Re: [tcpm] 793bis and RFC3168

Gorry Fairhurst <gorry@erg.abdn.ac.uk> Thu, 07 October 2021 11:45 UTC

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From: Gorry Fairhurst <gorry@erg.abdn.ac.uk>
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Date: Thu, 7 Oct 2021 12:45:07 +0100
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Subject: Re: [tcpm] 793bis and RFC3168
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On 07/10/2021 12:39, t petch wrote:
> On 07/10/2021 08:55, Gorry Fairhurst wrote:
>> On 06/10/2021 13:00, tom petch wrote:
>>> Does 793bis warrant an
>>> Updates 3168?
>>>
>>> It does change the format of the IANA registry as created by RFC3168
>>> and so would seem an update.  I realise that the IANA registry will
>>> point to 793bis; I am unclear whether the revised registry will have
>>> any mention of RFC3168 not that it changes my view on Updates.
>>>
>>> Tom Petch
>>> _______________________________________________
>>> tcpm mailing list
>>> tcpm@ietf.org
>>> https://www.ietf.org/mailman/listinfo/tcpm
>>
>> Thanks for asking, I looked at this.
>>
>> RFC 3168 gave initial contents of the registry and stated:
>>
>>     The Transmission Control Protocol (TCP) included a 6-bit Reserved
>>     field defined inRFC 793
>> <https://datatracker.ietf.org/doc/html/rfc793>, reserved for future use,
>> in bytes 13 and 14
>>     of the TCP header, as illustrated below.  The other six Control bits
>>     are defined separately byRFC 793
>> <https://datatracker.ietf.org/doc/html/rfc793>.
>>
>> This could have been handled more elegantly, but  I think the RFC3168
>> text remains correct, in that the base TCP spec (RFC793, or it's bis)
>> define the 6 other bits.  To me, there is no change to the meaning of
>> RFC3168 intended by 793bis, and I think updating a reference would not
>> need to be flagged as an update.
>
> Yeees, I was looking at the format where 'Bit' is updated to 'Bit 
> Offset' and 'Assignment Notes' is added.  An update?  Perhaps not.
>
> Tom Petch
>
>> Best wishes,
>>
>> Gorry Fairhurst
>>
>> (as co-chair tsvwg).
>>
Thanks for your quick reply. I defer to the Wes/TCPM chairs to say if 
this is needed. If it is, then please do liaise with TSVWG to ensure the 
update is consistent with the expectations of TSVWG.

Gorry