Re: IPv4 multicast best current practice I-D

[Marshall Eubanks <tme@21rst-century.com>]

Michael Luby wrote:

> In the PIM Sparse Mode section:
>
>    Within a PIM Sparse Mode domain, the standard PIM Sparse Mode
>    mechanisms are used to build shared forwarding trees and source
>    specific trees from IPv4 multicast sources to interested receivers.
>    IPv4 multicast sources are registered with the PIM Rendezvous Point
>    (RP).  Interested IPv4 multicast receivers make their group interest
>    known through the Internet Group Management Protocol, and the
>    associated PIM Designated Router (DR) sends PIM Join messages
>    towards the RP to build the appropriate forwarding trees.
>
>    In the ASM model, PIM Sparse Mode Rendezvous Points have to co-
>    operate in order to discover active sources and set up forwarding
>    trees.  MSDP is used to spread the knowledge of active sources
>    within a multicast group.  PIM-SM source-specific joins are used to
>    set up forwarding from sources towards the interested receivers.  No
>    inter-PIM-domain shared forwarding tree is created.
>
> The last part of this first paragraph is specific to ASM, yet this paragraph
> is written as if though it applies to IPv4 multicast in general.  There is
> no RP for SSM, there is no need for MSDP, etc.  The second paragraph is
> good, as it specifies what happens with ASM using MSDP and the RPs, etc.
> However, it seems logical that there should be a third paragraph for SSM
> that parallels this second paragraph for ASM, that says specifically there
> is no need for MSDP and RPs are not used and the forwarding tree is set up
> directly from the source to the receivers using PIM-SM (or PIM-SSM)
> source-specific joins.
>
> In the MSDP section, it should be specifically noted at the top that the
> bulk of this section only applies to ASM, and specifically SSM does not need
> (and should not use) MSDP.  Most of this section is ASM specific, and it
> should be specifically called out which parts apply to ASM and which parts
> apply to SSM.
>
> -----Original Message-----
> From: owner-wg-multicast@internet2.edu
> [mailto:owner-wg-multicast@internet2.edu]On Behalf Of Bill Nickless
> Sent: Sunday, April 01, 2001 8:16 PM
> To: msdp@network-services.uoregon.edu; wg-multicast@internet2.edu;
> mboned@network-services.uoregon.edu
> Subject: IPv4 multicast best current practice I-D
>
> -----BEGIN PGP SIGNED MESSAGE-----
>
> I have posted
>
>   http://www-fp.mcs.anl.gov/~nickless/draft-nickless-ipv4-mcast-bcp-00.txt
>
> to the internet-drafts@ietf.org and to the IETF mboned mailing
> list.  Please read it over and comment.
>
> ===
> Bill Nickless    http://www.mcs.anl.gov/people/nickless      +1 630 252 7390
> PGP:0E 0F 16 80 C5 B1 69 52 E1 44 1A A5 0E 1B 74 F7     nickless@mcs.anl.gov
>

Mike;

I will have comments on the draft soon; but these are my comments on your comments.