Subject: WG Action - 1 week last call [LL13] If the destination is a global multicast address a host SHOULD use a global source address

From: Erik Guttman <[email-masked]>
Date: Thu, 3 Apr 2003 18:19:20 +0200 (CEST)

This item is entering a 1 week last call discussion period, ending Apr
10, 2003.  Please send a comment to the working group list indicating
whether you accept or reject the proposal, including more information if
appropriate.  Please use the subject line:

  [LL13] If the destination is a global multicast address a host SHOULD
use a global source address

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In light of LL23, this goes without saying.  Do you agree?

In case LL23 gets revisited, please do express your opinion of
this item.
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Description of Issue  If the destination is a global multicast address a
host SHOULD use a global source address    
Submitter Name  Erik Nordmark
Submitter Email Address  [email-masked]    
Date first submitted 6 Feb 2003    
Reference
http://www.merit.edu/mail.archives/zeroconf/2002-10/msg00000.html
Comment Type ['T'echnical | 'E'ditorial]  T    
Priority['S' Must fix | '1' Should fix | '2' May fix ]  S    
Section  2.6
Rationale/Explanation of issue:   
Lengthy description of problem: 

If the destination address is the 255.255.255.255 broadcast address or a
multicast address, then the host may use either its link-local source
address or a routable address, as appropriate. 

OK for a link-local multicast destination. But for other multicast
destinations I assume it SHOULD use any routable address instead of
the link-local. 

Requested Change: 

If the destination address is the 255.255.255.255 broadcast address or a
link-local multicast address, then the host may use either its
link-local source address or a routable address, as appropriate. If the
destination address is a multicast address with scope larger than
link-local then the host SHOULD use an appropriate routable source
address, if available, or its link-local source address otherwise. 

Erik Guttman 
Zeroconf WG chair

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From: "Philip Nye" <[email-masked]>
Date: Fri, 4 Apr 2003 11:12:27 -0000

> address, if available, or its link-local source address otherwise.

What is a link-local multicast address? how would the host know whether a
multicast address is being routed?

If a LL multicast means the 24.0.0/24 link-local scoped multicast prefix
then the text should say so with a reference.

Philip

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From: Robert Elz <[email-masked]>
Date: Sat, 05 Apr 2003 19:53:38 +0700

I support LL13.   Wording the text to correctly refer to multicast
addresses with a link scope would be a good idea, and a reference to
the multicast docs where that is defined, essential, but those are
just nits.

It might also be worth pointing out that an "available routable address"
for multicast purposes has tighter requirements than an available
routable address for just about any other use imaginable - the routable
address needs to be assigned to (or at least, routed in via) the interface
through which the multicast packet is to be forwarded, or it won't be
correctly processed.

kre

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From: Erik Guttman <[email-masked]>
Date: Fri, 11 Apr 2003 15:11:51 +0200 (CEST)

Action: Accept

Note:   A proper reference for link-local multicast is needed.
        RFC 2365 describes this scope.  There may be a better
        reference (normative) - but I do not know it.

Erik Guttman
Zeroconf WG chair

--------------------------------

On Thu, 3 Apr 2003, Erik Guttman wrote:
> Subject: WG Action - 1 week last call [LL13] If the destination is a global multicast address a host SHOULD use a global source address
> 

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