Re: [Lsr] Benjamin Kaduk's Discuss on draft-ietf-isis-mpls-elc-12: (with DISCUSS and COMMENT)

"Acee Lindem (acee)" <acee@cisco.com> Tue, 26 May 2020 13:58 UTC

Return-Path: <acee@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 C46D83A0F7D; Tue, 26 May 2020 06:58:36 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -9.598
X-Spam-Level:
X-Spam-Status: No, score=-9.598 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, 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=N5BOlIS6; dkim=pass (1024-bit key) header.d=cisco.onmicrosoft.com header.b=Hssc0Stg
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 DFxmfJs-hNN4; Tue, 26 May 2020 06:58:35 -0700 (PDT)
Received: from rcdn-iport-9.cisco.com (rcdn-iport-9.cisco.com [173.37.86.80]) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id A17453A0F6C; Tue, 26 May 2020 06:58:34 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=7480; q=dns/txt; s=iport; t=1590501514; x=1591711114; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-id:content-transfer-encoding: mime-version; bh=/4b1sWf6hBKpjWQUINoBws8Hc4x5Xpth4iMgI5T2ySU=; b=N5BOlIS6jdATRiU8LA2kavS4z83wIbnE5R+xdVvrqOwpAGc1b9tfRM+U tl75SATF+MiEj1eTaZe35GBDH6wmpr83XTu5e7sTI1vrS4MNzHaM4665L dx4IB7oRaOCo5ITR7fAVN0Qvn0KhraOXnCC8TA8/TkYF2/mqY6uGDqDq2 E=;
IronPort-PHdr: =?us-ascii?q?9a23=3A0YhxixcHr9LPS5hy+s8Lg5uPlGMj4e+mNxMJ6p?= =?us-ascii?q?chl7NFe7ii+JKnJkHE+PFxlwaQAdfQ6ulPjKzdtKWzEWAD4JPUtncEfdQMUh?= =?us-ascii?q?IekswZkkQmB9LNEkz0KvPmLklYVMRPXVNo5Te3ZE5SHsutbFzJqXr05jkXSV?= =?us-ascii?q?3zMANvLbHzHYjfx828y+G1/cjVZANFzDqwaL9/NlO4twLU48IXmoBlbK02z0?= =?us-ascii?q?jE?=
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: =?us-ascii?q?A0DgAQD6H81e/4UNJK1mDg0BAQEBAQE?= =?us-ascii?q?BAQUBAQESAQEBAwMBAQFAgUeBVFEHgUcvLAqEG4NGA41CiXqOQoFCgRADVQs?= =?us-ascii?q?BAQEMAQEtAgQBAYREAheBeCQ4EwIDAQELAQEFAQEBAgEFBG2FVgyFcgEBAQE?= =?us-ascii?q?CARIREQwBATcBDwIBCBgCAiYCAgIfERUQAgQBDQUigwSCTAMOIAGiIAKBOYh?= =?us-ascii?q?hdoEygwEBAQWFLA0Lgg4JgQ4qgmSJYBqCAIERJxyCTT6CHoF6AQESASEXgn0?= =?us-ascii?q?zgi2PCoJcoHlKCoJUjjeFSYRcHYJjiQKSHZBOjDqRKAIEAgQFAg4BAQWBaSJ?= =?us-ascii?q?mcHAVZQGCPlAYDZBAOIM6ihg+dDcCBgEHAQEDCXyLSQGBDwEB?=
X-IronPort-AV: E=Sophos;i="5.73,437,1583193600"; d="scan'208";a="683119624"
Received: from alln-core-11.cisco.com ([173.36.13.133]) by rcdn-iport-9.cisco.com with ESMTP/TLS/DHE-RSA-SEED-SHA; 26 May 2020 13:58:33 +0000
Received: from XCH-RCD-002.cisco.com (xch-rcd-002.cisco.com [173.37.102.12]) by alln-core-11.cisco.com (8.15.2/8.15.2) with ESMTPS id 04QDwXL4005986 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=FAIL); Tue, 26 May 2020 13:58:33 GMT
