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

[Michael Tuexen <[e-mail]>]

> On 26. Jul 2022, at 04:33, Scheffenegger, Richard <[e-mail]> wrote:
> 
> 
> For completeness, IANA has updated the registry earlier today too:
> 
> https://www.iana.org/assignments/tcp-parameters/tcp-parameters.xhtml#tcp-parameters-1
Perfect. Thanks for letting us know.

Best regards
Michael
> 
> 
> Am 25.07.2022 um 22:45 schrieb Michael Tuexen:
>>> On 25. Jul 2022, at 22:39, Bob Briscoe <[e-mail]> wrote:
>>> 
>>> Michael,
>>> 
>>> On 25/07/2022 17:49, Michael Tuexen wrote:
>>>>> 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.
>>>>> However, IANA hasn't updated that registry yet, AFAICT.
>>>> It might take them a while.
>>>> 
>>>> But if someone uses exIDs for early deployments of an ID, the ID should
>>>> specify how the exIDs should be used... Any chance to do that? Or does
>>>> it not make any sense anymore?
>>> 
>>> [BB] The rev of the draft that we submitted this morning does that - apologies that we omitted to do this in earlier drafts.
>>> It's written as it needs to be if/when it becomes an RFC, but it's hopefully clear which exIDs are used for which option in the mean time, or until an early assignment.
>> Yes, I'm happy. Just missed it before sending my reply. Thank you very much for adding the text.
>> Adding support for the option to packetdrill right now...
>>> 
>>> Quickest to see the diff:
>>> https://www.ietf.org/rfcdiff?url2=draft-ietf-tcpm-accurate-ecn-20.txt
>> That is actually how I found it. But too late..
>> 
>> Again: Thanks a lot!
>> 
>> Best regards
>> Michael
>>> 
>>> Bob
>>> 
>>>> 
>>>> Best regards
>>>> Michael
>>>>> 
>>>>> 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/
>>>>> 
>>> 
>>> --
>>> ________________________________________________________________
>>> Bob Briscoe                               http://bobbriscoe.net/
>>> 
>>