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Re: IPv6 link-scoped multicast

On Thu, 5 Aug 2004, Myung-Ki Shin wrote:
> As for the issue #2,
> our main goal is to *generate* unique multicast addresses - /96
> automatically (like RFC 3306) without any fear of conflicts.

"Any fear" is subjective.  It is completely possible that a node 
might start to send an SSM stream to that particular multicast 

> o Multicast source side
>    1. Link-local address
>      - FE80::a12:34ff:fe56:7890
>    2. Predefined/static group id
>      - Channel 1 -> 1
>    3. Source can get unique multicast addresses - /96
>      - FF32:00ff:a12:34ff:fe56:7890::/96
>    4. Session creation
>      - FF32:00ff:a12:34ff:fe56:7890::1
> o Multicast receiver side
>    1. Predefined/static group id
>      - Channel 1 -> 1
>    2. *Source discovery*
>      - LLMNR + predefined group id
>    3. Join
>      - FF32:00ff:a12:34ff:fe56:7890::1

So, the group ID appears to be communicated out of band.

What is the name of the session?  Why cannot the source check from
LLMNR whether such a session, or such an address under that session
does not already exist? (This is why I was stating that this kind of 
problems appear to be trivially solved as part of source discovery.)

Apart from that..

Can you provide a bit of details what you're actually obtaining from 
LLMNR?  Does the source register the address 
FF32:00ff:a12:34ff:fe56:7890::1 there, and just join to what you 

If so, there is really no requirement for embedding EUI64 on the
address, it's just something that's assumed to be reasonably unique.

A constructive suggestion: reword this spec to use the upper bits of 
FF02::/16, even embedding the EUI64 if you wish, and publish it as an 
Informational RFC if you think an RFC is really needed.

Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

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