Re: [v6ops] new draft: draft-taylor-v6ops-fragdrop

[Joe Touch <[e-mail]>]

On 11/7/2012 7:07 AM, Brian E Carpenter wrote:
....
>> Except for extension headers that are yet to be defined.
>
> I don't get your point, Joe. It is very clear in 2460 that extension
> headers are only interpreted at the destination, except for the HBH
> options header.

That was not at all clear from RFC2460, however, your pointer to 6564 
corrects that omission (sorry I hadn't caught that).

> So there's no scope to develop a new header with HBH
> semantics. In any case, this is already covered in RFC 6564:
>    "New IPv6 extension
>     header(s) having hop-by-hop behavior MUST NOT be created or
>     specified.  New options for the existing Hop-by-Hop Header SHOULD NOT
>     be created or specified unless no alternative solution is feasible."
>
>      Brian

There's remains other problematic language in 2460, however:

    Each extension header should occur at most once, except for the
    Destination Options header which should occur at most twice (once
    before a Routing header and once before the upper-layer header).

So it still seems open to have more than one HBH header, which certainly 
complicates things even though they'd be clearly marked.

Joe