Re: [tsvwg] path forward on L4S issue #16

Wesley Eddy <wes@mti-systems.com> Tue, 23 June 2020 04:39 UTC

Return-Path: <wes@mti-systems.com>
X-Original-To: tsvwg@ietfa.amsl.com
Delivered-To: tsvwg@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 03A053A1739 for <tsvwg@ietfa.amsl.com>; Mon, 22 Jun 2020 21:39:27 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.9
X-Spam-Level:
X-Spam-Status: No, score=-1.9 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=unavailable autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=mti-systems-com.20150623.gappssmtp.com
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 7NfB_U-abrsd for <tsvwg@ietfa.amsl.com>; Mon, 22 Jun 2020 21:39:25 -0700 (PDT)
Received: from mail-qk1-x72c.google.com (mail-qk1-x72c.google.com [IPv6:2607:f8b0:4864:20::72c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 612933A173B for <tsvwg@ietf.org>; Mon, 22 Jun 2020 21:39:25 -0700 (PDT)
Received: by mail-qk1-x72c.google.com with SMTP id b4so17676593qkn.11 for <tsvwg@ietf.org>; Mon, 22 Jun 2020 21:39:25 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mti-systems-com.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=CKL2mSr49qR87yxC+diZTsKyzS9wlVqLL2EIEBLEbK0=; b=i6uGNYIVibF49f3qIS8tL6/6EoWVGYLOlS3Wx8AB81nSoW6WUmsBongnr3Uoy1wqSq 6HwaqE/fsucHdGEp6/7HyjShO+Pb61A1ZHFEi66tyT16Fg/wvjeEoq1uDc3o7ef5xzT8 HKVmOBRYjmNwOO5gX+IgKwZ3BGcjsBK3sGCRwOnhbC8fub9tGnXzGOL3mWohaCiVXUc0 Gc4D+c1sCMOPrI+TeZ0QKJlkz+8ygA+Wm6qUKZvY6bbxlUAfv4b5vTZ9IqpJFHpFKCKP FA3NjNYBCmakNkoKxArcoXNf2TcKOuaJy4sqB5UFaXFgJIU0X4Nwk4/Cgnq5NkFn8+yD BGtQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=CKL2mSr49qR87yxC+diZTsKyzS9wlVqLL2EIEBLEbK0=; b=an33W2zXfsU17kNbign54C2Pq/Q4ilywG16LzhsNG8cIg9tnm/Zjs0m5FvkTkGggLL W9LvcSDMshzm0AoCYQ4s7CmarCht3dbXdwzTV5i0tEFO0vXsBUUj34qIWoqz6+zqF9jO IOz20LX+u7rrsCgLZClmDcMPygoc40+jd9Da2ENVxXydU9NKr6YbpMak1Z/C4I7t5TBG pMkmj1PS1wn6GMeAqfr39TrUTTwW9ndgBl20igMxEx9RnDrR+rzhEGNc0Tva6Ydoa3cb RFc83luN13Pk44uQNq7yzHEDc5tkVjxfzCGa/AVthitFc1mnBAEF9/dQkOE8IX5oy41c bf/A==
X-Gm-Message-State: AOAM531fV8bh17mo7EXSG0CJJ8eDwEgOkPC5gucs77jTDJarXEzBiBhP rlT63EBlnKLgp6NO9qCop6hK1IbcPx4cRQ==
X-Google-Smtp-Source: ABdhPJyLTgSFrPxU1BatGB0JreJJWgVHGEU3YQoxVCp3tHgluqkMvGcQSwi9bEiWvVCculxwko/LqQ==
X-Received: by 2002:a37:a78c:: with SMTP id q134mr19759658qke.368.1592887164295; Mon, 22 Jun 2020 21:39:24 -0700 (PDT)
Received: from [192.168.1.12] (user-12l31c7.cable.mindspring.com. [69.81.133.135]) by smtp.gmail.com with ESMTPSA id 19sm12839598qke.44.2020.06.22.21.39.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 22 Jun 2020 21:39:23 -0700 (PDT)
To: "Rodney W. Grimes" <ietf@gndrsh.dnsmgr.net>
Cc: "Holland, Jake" <jholland=40akamai.com@dmarc.ietf.org>, "tsvwg@ietf.org" <tsvwg@ietf.org>
References: <202006230427.05N4RCPD013644@gndrsh.dnsmgr.net>
From: Wesley Eddy <wes@mti-systems.com>
Message-ID: <a0d8e8fc-e5ea-64dd-31ae-001bfeb6f38d@mti-systems.com>
Date: Tue, 23 Jun 2020 00:39:18 -0400
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0
MIME-Version: 1.0
In-Reply-To: <202006230427.05N4RCPD013644@gndrsh.dnsmgr.net>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-US
Archived-At: <https://mailarchive.ietf.org/arch/msg/tsvwg/9sVUE-SJ1Whq-FO0HGnghl5x6_4>
Subject: Re: [tsvwg] path forward on L4S issue #16
X-BeenThere: tsvwg@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Transport Area Working Group <tsvwg.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tsvwg>, <mailto:tsvwg-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tsvwg/>
List-Post: <mailto:tsvwg@ietf.org>
List-Help: <mailto:tsvwg-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tsvwg>, <mailto:tsvwg-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 23 Jun 2020 04:39:27 -0000

