Subject: draft on IPv6 multicast issues

From: Pekka Savola <[email-masked]>
Date: Mon, 7 Oct 2002 16:25:22 +0300 (EEST)

Hello all,

I've just sent a 7-page draft on IPv6 Multicast Deployment Issues to
[email-masked].  In the meantime, it's available at:

http://www.netcore.fi/pekkas/ietf/draft-savola-v6ops-multicast-issues-00.txt

The abstract is:

   There are many issues concerning the deployment and implementation,
   and to a lesser degree, specification of IPv6 multicast.  This memo
   describes known problems, trying to raise awareness.  Currently,
   global IPv6 interdomain multicast is completely impossible except
   using SSM: there is no way to convey information about multicast
   sources between PIM RPs. Site-scoped multicast is also problematic
   when used alongside to global multicast because of that.  A few
   possible solutions are outlined or referred to.  In addition, an
   issue regarding link-local multicast-blocking Ethernet switches is
   brought up.  Finally, a feature request for MLD snooping switches is
   noted.

The companion document on embedding the address of the RP in the multicast
address will follow shortly.

Comments are welcome, either directly or to the list(s) if appropriate.

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords

---

From: Bill Nickless <[email-masked]>
Date: Mon, 07 Oct 2002 11:19:03 -0500

At 04:25 PM 10/7/2002 +0300, Pekka Savola wrote:
>[email-masked].

Please also see

ftp://ftp.ietf.org/internet-drafts/draft-ietf-mboned-iesg-gap-analysis-00.txt

Here's the abstract:

     An overview of IP multicast as deployed in the Internet today,
     from the perspective of the MBONED working group. Existing
     infrastructure is examined critically. Suggestions for possible
     improvement of the overall architecture are presented for the IESG.

IPv6 multicast is included in this analysis.

One of the concepts presented is that IGMP and MLD snooping might be 
discouraged, due to the complexity it requires on the part of the Ethernet 
switches.  (Namely, interpretation of IPv4 and IPv6 datagrama.)

Another concept presented is to change the many-to-one static mapping 
between IPv[46] multicast group addresses and IEEE MAC addresses, in favor 
of a dynamic mapping much like IPv4 ARP or IPv6 Neighbor Discovery.

===
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     [email-masked]

---

From: Pekka Savola <[email-masked]>
Date: Tue, 8 Oct 2002 14:24:04 +0300 (EEST)

Hello,

> IPv6 multicast is included in this analysis.

Thanks for the pointer, I had come across it earlier but hadn't looked 
into it much deeper.
 
> switches.  (Namely, interpretation of IPv4 and IPv6 datagrama.)

Agreed.
 
> of a dynamic mapping much like IPv4 ARP or IPv6 Neighbor Discovery.

This seems more like "nice to have in the future" issue, not absolutely 
criticial for present deployment.

I'm adding appropriate pointers in the next revision, though.

Thanks.