Re: [Lsr] "OSPFv3 Extensions for SRv6" - draft-li-ospf-ospfv3-srv6-extensions-07 Questions/Comments

"Ketan Talaulikar (ketant)" <ketant@cisco.com> Sun, 17 November 2019 23:24 UTC

Return-Path: <ketant@cisco.com>
X-Original-To: lsr@ietfa.amsl.com
Delivered-To: lsr@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 8F0AC12011E; Sun, 17 Nov 2019 15:24:16 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -14.499
X-Spam-Level:
X-Spam-Status: No, score=-14.499 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_HI=-5, SPF_PASS=-0.001, URIBL_BLOCKED=0.001, USER_IN_DEF_DKIM_WL=-7.5] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=cisco.com header.b=JWooVlj4; dkim=pass (1024-bit key) header.d=cisco.onmicrosoft.com header.b=svfStImj
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 MiViQyGbp0gO; Sun, 17 Nov 2019 15:24:13 -0800 (PST)
Received: from alln-iport-2.cisco.com (alln-iport-2.cisco.com [173.37.142.89]) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 4E5CF120116; Sun, 17 Nov 2019 15:24:13 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=22810; q=dns/txt; s=iport; t=1574033053; x=1575242653; h=from:to:cc:subject:date:message-id:references: in-reply-to:mime-version; bh=lL6Keadwu+Yhttlt3ze2r2LbCs5/a8e0DUEBlEpsiD0=; b=JWooVlj4ZPxg5VRRElaJP2WCEWyGWpFtgIMWw20fXZ6gxr3S139n+jU+ BcBrvjngMVMxsMwsDhQ1LjrBfvGwQkD6RzS8yrKaly7t7ysK5O2oo5Yra l/uqDAOeAwo+GwzizNnoYnzOF1uHBZFZBiNeBkEpud+LEPc/DgmKJtmnR M=;
IronPort-PHdr: =?us-ascii?q?9a23=3AKTJThxOOgCu36/RfbDQl6mtXPHoupqn0MwgJ65?= =?us-ascii?q?Eul7NJdOG58o//OFDEuKQ/l0fHCIPc7f8My/HbtaztQyQh2d6AqzhDFf4ETB?= =?us-ascii?q?oZkYMTlg0kDtSCDBj4IeLjaTASF8VZX1gj9Ha+YgBY?=
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: =?us-ascii?q?A0DaAADD1dFd/5ldJa1lGgEBAQEBAQE?= =?us-ascii?q?BAQMBAQEBEQEBAQICAQEBAYF+gRwvUAVsWCAECyqDaUCDRgOKcYJemACCUgN?= =?us-ascii?q?UCQEBAQwBASUIAgEBhEACF4IMJDgTAgMLAQEEAQEBAgEFBG2FNwyFUQEBAQE?= =?us-ascii?q?DDAYRChMBATcBDwIBBgIRBAEBKwICAjAdCAIEAQ0FCBqDAYF5TQMuAQ6RLJB?= =?us-ascii?q?kAoE4iGB1gTKCfgEBBYR/GIIXAwaBNowVGIFAP4EQR4JMPoJiAQECAYFgJAe?= =?us-ascii?q?CYzKCLJAThUeXZQZoCoIqhxqFJokqgj6HaI4HgWSOSIFBhneRUAIEAgQFAg4?= =?us-ascii?q?BAQWBaSKBWHAVgydQERSRGgwXFYM7hRSFP3QBgSeNSgEB?=
X-IronPort-AV: E=Sophos;i="5.68,318,1569283200"; d="scan'208,217";a="374910986"
Received: from rcdn-core-2.cisco.com ([173.37.93.153]) by alln-iport-2.cisco.com with ESMTP/TLS/DHE-RSA-SEED-SHA; 17 Nov 2019 23:24:11 +0000
Received: from xch-rcd-011.cisco.com (xch-rcd-011.cisco.com [173.37.102.21]) by rcdn-core-2.cisco.com (8.15.2/8.15.2) with ESMTPS id xAHNOBFY028029 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=FAIL); Sun, 17 Nov 2019 23:24:11 GMT
Received: from xhs-aln-002.cisco.com (173.37.135.119) by XCH-RCD-011.cisco.com (173.37.102.21) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Sun, 17 Nov 2019 17:24:10 -0600
Received: from xhs-rcd-002.cisco.com (173.37.227.247) by xhs-aln-002.cisco.com (173.37.135.119) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Sun, 17 Nov 2019 17:24:10 -0600