Hi Rod, I didn't say any of the things you're asking about; only that 
DSCP global traversal does not appear viable to depend on in the near term.


On 6/23/2020 12:27 AM, Rodney W. Grimes wrote:
> Hello Wes,
>
> Excuse me, but L4S itself even defined DSCP as one of the
> alternative mechansims to ECT(1).  Are you saying we should
> remove those alternatives from the draft?
>
> Further on several occasions David Black, and others have asserted that
> DSCP is a viable path forward for L4S.
>
> How are these solutions suddenly not to be included in the considerations
> of what may be a way to address Issue #16?  These are solutions that
> can be used today, though the global traversal is not a requirement
> for them to be used, and they are infact being used to conduct SCE
> experimentation.  I find it unsettling that L4S proponets would not
> consider this as a way to produce data that might influence the WG.
>
> No comments inline,
> Regards,
> Rod
>
>> Hi Rod, I just have a short comment from what I have seen as the WG
>> interests.
>>
>> I have not noticed much interest in DSCP global traversal, especially
>> from the parties that would need to support it.? Since that is also
>> explicitly against the DiffServ architecture that incorporates
>> re-marking, suggesting it is a rather big change to all of how DiffServ
>> has been defined, unless I misunderstand.? I believe any activity or
>> proposals on global DSCP traversal are very interesting and totally fine
>> to discuss, but can't be a gate for L4S.
>>
>>
>> On 6/19/2020 11:14 PM, Rodney W. Grimes wrote:
>>> Jake,
>>> 	Thank you for spending the time to collect this
>>> detailed summary.
>>>
>>> 	I believe you left out: (adding one to your last one and listing)
>>>
>>>    7.  Use a DSCP to seperate the experiment, leaving ECT(1) and CE as
>>>        currently specified in the L4S draft.
>>>
>>>    8.  Use a DSCP to classify the traffic as L4S and leave ECT(1) unused,
>>>        altering CE semantics.
>>>
>>>    9.  Use a DSCP to classify the traffic, and use ECT(1) as a 1/p signal,
>>>        leaving CE semantics in place.
>>>
>>> 10.  Dropping L4S as over promising and short delivering with complexity
>>>        that almost certainly sets it up for a failed deployment.
>>>
>>> Note that in all 4 of these solutions bleaching is unlikely to be
>>> used if there are problems, and the experiment is rather trivial to
>>> terminate if there are problems.  These also keep ECT(1) avaliable
>>> for a future non-experiment version of L4S should the experiment work,
>>> or something else should it fail.  7 to 9 can even be started today
>>> without an IETF consenses and some real operational data created.
>>>
>>> On the side, IMHO, the work going into L4S would be better spent addressing:
>>> a)  DSCP global traversal
>>> b)  ack thinning being underspecified such that it creates protocol
>>>       problems.  Specifically the fact it tosses out changes in reserved
>>>       bits by thinning packets with different bit values.  This was
>>>       identified years ago and left as a problem, it needs cleaned up.
>>> c)  Revision to RFC6040 and other tunnel related drafts to clear
>>>       the issues there.  Again, identified years ago and left to clean
>>>       up.