[tsvwg] L4S DSCP (was: L4S drafts: Next Steps)

"Black, David" <David.Black@dell.com> Mon, 22 March 2021 19:31 UTC

Return-Path: <David.Black@dell.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 BEBEA3A0CF1 for <tsvwg@ietfa.amsl.com>; Mon, 22 Mar 2021 12:31:00 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.45
X-Spam-Level:
X-Spam-Status: No, score=-0.45 tagged_above=-999 required=5 tests=[DKIMWL_WL_HIGH=-0.251, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=unavailable autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=dell.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 GTQhaelW5dxj for <tsvwg@ietfa.amsl.com>; Mon, 22 Mar 2021 12:30:55 -0700 (PDT)
Received: from mx0b-00154904.pphosted.com (mx0b-00154904.pphosted.com [148.163.137.20]) (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 A227B3A0C9A for <tsvwg@ietf.org>; Mon, 22 Mar 2021 12:30:49 -0700 (PDT)
Received: from pps.filterd (m0170396.ppops.net [127.0.0.1]) by mx0b-00154904.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 12MJQfsC008121; Mon, 22 Mar 2021 15:30:46 -0400
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dell.com; h=from : to : cc : subject : date : message-id : content-type : content-transfer-encoding : mime-version; s=smtpout1; bh=6vsLdeW1WXfRkqmgm/jzqAV+MG4vV09fP4GamhOaFBc=; b=noIDBqmLy8jCWyzid7HjAsxEfls3N2eY11jl94lZxEsoi4+7HX4IFGzucqHRGSYmMTOM /GG7TA2TIyTvKYUg73qXPcRe4FzD6dxuifr+jn8AraTUYMlFWraXJw95aOZMiKHAza5k VHEjr45k6YcfwVcHdlf2OXsrj+ll7ivc9eSRMZT1uL1oYiI8H7FgRvgDPvqWx5BslVb3 CV/HOJIQAC6QtYMzX0DsL+SP+ztkNfX/TyU+aL9MzGO2qDZDZUvqfK/hIQ5uxDd5ai6P 1+teRfMnNi2sTrd8QxAtMY92YwbJyg35F+PUVAwqRLNS55WZww53/2vRRXR4HBZTuxRa Ww==
Received: from mx0a-00154901.pphosted.com (mx0a-00154901.pphosted.com [67.231.149.39]) by mx0b-00154904.pphosted.com with ESMTP id 37dmh2nj3t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 22 Mar 2021 15:30:46 -0400
Received: from pps.filterd (m0090351.ppops.net [127.0.0.1]) by mx0b-00154901.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 12MJUEbq082727; Mon, 22 Mar 2021 15:30:45 -0400
Received: from nam11-dm6-obe.outbound.protection.outlook.com (mail-dm6nam11lp2173.outbound.protection.outlook.com [104.47.57.173]) by mx0b-00154901.pphosted.com with ESMTP id 37dx9f49q2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 22 Mar 2021 15:30:45 -0400
ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=S+J0Euem9DV/ximvcg2OV5M/igRU2i3uXGPGaEncoo/TVQipL7M3bwbQbDtBfZ2v9IGmxchmT26VX2Yu/7ZPupow4LnDPJsFqvuFZRBURKxEdoZUBzbvGSBClyIeIesTadhOIppKxUbUNlY/ieqMm4n/SPWFIGpeYsSv6QvZSAaRzqVZdcwgIgShsN2i6IqRlKcq4Pa0SUN7nIDD3kapFHgTqlycY1SfntbYm2C/RPfS3SrBm/147QQIL19I9rJpb4RMeVo/QRpVA9zyCjDuIt7mtPMhgHCSs3QFBMxu5P/ZdzH/X6VYkujoBWZ8FUiDNioDsyvF3QgB9eC5qw7RUQ==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=6vsLdeW1WXfRkqmgm/jzqAV+MG4vV09fP4GamhOaFBc=; b=GToRC0mkdv4j3pYoatEQv6ReLf5CEh6avYVK7uizGgQRcK8wv6GttXy5GWRcGTDacTQujbL/pd1H6GfUQOKOce5lbxkykMqSo5LJE6WA6rzRRpK3qk1yZntpaKJlyVMXkj8aaP1gN2APVH1YChXgT43xiiM+VxPlNOIMlNdLTqXsoYtnddpxWhkRgfGKjAA6ftFtbjQUJy+SQ2zzF83zksFtgNZXYG3ig5KCnT7zMlJMNHSC6clh/uQItMWW4Y99BFDNfRh9mXfa2JXFDIG9FH9vTtBNiXopTzD5+VLWG09yKzziTsKO4kfZtl0anuodxboYlZE/gFgMKopSJ+nR/A==
ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=dell.com; dmarc=pass action=none header.from=dell.com; dkim=pass header.d=dell.com; arc=none
Received: from MN2PR19MB4045.namprd19.prod.outlook.com (2603:10b6:208:1e4::9) by MN2PR19MB4109.namprd19.prod.outlook.com (2603:10b6:208:1eb::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3955.23; Mon, 22 Mar 2021 19:30:43 +0000
Received: from MN2PR19MB4045.namprd19.prod.outlook.com ([fe80::b1f3:f51d:c01c:2feb]) by MN2PR19MB4045.namprd19.prod.outlook.com ([fe80::b1f3:f51d:c01c:2feb%6]) with mapi id 15.20.3955.027; Mon, 22 Mar 2021 19:30:43 +0000
From: "Black, David" <David.Black@dell.com>
To: Pete Heist <pete@heistp.net>, "Livingood, Jason" <Jason_Livingood=40comcast.com@dmarc.ietf.org>