Received: from NAM01-BN3-obe.outbound.protection.outlook.com (72.163.14.9) by xhs-rcd-002.cisco.com (173.37.227.247) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Sun, 17 Nov 2019 17:24:10 -0600
ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ieb3XlrnQLhtsd7iBdaPY3xo5wWi7VUn2wdPigsvXl2FW5Dxu4skHEFFBSGEB6OUeIXBmJIuICrbCK7a2t7Fe9CsM7Wh4t/D2o+dJrupHFLAc1hXtYH0uSuaMdW2WHjwopdmA8CJmuSX/iGZMZ2wC9BglSzQffi0A0uO3ce23sJxTdKkitl4HkohJjsGQOIzGC+ECw+6Mp13miIOIzRlf/iZ7LGKbgJS725Pr1KkFfzaN2Vnyw0kX2z6QS5uaFYOQ2J2+wvmg7Gc/sebpgD4/pcXK/yBuTA8UrFAyVy9UpHrH3tnD8pbn8Re6WTnKzsT8UzRU7dq90e+igDfRot8eQ==
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=lL6Keadwu+Yhttlt3ze2r2LbCs5/a8e0DUEBlEpsiD0=; b=DrHO/U2DoAro0D1dBs357hQCOT0A509KcT/dpCiew7m/y7smOyWR0fOuZp+TsyBWjfNzniThgM0tLugoFvVu/d6B6JLYCR4j5vlk8zvBDYFkwSUd9f151rH9Euc0pODDd/5g8Gy0DiBui8OL0gZWIRPWjdxNEjf2ts4DplXKvSHd6U4ncqC/ebvhSn+zfwSVwvgvXiy3VKciXPgIvI1twIAnv1kXbzIvuy0kfJO2aWBN8kBKE0OVhJmqV5hH3tJGibN5Qz+zrG/rQ0WU5OITtuJ9RdB0pPrNPQ2ttylomL7aVr5xkeWzDWnqnylig/1ebsjdWW7Ns5beJaiadEzeLg==
ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=cisco.com; dmarc=pass action=none header.from=cisco.com; dkim=pass header.d=cisco.com; arc=none
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cisco.onmicrosoft.com; s=selector2-cisco-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=lL6Keadwu+Yhttlt3ze2r2LbCs5/a8e0DUEBlEpsiD0=; b=svfStImjZ/XP95ynk0BE9PUM3HWw0D6ru8vn8hS6Jfn0IOxZVy589AYjecVFGENmC0I6gGGEGGCl66I8pn8svHTKJEtnHcOBdKO9UMnpyDf4wE1+db9l7wHKOcO1VM2Sso177g1Ycx+8Gh7D9aVF8vD2JZeMtBIFSIYExf4JgqU=
Received: from CY4PR11MB1541.namprd11.prod.outlook.com (10.172.68.150) by CY4PR11MB1365.namprd11.prod.outlook.com (10.169.250.139) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2451.26; Sun, 17 Nov 2019 23:24:09 +0000
Received: from CY4PR11MB1541.namprd11.prod.outlook.com ([fe80::d3a:84a6:be65:e33f]) by CY4PR11MB1541.namprd11.prod.outlook.com ([fe80::d3a:84a6:be65:e33f%11]) with mapi id 15.20.2451.029; Sun, 17 Nov 2019 23:24:09 +0000
From: "Ketan Talaulikar (ketant)" <ketant@cisco.com>
To: "Acee Lindem (acee)" <acee@cisco.com>, "draft-li-ospf-ospfv3-srv6-extensions@ietf.org" <draft-li-ospf-ospfv3-srv6-extensions@ietf.org>
CC: "lsr@ietf.org" <lsr@ietf.org>
Thread-Topic: "OSPFv3 Extensions for SRv6" - draft-li-ospf-ospfv3-srv6-extensions-07 Questions/Comments
Thread-Index: AQHVnZTv18z/fBfHzU6sxa0nMJwCM6eP/fcQ
Date: Sun, 17 Nov 2019 23:24:09 +0000
Message-ID: <CY4PR11MB1541636E83F176D43D10A6C8C1720@CY4PR11MB1541.namprd11.prod.outlook.com>
References: <50EB2052-5917-4DF1-B597-8C384FDECDC9@cisco.com>
In-Reply-To: <50EB2052-5917-4DF1-B597-8C384FDECDC9@cisco.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
authentication-results: spf=none (sender IP is ) smtp.mailfrom=ketant@cisco.com;
x-originating-ip: [2001:420:c0d4:1001::33]
x-ms-publictraffictype: Email
x-ms-office365-filtering-correlation-id: 973b95bb-6074-44ad-d2db-08d76bb53f6d
x-ms-traffictypediagnostic: CY4PR11MB1365:
x-ms-exchange-transport-forked: True
x-microsoft-antispam-prvs: <CY4PR11MB1365F025D6EB98C5B4E930FCC1720@CY4PR11MB1365.namprd11.prod.outlook.com>
x-ms-oob-tlc-oobclassifiers: OLM:9508;
x-forefront-prvs: 02243C58C6
x-forefront-antispam-report: SFV:NSPM; SFS:(10009020)(4636009)(346002)(396003)(366004)(136003)(376002)(39860400002)(189003)(199004)(229853002)(25786009)(33656002)(2501003)(102836004)(4326008)(7696005)(86362001)(450100002)(236005)(76176011)(64756008)(66446008)(9326002)(8676002)(81166006)(81156014)(52536014)(6246003)(8936002)(14444005)(256004)(76116006)(14454004)(99286004)(966005)(11346002)(476003)(486006)(46003)(71190400001)(71200400001)(66556008)(66476007)(790700001)(6116002)(5660300002)(66946007)(186003)(446003)(2906002)(6306002)(54896002)(6436002)(55016002)(110136005)(9686003)(478600001)(316002)(606006)(53546011)(6506007)(7736002)(74316002); DIR:OUT; SFP:1101; SCL:1; SRVR:CY4PR11MB1365; H:CY4PR11MB1541.namprd11.prod.outlook.com; FPR:; SPF:None; LANG:en; PTR:InfoNoRecords; MX:1; A:1;
received-spf: None (protection.outlook.com: cisco.com does not designate permitted sender hosts)
x-ms-exchange-senderadcheck: 1
x-microsoft-antispam: BCL:0;
x-microsoft-antispam-message-info: s2KA6ohus7e0n8E4C2QCAJpJzYmcHu3TX47X2SorwmIN9RpmTTtpMSrsQdx5MHfk88mAOcouHOWVhSNuB2bblgia0bkrk8CuZ2/oeKTzj8ixg5wt89Rsb/zgkz8Yj9i0jTnGh1XVm2Y8tuyR+mrZ3a0A5lQe8lT5GF583HhFAP4suvg/dEvXEd3cNYbvAdFkDYJ4sPaDiBFHRLwRTUssplNkCl8fQIE1GG5YFgVl2kBDBBUZnb5Dd0bgID0DMhJpp+NCRet+2iRcQOPbdGV2EAio0JUeoVIxkWkr9YgyCZUrlpc6i6ujz0EZhoogJF3mfKnoQPdmxBIJOqPgmQd0o1nonPlNpUJYit9GKjBRFV7bbiIMbV0Bj+gZt8vpD0Dj9ZeXAm/PVvHyt+8kX6xqOjX5NCtTtN4BYjDqR+0NeV7IBU13Q2Tlnz86isf6P/LD
Content-Type: multipart/alternative; boundary="_000_CY4PR11MB1541636E83F176D43D10A6C8C1720CY4PR11MB1541namp_"
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: 973b95bb-6074-44ad-d2db-08d76bb53f6d
X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Nov 2019 23:24:09.3109 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 5ae1af62-9505-4097-a69a-c1553ef7840e
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: a/63/SOKt3AH2nCweSSWTSxEADAlJZ3v607XBVG+yWE/qspmx1GeB9TLfO7dfBa4bcFSDwmKQaa4kB2j19EBiw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR11MB1365
X-OriginatorOrg: cisco.com
X-Outbound-SMTP-Client: 173.37.102.21, xch-rcd-011.cisco.com
X-Outbound-Node: rcdn-core-2.cisco.com
Archived-At: <https://mailarchive.ietf.org/arch/msg/lsr/BPRUXSUeFJmXEr4DURYbeLrZJMw>
Subject: Re: [Lsr] "OSPFv3 Extensions for SRv6" - draft-li-ospf-ospfv3-srv6-extensions-07 Questions/Comments
X-BeenThere: lsr@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Link State Routing Working Group <lsr.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/lsr>, <mailto:lsr-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/lsr/>
List-Post: <mailto:lsr@ietf.org>
List-Help: <mailto:lsr-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/lsr>, <mailto:lsr-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sun, 17 Nov 2019 23:24:17 -0000

