Re: [tcpm] Early assignment of IANA TCP option number for AccECN

[Michael Tuexen <[e-mail]>]

> On 25. Jul 2022, at 17:31, Bob Briscoe <[e-mail]> wrote:
> 
> tcpm, Michael,
> 
> On 25/07/2022 15:08, Scheffenegger, Richard wrote:
>> 
>> 
>> Am 25.07.2022 um 16:02 schrieb Michael Tuexen:
>>>> On 25. Jul 2022, at 15:52, Scheffenegger, Richard <[e-mail]> wrote:
>>>> 
>>>> 
>>>> Hi,
>>>> 
>>>> As one of the authors of the AccECN draft, which approaches the final
>>>> stages, I wanted to see if there is support to ask IANA for an early
>>>> assignment of the two TCP Option numbers for AccECN.
>>>> 
>>>> The background here is, that the current use of the experimental option
>>>> in Linux (0xACC0 and 0xACC1) is not really documented - the draft only
>>>> mentiones the experimental ID 0xACCE which was in use prior of the
>>>> decision to go with two distinct option numbers.
>>> If I understand the experimental options correctly, you could just use
>>> kind=253, ExID=0xACCE
>>> kind=254, ExID=0xACCE
>>> to distinguish your two option using the assignment already made (for
>>> example the kind=253 for Order 0, kind=254 for Order 1).
>> 
>> Yes, could have :)
>> 
>>> I don't see the ones used by Linux under
>>> https://www.iana.org/assignments/tcp-parameters/tcp-parameters.xhtml#tcp-exids 
>> 
>> No. I went to
>> 
>> https://github.com/L4STeam/linux/blob/testing/include/net/tcp.h
>> 
>> to find the currently in use experiment IDs as observed in the interop
>> testing.
> 
> Richard told me that earlier today he asked IANA to document the two exIDs at https://www.iana.org/assignments/tcp-parameters/tcp-parameters.xhtml#tcp-exids
> Which is why I also documented them in the draft update I just sent.
Hi Bob,

in my earlier e-mail I missed this sentence! Thank you very much for documenting
them!

Best regards
Michael
> However, IANA hasn't updated that registry yet, AFAICT.
> 
> 
> Bob
> 
>> 
>>>> 
>>>> However, the implementations between Linux and FreeBSD deviated - Linux
>>>> using two different experimental IDs (see above), while the FreeBSD
>>>> variant differentiated by an additional byte after the experiment ID
>>>> (0xACCE).
>>> I think the draft should describe how to use the experimental options.
>>> 
>>> Best regards
>>> Michael (as an individual)
> 
> -- 
> ________________________________________________________________
> Bob Briscoe                               http://bobbriscoe.net/
>