CC: "tsvwg@ietf.org" <tsvwg@ietf.org>, "Black, David" <David.Black@dell.com>
Thread-Topic: L4S DSCP (was: L4S drafts: Next Steps)
Thread-Index: AdcfUdg330SgU1t/Rc2OwNBrVFfTig==
Date: Mon, 22 Mar 2021 19:30:43 +0000
Message-ID: <MN2PR19MB404527384A1B1DD9CFC2A3D983659@MN2PR19MB4045.namprd19.prod.outlook.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
msip_labels: MSIP_Label_17cb76b2-10b8-4fe1-93d4-2202842406cd_Enabled=True; MSIP_Label_17cb76b2-10b8-4fe1-93d4-2202842406cd_SiteId=945c199a-83a2-4e80-9f8c-5a91be5752dd; MSIP_Label_17cb76b2-10b8-4fe1-93d4-2202842406cd_Owner=david.black@emc.com; MSIP_Label_17cb76b2-10b8-4fe1-93d4-2202842406cd_SetDate=2021-03-22T19:13:10.6003293Z; MSIP_Label_17cb76b2-10b8-4fe1-93d4-2202842406cd_Name=External Public; MSIP_Label_17cb76b2-10b8-4fe1-93d4-2202842406cd_Application=Microsoft Azure Information Protection; MSIP_Label_17cb76b2-10b8-4fe1-93d4-2202842406cd_ActionId=fe60a657-74c3-4588-9909-b233207917dc; MSIP_Label_17cb76b2-10b8-4fe1-93d4-2202842406cd_Extended_MSFT_Method=Manual
authentication-results: heistp.net; dkim=none (message not signed) header.d=none;heistp.net; dmarc=none action=none header.from=dell.com;
x-originating-ip: [72.74.71.221]
x-ms-publictraffictype: Email
x-ms-office365-filtering-correlation-id: 9f6732c3-0499-4bb7-e9e6-08d8ed68fc05
x-ms-traffictypediagnostic: MN2PR19MB4109:
x-ms-exchange-transport-forked: True
x-microsoft-antispam-prvs: <MN2PR19MB41094F751692C902487DD74D83659@MN2PR19MB4109.namprd19.prod.outlook.com>
x-exotenant: 2khUwGVqB6N9v58KS13ncyUmMJd8q4
x-ms-oob-tlc-oobclassifiers: OLM:10000;
x-ms-exchange-senderadcheck: 1
x-microsoft-antispam: BCL:0;
x-microsoft-antispam-message-info: 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
x-forefront-antispam-report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:MN2PR19MB4045.namprd19.prod.outlook.com; PTR:; CAT:NONE; SFS:(4636009)(346002)(396003)(39860400002)(376002)(136003)(366004)(107886003)(86362001)(478600001)(83380400001)(33656002)(54906003)(110136005)(52536014)(71200400001)(66574015)(76116006)(9686003)(4326008)(66476007)(66556008)(64756008)(66446008)(66946007)(55016002)(5660300002)(2906002)(7696005)(8676002)(966005)(53546011)(8936002)(186003)(6506007)(38100700001)(26005)(786003)(316002); DIR:OUT; SFP:1101;
x-ms-exchange-antispam-messagedata: 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
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
MIME-Version: 1.0
X-OriginatorOrg: Dell.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: MN2PR19MB4045.namprd19.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 9f6732c3-0499-4bb7-e9e6-08d8ed68fc05
X-MS-Exchange-CrossTenant-originalarrivaltime: 22 Mar 2021 19:30:43.3015 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 945c199a-83a2-4e80-9f8c-5a91be5752dd
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: sw3TFEXB4jWjz2PTgehl5/NLhtvkgD3sbK7BmiGlq5REcv1K69rS2R0yftTsMlZHKeNE7b2rnv/wiHomYnR3Ew==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR19MB4109
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369, 18.0.761 definitions=2021-03-22_11:2021-03-22, 2021-03-22 signatures=0
X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 mlxscore=0 lowpriorityscore=0 adultscore=0 impostorscore=0 malwarescore=0 phishscore=0 suspectscore=0 bulkscore=0 mlxlogscore=999 spamscore=0 clxscore=1011 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2103220142
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 phishscore=0 suspectscore=0 adultscore=0 malwarescore=0 mlxscore=0 mlxlogscore=999 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2103220142
Archived-At: <https://mailarchive.ietf.org/arch/msg/tsvwg/oRi3Mqv6vrKrj5ZKE-_dywQaYuU>
Subject: [tsvwg] L4S DSCP (was: L4S drafts: Next Steps)
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: Mon, 22 Mar 2021 19:31:07 -0000