Hi Acee,

Thanks for your review and comments. Please check inline below.

From: Acee Lindem (acee) <acee@cisco.com>
Sent: 18 November 2019 06:18
To: draft-li-ospf-ospfv3-srv6-extensions@ietf.org
Cc: lsr@ietf.org
Subject: "OSPFv3 Extensions for SRv6" - draft-li-ospf-ospfv3-srv6-extensions-07 Questions/Comments

Hi Authors,
I know you have asked for adoption and I have some comments on the draft. I think these need to be addressed or at least answered prior to any LSR adoption call. In my opinion, this document is not ready.


  1.  Why do you define a separate SRv6 Locator LSA to advertise SRv6 reachability? One of the primary benefits of RFC8362 is to advertise all the information associated with a prefix in one LSA. Now you have negated that benefit by putting this information in a separate LSA.
[KT] We need to define a new LSA since this is not an extension for the normal prefix reachability. For doing FlexAlgo with SRv6, the locators are used for reachability computation within the FlexAlgo. If these were advertised as normal prefix reachability then routers which are not part of the FlexAlgo or even routers not supporting SRv6 would program them. We’ve tried to explain this in https://tools.ietf.org/html/draft-li-ospf-ospfv3-srv6-extensions-07#section-5.

Note that in ISIS, the SRv6 Locators are introduced as a new top-level TLV along side the Prefix Reachability TLV. So what we propose in OSPFv3 is consistent with that model.


  1.  Why do always advertise 128 bit values even when you don’t need it? You should only advertise the part of the Locator or SID required dependent on the LOC:FUNCTION split (padded to a 4 octet boundary). I would expect the SIDs the are Sub-TLVs of the Locator TLV would have that locator in the high-order bit…
[KT] I believe the Locator being a prefix can be advertised only up to the LOC part – similar to how it’s done for IS-IS. The SID is being advertised as a 128-bit value (IPv6 address and not subnet/prefix) and hence we’ve tried to be consistent with the same in OSPFv3 as well.


  1.  Similarly, what is the purpose of the SRv6 SID Structure Sub-TLV? ietf-spring-srv6-network-programming defines the locator to the first N bits and the function to the remaining 128-N bits so I don’t see the need for this TLV. At the very least, there should be text defining how it is used.
[KT] This is consistent with https://tools.ietf.org/html/draft-ietf-spring-srv6-network-programming-05#section-3.1

Also, some editorial comments to make the text consistent with other OSPF documents.


  1.  There is a mixture of US English and UK English of preferred spellings. Please use the US English as the is the style of IETF documents. For example, lose the extra “u” in “behavior”.
  2.  OSPF doesn’t define sub-sub-TLVs, sub-sub-sub-TLVs, or any other alliterative TLSs.  This is an IS-IS artifact. Any TLV that is not a top-level TLV is a Sub-TLV and can be defined at any level of nesting. The GMPLS optical encodings in OSPF are very heavily nested.
  3.  Sub-TLV is capitalized, not “sub-TLVs”.
[KT] Mea culpa … we’ll fix all of these in the next update.

Thanks,
Ketan

Thanks,
Acee