Re: [tcpm] draft-ietf-tcpm-accurate-ecn-24 addressing all WGLC comments

[[e-mail]]

> On 30. Mar 2023, at 16:53, Bob Briscoe <[e-mail]> wrote:
> 
> Michael, Yoshi, Ian (as tcpm chairs),
> 
> To close off the WGLC, I have just posted a new rev of accurate-ecn. Hyperlinks quoted at the end.
> You will see the diff is rather extensive. I won't give a summary of all the diffs like I usually do. Instead I can just refer to the summary I gave in the presentation on Monday:
> https://datatracker.ietf.org/meeting/116/materials/slides-116-tcpm-draft-ietf-tcpm-accurate-ecn
> 
> Thank you again to the people who reviewed this during the WGLC:
> Michael Tüxen, Alex Burr, Gorry Fairhurst and Markku Kojo.
> 
> All changes are editorial, apart from removing the para about not mistaking certain ACKs of ACKs for DupACKs, which I will add to a rev of the ECN++ draft, hopefully later this week.
> 
> On the list, we have seen agreement from all the reviewers to these changes, except no response from Markku yet.
> On Monday, I told Markku that I would post the draft in a few days, so everyone can see the updates and diff.
Anyone having additional comments? In particular Markku regarding loss recovery?

Best regards
Michael
> 
> Cheers
> 
> 
> Bob
> 
> On 30/03/2023 15:15, [e-mail] wrote:
>> A New Internet-Draft is available from the on-line Internet-Drafts
>> directories. This Internet-Draft is a work item of the TCP Maintenance and
>> Minor Extensions (TCPM) WG of the IETF.
>> 
>>    Title           : More Accurate Explicit Congestion Notification (ECN) Feedback in TCP
>>    Authors         : Bob Briscoe
>>                      Mirja Kühlewind
>>                      Richard Scheffenegger
>>    Filename        : draft-ietf-tcpm-accurate-ecn-24.txt
>>    Pages           : 64
>>    Date            : 2023-03-30
>> 
>> Abstract:
>>    Explicit Congestion Notification (ECN) is a mechanism where network
>>    nodes can mark IP packets instead of dropping them to indicate
>>    incipient congestion to the endpoints.  Receivers with an ECN-capable
>>    transport protocol feed back this information to the sender.  ECN was
>>    originally specified for TCP in such a way that only one feedback
>>    signal can be transmitted per Round-Trip Time (RTT).  Recent new TCP
>>    mechanisms like Congestion Exposure (ConEx), Data Center TCP (DCTCP)
>>    or Low Latency, Low Loss, and Scalable Throughput (L4S) need more
>>    accurate ECN feedback information whenever more than one marking is
>>    received in one RTT.  This document updates the original ECN
>>    specification in RFC 3168 to specify a scheme that provides more than
>>    one feedback signal per RTT in the TCP header.  Given TCP header
>>    space is scarce, it allocates a reserved header bit previously
>>    assigned to the ECN-Nonce.  It also overloads the two existing ECN
>>    flags in the TCP header.  The resulting extra space is exploited to
>>    feed back the IP-ECN field received during the 3-way handshake as
>>    well.  Supplementary feedback information can optionally be provided
>>    in two new TCP option alternatives, which are never used on the TCP
>>    SYN.  The document also specifies the treatment of this updated TCP
>>    wire protocol by middleboxes.
>> 
>> The IETF datatracker status page for this Internet-Draft is:
>> https://datatracker.ietf.org/doc/draft-ietf-tcpm-accurate-ecn/
>> 
>> There is also an htmlized version available at:
>> https://datatracker.ietf.org/doc/html/draft-ietf-tcpm-accurate-ecn-24
>> 
>> A diff from the previous version is available at:
>> https://author-tools.ietf.org/iddiff?url2=draft-ietf-tcpm-accurate-ecn-24
>> 
>> Internet-Drafts are also available by rsync at rsync.ietf.org::internet-drafts
>> 
>> 
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> 
> -- 
> ________________________________________________________________
> Bob Briscoe                               http://bobbriscoe.net/
>