[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: IPv4 multicast best current practice I-D
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
-----BEGIN PGP SIGNATURE-----
Version: PGPfreeware 6.5.8 for non-commercial use <http://www.pgp.com>
iQCVAwUBOsfu2awgm7ipJDXBAQH6xgP9FOBW07KbnHRIXQODPkOjm80XHeKBIpnJ
z+QeObthJsgaeqgPiZUTJJRYrfneQcfYb8WGiKrhRkepoLK5jDZf2GNg8GBDAo7G
HoIHMvazttzUJC+onCyvGr8VZhgx6TgDQbp18/sjWOxtZtorWnAFFeE0AC5vQovA
Ddv+/au40pw=
=FOYB
-----END PGP SIGNATURE-----