Re: iewb lab 12 Q6.3 anycast rp

From: Bogdan Sass (bogdan.sass@catc.ro)
Date: Fri Sep 19 2008 - 03:42:39 ART


ricky ong wrote:
> Hi all,
> I got some problems when working on IEWB VOL2 4.1 LAB 12 Q6.3. The question calls for anycast RP configuration. After configuring i realized that I can ping a multicast group joined on R6 from SW2 (225.26.26.26). I got the MSDP peer up but it seems that multicast routing table is not exchanged between the two MSDP peer (R4, R5).
> I referred to the solution guide and was a bit surprised to find the below explanation:
>
> "When R4's lo is up, sw2 will not be able to ping 226.26.26.26 since the group is using R4 as RP and sw2 is using R5 as RP."
> Yes this is a problem, but isn't it the reason why MSDP is configured?
>
> "Now we will shutdown R4's lo which will mean R6 will use R5 as the RP "
> How can we provide RP redundancy then if multicast can not flow with two RP up at the same time?
>
>
    I had the same "problem" while doing the lab. From what I read about
anycast RP, this is actually the normal, expected behavior (the
information about sources/clients is passed between the RPs via MSDP, so
any router can ping any multicast group).

    So I can only assume that the SG is wrong on this one.

-- 
Bogdan Sass
CCAI,CCNP,CCSP,JNCIA-ER
Information Systems Security Professional
"Curiosity was framed - ignorance killed the cat"

Blogs and organic groups at http://www.ccie.net



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