Re: [tcpm] Further comments on draft-ietf-tcpm-accurate-ecn

Bob Briscoe <ietf@bobbriscoe.net> Wed, 18 July 2018 10:18 UTC

Return-Path: <ietf@bobbriscoe.net>
X-Original-To: tcpm@ietfa.amsl.com
Delivered-To: tcpm@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 7C4C813112E; Wed, 18 Jul 2018 03:18:03 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.989
X-Spam-Level:
X-Spam-Status: No, score=-1.989 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, T_KAM_HTML_FONT_INVALID=0.01, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=bobbriscoe.net
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id FZ32QM3d09GK; Wed, 18 Jul 2018 03:18:00 -0700 (PDT)
Received: from server.dnsblock1.com (server.dnsblock1.com [85.13.236.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 334C8130E2F; Wed, 18 Jul 2018 03:17:59 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=bobbriscoe.net; s=default; h=Content-Type:In-Reply-To:MIME-Version:Date: Message-ID:References:To:From:Subject:Sender:Reply-To:Cc: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=3Rs4Gz5gQYjZGv9bU641XxnHjJaaQ5/wGSkF7kiJOAc=; b=1qu4HOQ0HvDwPFtcMp30cS4jP umv33Q9hrFwGWv9JIvSfneRdXs2VLwKl9fbfAE+l7XaOHHEH+mnajFUkGckIjmfF3eL/k/ugWss3G IC4Yjy4GMWz+Xx5OJ6LuiQh7mEcXH5UAfFeKBVl0I6syBb9rb/LGxJA/8NaI9uav5JQGBE2lJUFST SQyXyyDBsj4Nsp9t0R4c4mEpQ2AHlgVsqdqcDiCs6AQl7pepNGmlLNnqjte7Ky8NziuC8vQVSuj+B ED8YM77uIS2pipfXIbYm16rsH7YyRzY2AfmGk+DpsaIFqD/IGQAQdOt9Sfcjo9iUBh+kAc63UWeRR 9eCgacqYA==;
Received: from mtrlpq426kw-lp140-01-65-94-232-118.dsl.bell.ca ([65.94.232.118]:59964 helo=[192.168.2.57]) by server.dnsblock1.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.91) (envelope-from <ietf@bobbriscoe.net>) id 1ffjWv-0006OY-H2; Wed, 18 Jul 2018 11:17:57 +0100
From: Bob Briscoe <ietf@bobbriscoe.net>
To: "Scharf, Michael (Nokia - DE/Stuttgart)" <michael.scharf@nokia.com>, "draft-ietf-tcpm-accurate-ecn@ietf.org" <draft-ietf-tcpm-accurate-ecn@ietf.org>, "tcpm@ietf.org" <tcpm@ietf.org>
References: <AM2PR07MB086725AB3E0DFF2CFFAAE07A935E0@AM2PR07MB0867.eurprd07.prod.outlook.com> <9cc642a7-10e9-3adb-2c49-4a52da9d206c@bobbriscoe.net> <VI1PR07MB0880170EF06C9CE1C63A464C935C0@VI1PR07MB0880.eurprd07.prod.outlook.com> <b9125c5a-d774-8d16-aec5-6712bd4bdb2f@bobbriscoe.net> <VI1PR07MB088038B7B4E017DCCF4F2718935C0@VI1PR07MB0880.eurprd07.prod.outlook.com> <c79e6b9f-c270-64b6-c6c0-1250b0c04fc6@bobbriscoe.net> <VI1PR07MB088008BBCA30D8391D31E302935C0@VI1PR07MB0880.eurprd07.prod.outlook.com> <fad5a5f9-b861-fc32-85e3-142212fb0113@bobbriscoe.net>
Message-ID: <2faf9b21-28ba-283c-3bea-8fd3941ccb40@bobbriscoe.net>
Date: Wed, 18 Jul 2018 06:17:56 -0400
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <fad5a5f9-b861-fc32-85e3-142212fb0113@bobbriscoe.net>
Content-Type: multipart/alternative; boundary="------------FC479EFC4512E0C5D180AC2D"
Content-Language: en-GB
X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname - server.dnsblock1.com
X-AntiAbuse: Original Domain - ietf.org
X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12]
X-AntiAbuse: Sender Address Domain - bobbriscoe.net
X-Get-Message-Sender-Via: server.dnsblock1.com: authenticated_id: in@bobbriscoe.net
X-Authenticated-Sender: server.dnsblock1.com: in@bobbriscoe.net
Archived-At: <https://mailarchive.ietf.org/arch/msg/tcpm/GIo0jVixS1wyU9dA9Xu9VBZg3sM>
Subject: Re: [tcpm] Further comments on draft-ietf-tcpm-accurate-ecn
X-BeenThere: tcpm@ietf.org
X-Mailman-Version: 2.1.27
Precedence: list
List-Id: TCP Maintenance and Minor Extensions Working Group <tcpm.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tcpm>, <mailto:tcpm-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tcpm/>
List-Post: <mailto:tcpm@ietf.org>
List-Help: <mailto:tcpm-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tcpm>, <mailto:tcpm-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 18 Jul 2018 10:18:04 -0000