Following up on Pete's comment:

> Along these lines, there is nothing stopping anyone from using DSCP (as
> an appropriate risk control within participating ASs), to perform
> experiments to reproduce issues that can be demonstrated in the lab.

That is a commendable approach, particularly as it is effectively recommended by RFC 4774 (Specifying Alternate Semantics for the Explicit Congestion Notification (ECN) Field) - see Section 3 [1], and take note that RFC 4774 is a BCP (Best Current Practice) whose author was the late Sally Floyd.  It may be time for the WG to reconsider the L4S approach of using alternate ECN semantics without qualification by DSCP, at least to run experiments on actual networks.

My 0.02 is that an Experimental RFC that used a DSCP to signal the L4S ECN semantics (in participating networks) could have been published at least 2 years ago.
 
Thanks, --David (as a TSVWG co-chair, but not claiming to speak for other co-chairs)
[1] https://datatracker.ietf.org/doc/html/rfc4774#section-3

-----Original Message-----
From: tsvwg <tsvwg-bounces@ietf.org> On Behalf Of Pete Heist
Sent: Monday, March 22, 2021 4:04 AM
To: Livingood, Jason
Cc: tsvwg@ietf.org
Subject: Re: [tsvwg] L4S drafts: Next Steps


[EXTERNAL EMAIL] 

Hi Jason, one comment below...

On Sat, 2021-03-20 at 15:08 +0000, Livingood, Jason wrote:
> > The lab studies have shown
> 
> IMO the challenge with lab studies is that there are a lot of variables
> that are artificial and/or the test environment or test traffic does
> not fully reflect reality (production). 10 or 15 years ago I would have
> been very focused on extensive QA testing and an elaborate lab test
> environment. These days its more how to do controlled testing directly
> in the production network, with a controlled/minimized blast radius in
> case of problems, easy/quick rollback, rapid code/config iteration.
> 
> > far from a promising system that might be ready for a field trial,
> > one that shows worrying failure modes that primarily affect innocent
> > bystanders.
> >  What we're asking for is a system that at least behaves reasonably
> > under lab conditions, chosen to represent realistic challenge
> > scenarios likely to occur in the real world.  Only then can we have
> > any confidence that L4S will not cause problems anywhere and
> > everywhere that it is deployed.
> 
> Only one way to find out - test it in a real production experiment with
> appropriate risk controls.

Along these lines, there is nothing stopping anyone from using DSCP (as
an appropriate risk control within participating ASs), to perform
experiments to reproduce issues that can be demonstrated in the lab.
Here are a few: https://github.com/heistp/l4s-tests/

It would be nice if someone took the time to set up some production
gear with fq_codel built into it, like routers and/or WiFi access
points, and test various kinds of real-world traffic, through tunnels
and not. One could combine traffic to L4S servers within the
experimental network, along with conventional traffic to anywhere on
the Internet. That seems like a useful step before starting an
Internet-wide experiment. Perhaps even better would be to fix what
safety issues are known so that they can't occur in the first place.

Regards,
Pete

>  The status quo seems to suggest years more debate without (IMO)
> sufficient data. An alternative is a controlled production experiment,
> appropriately risk-managed, between willing participants. I see no
> downside to allowing that to occur via experimental RFC. We're setting
> the bar at the proposed standard or standard level, which I think is
> incorrect. I would say instead enable the experiment to accelerate the
> learning & improvement & drive data-driven decisions.
> 
> Jason
>