Subject: RE: IPv6 WG Last Call on "IPv6 Global Unicast Address Format for the 2000::/3 Prefix"

From: "Michel Py" <[email-masked]>
Date: Thu, 20 Feb 2003 19:55:32 -0800

Alain,

> Alain Durand
> RFC2374 was the definition of addresses for Format Prefix
> 001 (2000::/3) which is formally made historic by this document.
> Although, as specified in [ARCH], IANA should limit the IPv6
> Global Unicast address space to 2000::/3 for now, the rest of
> the unassigned IPv6 address space should be treated as Global
> Unicast.

This is dangerous, IMHO. What we do not want is developers hardcoding
2000::/3 in their implementations; we don't know what the needs of
tomorrow are though. If someone invents a killer app that requires
allocating a /3 to multicast or anycast, your text would have to be
revised. There is indeed a difference between unassigned and treated as
Global Unicast. Currently unassigned parts of the IPv6 space should not
be treated as anything.

Michel.

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From: Alain Durand <[email-masked]>
Date: Thu, 20 Feb 2003 22:19:28 -0800

Oddly enough, from the same premises we arrived to opposite conclusions!
If you leave the space out of 2000::/3 as 'unassigned' and I'm an
implementor, I may put special code when sending a unicast
packet to make sure that SRC & DST addresses are within the valid 
range...

	- Alain.