Michael,

Sorry, I meant to add back in 'Therefore':

    It is recommended that the AccECN protocol is implemented alongside

    the experimental ECN++ protocol [I-D.ietf-tcpm-generalized-ecn 
<https://tools.ietf.org/html/draft-ietf-tcpm-accurate-ecn-07#ref-I-D.ietf-tcpm-generalized-ecn>].
    Therefore, this specification does not discuss implementing AccECN alongside
    [RFC5562], which was an earlier experimental protocol with narrower
    scope than ECN++.



Bob

On 18/07/18 06:14, Bob Briscoe wrote:
> Michael,
>
> That regains the problem I said I was trying remove, of risking 
> implying "AccECN could also be combined with RFC5562, but this isn't 
> the place to talk about it?", by not explaining that ECN++ subsumes 
> the function of RFC5562. How about:
>
>     It is recommended that the AccECN protocol is implemented alongside
>     the experimental ECN++ protocol [I-D.ietf-tcpm-generalized-ecn 
> <https://tools.ietf.org/html/draft-ietf-tcpm-accurate-ecn-07#ref-I-D.ietf-tcpm-generalized-ecn>].
>     This specification does not discuss implementing AccECN alongside
>     [RFC5562], which was an earlier experimental protocol with narrower
>     scope than ECN++.
>
>
>
> Bob
>
> On 17/07/18 17:01, Scharf, Michael (Nokia - DE/Stuttgart) wrote:
>>
>> This wording would imply that ECN++ and RFC 5562 are indeed 
>> “alternatives”. That is IMHO not fully correct, ECN++ seems to have a 
>> broader scope.
>>
>> I think something along the lines of …
>>
>>     It is recommended that the AccECN protocol is implemented alongside
>>     the experimental ECN++ protocol [I-D.ietf-tcpm-generalized-ecn 
>> <https://tools.ietf.org/html/draft-ietf-tcpm-accurate-ecn-07#ref-I-D.ietf-tcpm-generalized-ecn>].
>>     This specification does not discuss implementing AccECN
>>     alongside the experimental protocol [RFC5562].
>>
>> …does the job.
>>
>> Michael
>>
>> *From:*Bob Briscoe [mailto:ietf@bobbriscoe.net]
>> *Sent:* Tuesday, July 17, 2018 10:28 PM
>> *To:* Scharf, Michael (Nokia - DE/Stuttgart) 
>> <michael.scharf@nokia.com>om>; draft-ietf-tcpm-accurate-ecn@ietf.org; 
>> tcpm@ietf.org
>> *Subject:* Re: [tcpm] Further comments on draft-ietf-tcpm-accurate-ecn
>>
>> Michael,
>>
>> OK RECOMMENDED -> recommended.
>> That's good, otherwise I think ECN++ would have become a normative 
>> reference.
>>
>>
>>     Alternatively, a more statement not related to the status would
>>     be “a combination of AccECN with RFC 5562 is outside the scope of
>>     this document”.
>>
>> Someone who had never even thought about combining AccECN with 
>> RFC5562 might think we mean "AccECN could also be combined with 
>> RFC5562, but this isn't the place to talk about it?"
>>
>> How about:
>>
>>     It is recommended that the AccECN protocol is implemented alongside
>>     the experimental ECN++ protocol [I-D.ietf-tcpm-generalized-ecn 
>> <https://tools.ietf.org/html/draft-ietf-tcpm-accurate-ecn-07#ref-I-D.ietf-tcpm-generalized-ecn>].
>>     Therefore, this specification does not discuss implementing AccECN
>>     alongside the earlier experimental alternative to ECN++ in [RFC5562].
>>
>>
>>
>>
>>
>> Bob
>>
>> On 17/07/18 08:57, Scharf, Michael (Nokia - DE/Stuttgart) wrote:
>>
>>     I would prefer the first, shorter wording.
>>
>>     For instance, it would be possible that TCPM decides to obsolete
>>     RFC 5562. I’d suggest to keep the status and future use of RFC
>>     5562 in combination with ECN++ outside of this document.
>>
>>     What might be in scope of the AccECN spec would be a hypothetical
>>     use of AccECN in combination with RFC 5562. But I would be fine
>>     with just omitting that. Alternatively, a more statement not
>>     related to the status would be “a combination of AccECN with RFC
