Subject: (IPng 6682) W.G. Last Call on "Transmission of IPv6 over IPv4 Domains without Explicit Tunnels"

From: Bob Hinden <[email-masked]>
Date: Mon, 02 Nov 1998 09:09:14 -0800

This is a IPng working group last call for comments on advancing the
following document as a Proposed Standard:

	Title		: Transmission of IPv6 over IPv4 Domains 
                       without Explicit Tunnels
	Author(s)	: B. Carpenter, C. Jung
	Filename	: draft-ietf-ipngwg-6over4-00.txt
	Pages		: 9
	Date		: 29-Oct-98

Please send substantive comments to the ipng mailing list, and minor
editorial comments to the author.  This last call period will end two
week from today on November 16, 1998.

Bob Hinden / Steve Deering

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From: Erik Nordmark <[email-masked]>
Date: Mon, 2 Nov 1998 16:08:01 -0800 (PST)

The draft (in the second paragraph in section 7) is hand waving that the
protocol can be used in the absense of IPv4 multicast support.
I don't see how that can possibly be used without additional configuration
information. For instance, consider the bootstrapping scenario:
  A dual host is booting. It wants to send an IPv6 Router Solicitation to
  the all router group. 1) How does the host know whether or not IPv4 multicast
  is supported in the site/subnet? It can always send IPv4 multicast packets
  on the wire. 2) Even once it somehow determines that IPv4 multicast is not 
  supported how does the host determine the IPv4 unicast address(es) of the
dual 
  router(s) so that it can replicate and send the Router Solicitation 
  using IPv4 unicast?

I'd suggest completely removing that paragraph since this should be a protocol
spec and not contain hand waving arguments of what might be possible without
specifying or referring to the needed mechanisms and protocol elements.

Perhaps the title should also be changed to 
	Transmission of IPv6 over IPv4 Multicast Domains without Explicit Tunnels

   Erik

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From: Brian E Carpenter <[email-masked]>
Date: Tue, 03 Nov 1998 11:38:26 +0000

Erik,

I'm fairly convinced that the hand waving could be turned into
a complete definition, but it would be a bunch of work which is
not obviously justified by a requirement. Personally I'd be happy
to follow your suggestion, if my co-author and the WG agree.

   Brian