Re: [tcpm] Extending TCP option space

[Joe Touch <[e-mail]>]

Some further clarification:

On 8/31/2011 11:13 AM, William Allen Simpson wrote:
> On 8/31/11 9:57 AM, Pasi Sarolahti wrote:
>> TCP's option space has been under increasing demand recently, with new
>> option-space hungry extensions such as MPTCP, and some recent ideas in
>> the research domain. In the past there have been some discussion about
>> mechanisms to extend the option space, and an extension option was
>> proposed in draft-eddy-tcp-loo, but since then these efforts have died
>> down. I'm wondering if there would be any interest in the tcpm
>> community to resume this work.
>>
> Already done, already tested. RFC-6013.

This extends options after then SYN exchange. That has always been 
trivial, but doesn't address the SYN space.

I.e., this is Wed Eddy's LO, not SLO.

>> I recall that re-segmenting middleboxes were mentioned as one
>> potential problem for such extension, and there might be other
>> problems. Nevertheless, I would find it useful, if there was an RFC
>> that a) documented the known problems with option space extension; and
>> b) defined an option format and assigned the needed type codes, to
>> enable experimentations with larger than 40-byte option space.

Experiments SHOULD be using options 253 and 254, as per RFC 4727; i.e., 
those option numbers are already available for experiments.

Joe