmail.com]
> Sent: Thursday, January 27, 2011 9:33 PM
> To: abderrahim sadki
> Cc: Brian McGahan; abderrahim sadki; ccielab_at_groupstudy.com; Narbik
> Kocharians
> Subject: 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<mailto: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>
> [mailto: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<mailto:ccielab_at_groupstudy.com>
> Cc: sadkia_at_gmail.com<mailto: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
>
>
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>
>
>
>
>
> --
> Andrew Lee Lissitz
> all.from.nj_at_gmail.com<mailto:all.from.nj_at_gmail.com>
>
>
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Received on Fri Jan 28 2011 - 21:01:11 ART