Subject: New draft on embedding the RP address in IPv6 multicast address

From: Pekka Savola <[email-masked]>
Date: Thu, 10 Oct 2002 14:21:44 +0300 (EEST)

Hello,

Me and Brian Haberman have submitted a new draft to
[email-masked]. In the interim, it's available at:

http://www.netcore.fi/pekkas/ietf/draft-savola-mboned-mcast-rpaddr-00.txt

         "Embedding the Address of RP in IPv6 Multicast Address"

Abstract                                               

   As has been noticed, there is exists a huge deployment problem with
   global, interdomain IPv6 multicast: PIM RPs have no way of         
   communicating the information about multicast sources to other
   multicast domains, as there is no MSDP, and the whole interdomain Any
   Source Multicast model is rendered unusable; SSM avoids these        
   problems.  This memo outlines a way to embed the address of the RP in
   the multicast address, solving the interdomain multicast problem. The
   problem is three-fold: specify an address format, adjust the         
   operational procedures and configuration if necessary, and modify
   receiver-side PIM implementations.  In consequence, there would be no
   need for interdomain MSDP.             

It's 9 pages.

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

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From: "Marshall Eubanks" <[email-masked]>
Date: Thu, 10 Oct 2002 08:11:54 -0400

[ post by non-subscriber.  with the massive amount of spam, it is easy to
  miss and therefore delete mis-posts.  so fix subscription addresses! ]

On Thu, 10 Oct 2002 14:21:44 +0300 (EEST)
> Hello,

Dear Pekka;

   A quick question about Section 4 :

  o "plen" MUST NOT be 0 (ie. not SSM)

     o "plen" MUST NOT be greater than 96

   The address of the RP can be obtained from a multicast address by
   taking the following steps:

      1. take the last 96 bits of the multicast address

      2. zero the last 128-"plen" bits, and

      3. replace the last 4 bits with the contents of "RPad".

If "plen" is = 1 (say), which seems to be allowed, then how do
I zero the last 127 bits of a 96 bit slice of a multicast address ?

I am pretty sure this is not what you mean, but this is what I read it to say.

Regards
Marshall Eubanks

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From: Pekka Savola <[email-masked]>
Date: Thu, 10 Oct 2002 15:20:11 +0300 (EEST)

> I am pretty sure this is not what you mean, but this is what I read it to say.

The first bullet makes it implicit that those 96 bits are placed at the 
beginning of a 128-bit address struct (which is assumed to have been 
initialized to zero).

But that should be clarified so there will be no misunderstandings, 
thanks.