Re: Multicast Graft and Prune Override

Thanks a ton for ur explanation. Nailed it finally

wat is meant by ACCESS CONCENTRATOR?

On Mon, Nov 21, 2011 at 11:51 PM, Carlos G Mendioroz <tron_at_huapi.ba.ar>wrote:

> Kid,
> routers running PIM-DM to receive a previously pruned (S,G).
>
> -Carlos
>
> CCIE KID @ 21/11/2011 15:18 -0300 dixit:
>
>> Hi Carlos,
>>
>> Thanks for the info. One more thing who send this graft message and for
>> what reason they use this GRAFT message?
>>
>>
>> On Mon, Nov 21, 2011 at 11:41 PM, Carlos G Mendioroz <tron_at_huapi.ba.ar<mailto:
>> tron_at_huapi.ba.ar>> wrote:
>>
>> The problem is not determining the destination ADDRESS of the GRAFT,
>> but
>> the INTERFACE you use to send it. You need to send it on RPF(S), but
>> if you don't know S, then there's no way to know RPF(S).
>> (And don't you dare think of flooding it :)
>>
>> GRAFT is part of PIM-DM. Hosts have no business in this mantra.
>>
>> -Carlos
>>
>> CCIE KID @ 21/11/2011 14:55 -0300 dixit:
>>
>> Hi Carlos,
>>
>> U got my question right. What is the destination IP address for
>> Graft message. I thought it is 224.0.0.2 --All ROuters address
>> and i didnt thought about the Server Source address .. So when
>> Flooding happens, the FHR router will flood it to all hosts and
>> hosts catch hold of that flood and then they can send a IGMP
>> join towards FHR right. Instead of that why does it send GRAFT
>> message?
>> And wat is the use of Graft message?
>>
>> On Mon, Nov 21, 2011 at 11:16 PM, Carlos G Mendioroz
>> <tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>
>> <mailto:tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>>> wrote:
>>
>> Kid,
>> you asked why is there flooding if you could use GRAFT instead.
>> (at least that was my interpretation of your Q1).
>>
>> My answer is that for you to be able to send a GRAFT, you need
>> to
>> know where to send it to, but you learn that because of
>> flooding.
>> If there were no flooding, the router would never learn the
>> sources
>> of different groups, so you would not know where to GRAFT to.
>>
>> BTW, the "client" message is GRAFT, no GRAFT ACK. GRAFT ACK
>> is sent
>> back to acknowledge reception by the upstream router.
>>
>> -Carlos
>>
>> CCIE KID @ 21/11/2011 14:32 -0300 dixit:
>>
>> hi carlos,
>>
>> not able to get u man in the first answer. Wat is the use of
>> graft and graft ack message. could u elaborate man
>>
>> On Mon, Nov 21, 2011 at 7:34 PM, Carlos G Mendioroz
>> <tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>
>> <mailto:tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>>
>> <mailto:tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>
>> <mailto:tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>>>> wrote:
>>
>> Kid,
>>
>> 1) you don't know S before you ever receive a mcast
>> packet.
>> So you
>> can not tell who to send a graft (no RPF interface).
>>
>> 2) sounds good to me. Two receivers on the same
>> segment and one
>> decides to PRUNE makes the other shout (JOIN) not to be
>> forgotten :)
>>
>> -Carlos
>>
>> CCIE KID @ 21/11/2011 08:21 -0300 dixit:
>>
>> Hi fellas,
>>
>> I was reading my Multicast theory and i have few
>> doubts
>> with the
>> Dense
>> mode.
>>
>> 1)There is a Graft Ack message sent by the client
>> to rejoin a
>> particular
>> group , ( becasue already he is a member and then
>> pruned and
>> then again
>> joining ) , . At this point the First hop router
>> should send
>> just a Graft
>> Ack message to rejoin the group. If there is Graft
>> concept. Why
>> there is
>> the concept of Flooding n Pruning for every 3
>> minutes??
>>
>> Because Graft Ack just solves the purpose of
>> joining again
>> instead of
>> waiting for 3 minutes for the FHR to send the feed
>> again.
>> Can some explain me the use of Graft message and
>> Graft Ack in
>> Multicast
>>
>>
>> 2)Regarding Prune Override .. If there are more
>> than two
>> routers
>> say R1 and
>> R2 in a LAN domain. R3 is used as as the FHR
>> towards the
>> RP Now
>> if a host
>> connected to R1 is sending a IGMP Leave message
>> and now
>> R1 sends
>> a Group
>> specific query and if there is no host which
>> replies to this
>> query, now
>> then R1 will send a PIM prune message to 224.0.0.2
>> and now R2
>> receives it
>> and now it see that there is a host which is actively
>> participating in that
>> group and it sends a Prune override to R3 and now R3
>> still sends
>> traffic on
>> the link.
>>
>> Correct me if i am wrong in the above statement.
>> Can some one
>> explain my
>> understanding is correct or not.
>>
>> R3------------------| Sw1
>> |---------------R1--------Host 1
>> |
>> |
>> |
>> R2
>> |
>> |
>> |
>> Host 2
>> This is my scenario
>>
>>
>> With Warmest Regards,
>>
>> CCIE KID
>> CCIE#29992 (Security)
>>
>>
>> Blogs and organic groups at http://www.ccie.net
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>>
>>
>>
>>
>>
>>
>> -- Carlos G Mendioroz <tron_at_huapi.ba.ar
>> <mailto:tron_at_huapi.ba.ar>
>> <mailto:tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>>
>> <mailto:tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>
>>
>> <mailto:tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar>>>>
>>
>>
>> LW7 EQI Argentina
>>
>>
>>
>>
>> -- With Warmest Regards,
>>
>> CCIE KID
>> CCIE#29992 (Security)
>>
>>
>>
>> -- Carlos G Mendioroz <tron_at_huapi.ba.ar
>> <mailto:tron_at_huapi.ba.ar> <mailto:tron_at_huapi.ba.ar
>> <mailto:tron_at_huapi.ba.ar>>>
>> LW7 EQI Argentina
>>
>>
>>
>>
>> -- With Warmest Regards,
>>
>> CCIE KID
>> CCIE#29992 (Security)
>>
>>
>>
>> -- Carlos G Mendioroz <tron_at_huapi.ba.ar <mailto:tron_at_huapi.ba.ar
>> >>
>> LW7 EQI Argentina
>>
>>
>>
>>
>> --
>> With Warmest Regards,
>>
>> CCIE KID
>> CCIE#29992 (Security)
>>
>>
>>
> --
> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>

-- 
With Warmest Regards,
CCIE KID
CCIE#29992 (Security)
Blogs and organic groups at http://www.ccie.net