Re: Question about <draft-ietf-6man-deprecate-atomfrag-generation-03>

[Tore Anderson <[e-mail]>]

* Bob Hinden <[e-mail]>

> You may be reading this out of context.  The start of this section
> starts with:
> 
>    IPv6 requires that every link in the internet have an MTU of 1280
>    octets or greater.
> 
> RFC443 ICMPv6 that defines the ICMP Packet too Big message references
> RFC1981 Path MTU Discovery (also referenced in this section) says:
> 
>    A node MUST NOT reduce its estimate of the Path MTU below the IPv6
>    minimum link MTU.
> 
> I think this makes it clear what to do if an ICMP Packet Too Big
> message is received with an MTU less than 1280.

Quite. Thank you for this clarification.

Then I can say that your proposed changes to -01 draft works for me. 

> However, this then goes on to say:
> 
>       Note: A node may receive a Packet Too Big message reporting a
>       next-hop MTU that is less than the IPv6 minimum link MTU.  In
> that case, the node is not required to reduce the size of subsequent
>       packets sent on the path to less than the IPv6 minimun link MTU,
>       but rather must include a Fragment header in those packets
> [IPv6- SPEC].
> 
> That would also need to be updated (that is, remove this note), or
> file an errata once the rfc2460bis is done.  The latter would be
> easier.

Agreed. I had missed this fact that RFC1981 mandates the generation of
atomic fragments. That should probably have been pointed out in
draft-ietf-6man-deprecate-atomfrag-generation.

Tore