Re: sink RP...

Ronald,

If you have a static RP defined, the auto-RP groups will not inherently act
in dense mode.

R9(config)#ip pim rp-address 200.200.200.9

R9#sho ip mroute 224.0.1.40 | be \(
(*, 224.0.1.40), 00:09:05/00:00:14, RP 200.200.200.9, flags: SJCL <----- S
for Sparse
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    Serial1/1, Forward/Sparse-Dense, 00:09:05/00:00:14

Consider the following topology: R4---R6---R9 with R4 as RP (via auto-RP)

With each router having a sink RP as its own loopback, the auto-RP groups
operate in sparse-mode. R9 thinks of itself as RP, so it never sends any
joins up to R6. R6 never populates its OIL for the auto-RP groups with R9's
interface. R4 sends RP mapping messages to R6, but R6 does not forward them
because the OIL for those groups is NULL. R9 never learns of the real RP and
cannot join any multicast groups being registered at R4.

On Mon, Sep 7, 2009 at 7:33 AM, Ronald Johns <rj686b_at_att.com> wrote:

> Cool - that's what I thought. The proctor guide answer had an ACL
> configured to deny the Auto-RP addresses and I couldn't figure out why.
> (IPexpert Vol 3 Lab 4 Task 5.2) Thanks for clearing this up!
>
> - Ron
>
> -----Original Message-----
> From: Scott Morris [mailto:smorris_at_ine.com]
> Sent: Monday, September 07, 2009 6:53 AM
> To: Hoogen
> Cc: Jacob Uecker; Ronald Johns; ccie forum
> Subject: Re: sink RP...
>
> Right... So by that mere definition alone, you won't need to worry
> about excluding the Auto-RP addresses from the sink-hole due to the fact
> that they are SENT in dense mode, regardless.... So there won't be an
> inherent need to "join" those groups via an RP. Therefore you won't
> sinkhole yourself.
>
> ;)
>
>
>
>
> *Scott Morris*, CCIE/x4/ (R&S/ISP-Dial/Security/Service Provider) #4713,
>
> JNCIE-M #153, JNCIS-ER, CISSP, et al.
>
> JNCI-M, JNCI-ER
>
> evil_at_ine.com
>
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-- 
Bryan Bartik
CCIE #23707 (R&S), CCNP
Sr. Support Engineer - IPexpert, Inc.
URL: http://www.IPexpert.com
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