From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Wed Jul 14 2004 - 14:28:55 GMT-3
Yes this is true. The behavior is the same regardless of sparse
or dense. This is why design-wise it is recommended to use
point-to-point ip subnets for your WAN links. For situations where this
is not an option, sparse-mode PIM has a feature known as NBMA mode.
With PIM NBMA mode, the Outgoing Interface List (OIL) in the
multicast routing table is associated with the PIM neighbor's IP address
instead of the outgoing interface itself. This means that if Spoke-A
with IP address 1.2.3.4 requests a join for group 224.1.1.1, Spoke-B
with IP address 5.6.7.8 will not receive the traffic. Likewise is
Spoke-B sends a prune message for 224.1.1.1, it will not affect Spoke-A.
PIM NBMA can be used when you are running sparse or sparse-dense
PIM, however it will only apply to groups that are actually running in
sparse-mode, as the explicit join messages that are inherent to
sparse-mode are what allows NBMA mode to function properly.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> gladston@br.ibm.com
> Sent: Wednesday, July 14, 2004 10:53 AM
> To: ccielab@groupstudy.com
> Subject: Prune in Dense Mode Partial Meshed
>
> I understand the problem that arises when a spoke router sends a Prune
> message to the Hub in a partial-meshed FR subnet, causing a second
spoke
> to lost multicast packets because it did not see the Prune.
>
> I am trying to figure out why it is different with Sparse-mode. As I
view
> it if R1 (hub) receives a message from R2 (spoke A) to stop sending
> multicast out Serial0, R3 (spoke B) will not hear the message either,
as
> it occurs with Dense-mode.
>
>
> Any Tip?
>
>
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