>>     5562 is outside the scope of this document”.
>>
>>     Actually, I am also not sure if this paragraph is a good example
>>     for RECOMMENDED in a capital letters. To me, the following would
>>     be sufficient:
>>
>>         It is recommended that the AccECN protocol is implemented along with
>>
>>         the experimental ECN++ protocol [I-D.ietf-tcpm-generalized-ecn
>>     <https://tools.ietf.org/html/draft-ietf-tcpm-accurate-ecn-07#ref-I-D.ietf-tcpm-generalized-ecn>].
>>
>>     Michael
>>
>>     *From:*Bob Briscoe [mailto:ietf@bobbriscoe.net]
>>     *Sent:* Tuesday, July 17, 2018 2:43 PM
>>     *To:* Scharf, Michael (Nokia - DE/Stuttgart)
>>     <michael.scharf@nokia.com> <mailto:michael.scharf@nokia.com>;
>>     draft-ietf-tcpm-accurate-ecn@ietf.org
>>     <mailto:draft-ietf-tcpm-accurate-ecn@ietf.org>; tcpm@ietf.org
>>     <mailto:tcpm@ietf.org>
>>     *Subject:* Re: [tcpm] Further comments on
>>     draft-ietf-tcpm-accurate-ecn
>>
>>     Michael,
>>
>>     I've written the proposed edits into a local copy of draft-08,
>>     which we'll post after this IETF.
>>
>>     Wile writing the last point, I thought it best to add an extra
>>     sentence.
>>
>>         It is RECOMMENDED that the AccECN protocol is implemented along with
>>
>>         the experimental ECN++ protocol [I-D.ietf-tcpm-generalized-ecn
>>     <https://tools.ietf.org/html/draft-ietf-tcpm-accurate-ecn-07#ref-I-D.ietf-tcpm-generalized-ecn>].
>>
>>         [I-D.ietf-tcpm-generalized-ecn] is a proposed alternative to another
>>
>>         experimental scheme [RFC5562] so there is no need to implement RFC
>>
>>         5562 along with AccECN.
>>
>>       
>>
>>
>>
>>     Bob
>>
>>     On 17/07/18 01:05, Scharf, Michael (Nokia - DE/Stuttgart) wrote:
>>
>>         This would for for me.
>>
>>         Thanks
>>
>>         Michael
>>
>>         *From:*Bob Briscoe [mailto:ietf@bobbriscoe.net]
>>         *Sent:* Tuesday, July 17, 2018 1:34 AM
>>         *To:* Scharf, Michael (Nokia - DE/Stuttgart)
>>         <michael.scharf@nokia.com> <mailto:michael.scharf@nokia.com>;
>>         draft-ietf-tcpm-accurate-ecn@ietf.org
>>         <mailto:draft-ietf-tcpm-accurate-ecn@ietf.org>; tcpm@ietf.org
>>         <mailto:tcpm@ietf.org>
>>         *Subject:* Re: [tcpm] Further comments on
>>         draft-ietf-tcpm-accurate-ecn
>>
>>         Michael,
>>
>>         On 15/07/18 16:54, Scharf, Michael (Nokia - DE/Stuttgart) wrote:
>>
>>             Hi all,
>>
>>               
>>
>>             While reading draft-ietf-tcpm-accurate-ecn-07, I noticed the following:
>>
>>               
>>
>>               
>>
>>             Section 1. Introduction
>>
>>               
>>
>>                 It is likely (but not required) that the AccECN protocol will be
>>
>>                 implemented along with the following experimental additions to the
>>
>>                 TCP-ECN protocol: ECN-capable TCP control packets and retransmissions
>>
>>                 [I-D.ietf-tcpm-generalized-ecn], which includes the ECN-capable SYN/
>>
>>                 ACK experiment [RFC5562]; and testing receiver non-compliance
>>
>>                 [I-D.moncaster-tcpm-rcv-cheat].
>>
>>               
>>
>>             [ms] I have commented on this section before. And I still dislike the term "likely". To me, "likely" is speculation. A neutral phrasing would be "... it is possible..." or "... it is useful...". Having said this, I observe that draft-moncaster-tcpm-rcv-cheat-03 was last updated in 2014. How "likely" is it that the AccECN protocol will be implemented along with a mechanism documented in an ID that has been written more than 10 years ago and not been updated for about 4 years? Are implementers indeed so interested in draft-moncaster-tcpm-rcv-cheat that an implementation is "likely"?