Received: from xhs-aln-003.cisco.com (173.37.135.120) by XCH-RCD-002.cisco.com (173.37.102.12) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 26 May 2020 08:58:33 -0500
Received: from xhs-rtp-001.cisco.com (64.101.210.228) by xhs-aln-003.cisco.com (173.37.135.120) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 26 May 2020 08:58:32 -0500
Received: from NAM12-MW2-obe.outbound.protection.outlook.com (64.101.32.56) by xhs-rtp-001.cisco.com (64.101.210.228) with Microsoft SMTP Server (TLS) id 15.0.1497.2 via Frontend Transport; Tue, 26 May 2020 09:58:29 -0400
ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=G7v3AHvHR7JmnUHekFc3M+Ic19nSXeEJa2uOi4eVSXbIi+NNK4EZUb2ObJTRHR6jRi4E1zlv1rCtnNy1QsQTJ2kCJrbMNw3CMUqCy0mLr2AG2OUymvjTbcWoqBOGEC/YApFmxMH+fI3kmtdPagdQ+j1+J+1fAAYdgH0nL/kGMm4VemnPDE2uutOFIPF8x1IfiGiT+Eg8ExgP9O04UkyO7bC3TGzr6INDdRjLsfZLmeRMXli36HdIzZz3GPo7qBdK6a1fy3lTN5m49c9ZBIxZr23KbtC3KlqIf0fpdN3KCc0Ww/VhzBERbNYdIBiG0jI7nyKU2VT2GIrhRJHr5QuNtQ==
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=/4b1sWf6hBKpjWQUINoBws8Hc4x5Xpth4iMgI5T2ySU=; b=NC7LW0KIABwt4hIhS3fTVOKDWSHjfHev4jZCBkFLOJ2zkbDZo44cxxSgDTtEdXcRSXPa6hGvyuKZmxlIQ+BKiv3jkGxeGru1SvdHYNDStw4wSyDLLwBnSGs0drs1up+VzGxAuEWm3zWxtSy6PLv43E0x2UMqRhh2wM3dXlwmWns59td+oELTFzmhNTCQb+K/kLL9XEUa3tI2QtsTeIMViTnxG1nJgWz5oSXiIyUGn6QwgUVD3SbD4nRvG+fYUe/oA6bqb4LHC2+Z+5v4jQcGGTPbyuz5DwX23h0yKXgEwgOPh1IPbUwrcp324o7ib6o0wKcjD5UnlDhBVuQ+2WzvyA==
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=/4b1sWf6hBKpjWQUINoBws8Hc4x5Xpth4iMgI5T2ySU=; b=Hssc0StgrHkQ5AKJWOjvrDQyb7EqTmSDVZWurO6lbPvmcrtd93TydI0XGfyE3v5trpSK0gaQ8Xtgh2C/8MZX51P6tbjc2Qj41CC7USFLozRQJsWExgNDrcI+ykjYeL+0AHng4/YP9ubyWpfI3V+lpo6pJY+mOJ9HhPDyT1pXuIY=
Received: from BYAPR11MB2887.namprd11.prod.outlook.com (2603:10b6:a03:89::27) by BYAPR11MB2663.namprd11.prod.outlook.com (2603:10b6:a02:ca::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3045.17; Tue, 26 May 2020 13:58:29 +0000
Received: from BYAPR11MB2887.namprd11.prod.outlook.com ([fe80::4950:e26c:503f:768e]) by BYAPR11MB2887.namprd11.prod.outlook.com ([fe80::4950:e26c:503f:768e%6]) with mapi id 15.20.3021.027; Tue, 26 May 2020 13:58:29 +0000
From: "Acee Lindem (acee)" <acee@cisco.com>
To: "Peter Psenak (ppsenak)" <ppsenak@cisco.com>, Alvaro Retana <aretana.ietf@gmail.com>, Benjamin Kaduk <kaduk@mit.edu>
CC: "draft-ietf-isis-mpls-elc@ietf.org" <draft-ietf-isis-mpls-elc@ietf.org>, The IESG <iesg@ietf.org>, "lsr-chairs@ietf.org" <lsr-chairs@ietf.org>, "lsr@ietf.org" <lsr@ietf.org>
Thread-Topic: Benjamin Kaduk's Discuss on draft-ietf-isis-mpls-elc-12: (with DISCUSS and COMMENT)
