RE: WG LC: draft-ietf-l3vpn-2547bis-mcast-bgp

["NAPIERALA, MARIA H, ATTLABS" <[e-mail]>]

PIM-SM/RFC 4601 permits, quote, "a receiver to join a group and specify
that it only wants to receive traffic for a group if that traffic comes
from a particular source. If a receiver does this, and no other receiver
on the LAN requires all the traffic for the group, then the DR may omit
performing a (*,G) join to set up the shared tree, and instead issue a
source-specific (S,G) join only."

Such behavior of end systems in PIM-SM means that a PE can receive Join
(C-S, C-G) even for sources that are not active. 

Section 13.1 of draft-ietf-l3vpn-2547bis-mcast-bgp-05 requires that
"whenever a PE creates an <C-S,C-G> state as a result of receiving a
Source Tree Join C-multicast route for <C-S, C-G> from some other PE,
the PE that creates the state MUST originate a Source Active A-D route."

The procedure as described in section 13.1 might lead to useless S-PMSI
creation for C-sources operating in sparse groups which are not active.
This procedure should be enhanced to prevent triggering of S-PMSIs in
such cases.

Maria

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf
> Of Danny McPherson
> Sent: Friday, November 21, 2008 8:52 AM
> To: [e-mail]
> Subject: WG LC: draft-ietf-l3vpn-2547bis-mcast-bgp
> 
> 
> Please consider today the start of a 2-week last call
> for draft-ietf-l3vpn-2547bis-mcast-bgp, available here:
> 
> http://tools.ietf.org/html/draft-ietf-l3vpn-2547bis-mcast-bgp-05
> 
> Input on this draft's suitability for publication as an
> Internet Standards Track document is solicited, feedback
> ends December 9, 2008.
> 
> Thanks in advance for your feedback!
> 
> Danny & Marshall