>>
>>
>>         I agree. For ECN++, I think something like your suggestion of
>>         "useful", or even RECOMMENDED is what is needed here. I think
>>         the testing receiver compliance one could be removed from the
>>         intro. It's mentioned under testing for unexpected
>>         interference and under integrity checking, which are sufficient.
>>
>>         Also, this makes me notice that the word "includes" is wrong.
>>         ECN++ intends to obsolete RFC5562, but I don't think we need
>>         to mention that here (cos it might change before ECN++ gets
>>         published).
>>
>>         CURRENT TEXT:
>>
>>             It is likely (but not required) that the AccECN protocol will be
>>
>>             implemented along with the following experimental additions to the
>>
>>             TCP-ECN protocol: ECN-capable TCP control packets and retransmissions
>>
>>             [I-D.ietf-tcpm-generalized-ecn
>>         <https://tools.ietf.org/html/draft-ietf-tcpm-accurate-ecn-07#ref-I-D.ietf-tcpm-generalized-ecn>], which includes the ECN-capable SYN/
>>
>>             ACK experiment [RFC5562 <https://tools.ietf.org/html/rfc5562>]; and testing receiver non-compliance
>>
>>             [I-D.moncaster-tcpm-rcv-cheat
>>         <https://tools.ietf.org/html/draft-ietf-tcpm-accurate-ecn-07#ref-I-D.moncaster-tcpm-rcv-cheat>].
>>
>>         PROPOSED TEXT:
>>
>>             It is RECOMMENDED that the AccECN protocol is implemented along with
>>
>>             the experimental ECN++ protocol [I-D.ietf-tcpm-generalized-ecn
>>         <https://tools.ietf.org/html/draft-ietf-tcpm-accurate-ecn-07#ref-I-D.ietf-tcpm-generalized-ecn>].
>>
>>
>>
>>
>>
>>               
>>
>>               
>>
>>               
>>
>>             Section 2.1.  Capability Negotiation
>>
>>                 
>>
>>                 The TCP server sends the AccECN
>>
>>                 Option on the SYN/ACK and the client sends it on the first ACK to
>>
>>                 test whether the network path forwards the option correctly.
>>
>>               
>>
>>             [ms] According to Section 3.2.6, options are RECOMMENDED. While Section 2 is not normative, the whole Section 2 does not really describe well the actual requirements regarding options. This paragraph in Section 2.1 is one example for that. It would make sense to be more explicit in Section 2 to which extent options have to be supported.
>>
>>         OK, we need to review section 2, to ensure it is consistent
>>         with changes that have been made in the normative section 3
>>         since it was written.
>>
>>         In this particular case, we already promised to check
>>         (offlist with an implementer) that there was no text that
>>         contradicted the optionality of the option stated at the end
>>         of Section 3.2.6.
>>
>>         I have already started this with a list I prepared (also
>>         offlist) of which middlebox checking sections an implementer
>>         could ignore if they were only reading but not sending the
>>         TCP options.
>>
>>
>>
>>
>>         Bob
>>
>>
>>
>>
>>
>>         -- 
>>
>>         ________________________________________________________________
>>
>>         Bob Briscoehttp://bobbriscoe.net/
>>
>>
>>
>>
>>     -- 
>>
>>     ________________________________________________________________
>>
>>     Bob Briscoehttp://bobbriscoe.net/
>>
>>
>>
>> -- 
>> ________________________________________________________________
>> Bob Briscoehttp://bobbriscoe.net/
>
> -- 
> ________________________________________________________________
> Bob Briscoehttp://bobbriscoe.net/

-- 
________________________________________________________________
Bob Briscoe                               http://bobbriscoe.net/