Thread-Index: AQHWLi8YMiDtiOiXz0umkwYeF81nrKiyUmOAgACgLQCAAURHAIAF0RUAgABMVwD//9fHAA==
Date: Tue, 26 May 2020 13:58:28 +0000
Message-ID: <293409B4-19E6-486B-BCE5-B9B0C58F37BF@cisco.com>
References: <158992828112.6026.1646593855480055081@ietfa.amsl.com> <1242ad52-bb48-8526-b65b-d413e0cd9e25@cisco.com> <20200521193856.GJ58497@kduck.mit.edu> <CAMMESsxo56ZK+DKBMkKvFcXf+1GFPF+wDtRCW=+md8WCoKODxw@mail.gmail.com> <1852869A-2678-4AA7-AEB9-F7A3014A7191@cisco.com> <ed4caa6d-a47c-d550-8a5e-aee4937b5a3a@cisco.com>
In-Reply-To: <ed4caa6d-a47c-d550-8a5e-aee4937b5a3a@cisco.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
user-agent: Microsoft-MacOutlook/16.37.20051002
authentication-results: cisco.com; dkim=none (message not signed) header.d=none;cisco.com; dmarc=none action=none header.from=cisco.com;
x-originating-ip: [136.56.133.70]
x-ms-publictraffictype: Email
x-ms-office365-filtering-correlation-id: 05466f02-ef29-4c10-e7bf-08d8017cde4c
x-ms-traffictypediagnostic: BYAPR11MB2663:
x-ms-exchange-transport-forked: True
x-microsoft-antispam-prvs: <BYAPR11MB2663293CB6AA67F9926BC178C2B00@BYAPR11MB2663.namprd11.prod.outlook.com>
x-ms-oob-tlc-oobclassifiers: OLM:10000;
x-forefront-prvs: 041517DFAB
x-ms-exchange-senderadcheck: 1
x-microsoft-antispam: BCL:0;
x-microsoft-antispam-message-info: 2yZLW3dhjn9UaVvXNh6mwwXFT0oKXbYP5l+vIdvL9YaU/RBW19Vsvgt+tro5hYG9Gvdt2HpNRbm8dxTWl5Q04nPD1SVjgIGXb/yf3/ztJsaYGEKGzKXjks8B1c3MReFfvzpi7Qsrw+RFxZabQgx9bxNwtkn2zg0Qg4608JZekLzWncNuCPi7QN/jAPJYNHLXEQUtlhfPat3GKWbbC70yrGauWyIyyqugJI/SkW89rdZqW4qqGKYhP3XMCD4icLoad3Pw5oe1i54ZJFYNt2C0p3DdwbDB1BL3L2xdBOStTemkInpHm6kF5NYHWYlCMRnnOXVGd2jhybWoopYTiW5FOg==
x-forefront-antispam-report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:BYAPR11MB2887.namprd11.prod.outlook.com; PTR:; CAT:NONE; SFTY:; SFS:(4636009)(376002)(136003)(39860400002)(396003)(346002)(366004)(91956017)(76116006)(64756008)(66446008)(66476007)(66556008)(53546011)(2616005)(6506007)(110136005)(186003)(54906003)(26005)(5660300002)(8676002)(4326008)(33656002)(478600001)(66946007)(6512007)(6486002)(8936002)(2906002)(86362001)(71200400001)(316002)(36756003)(66574014); DIR:OUT; SFP:1101;
x-ms-exchange-antispam-messagedata: JvfR7M7L9SizP3p/M7lhW+ICAS8s5Lrb4Xdv7+Cd+7Zepa3ETamPbZHhz0tWzQhHBD9dOlQAPgleJXTLveoJ0M3LBHFvohnBy2GAbjuGRkWBgJTDMOK91gyLlV+RBoDNs7KcI8MIbw6WDB6/1Si1jLPCNHDgXZ2BDChNBlYMXMVlEPLHHCRNSOywt75ew0p/ajSF1fPzgWytjQQNji5qcB6ZFJeSVcWqmI32jcrY/QColgIXzul3gKU9D7/tYU/RXwGHOUhFkNIsdv0rQaM8NRyKRvvHbuq7MQ2hobBGawpC3KMEkMP9TIRv91ptS94uS+vtMJYtUgRGKd+YNAJJBglFhqFx5rSDxTznCh1RpzTgoEzR/Yl9rcgwvvxCzJ+F1xm67LHRUIgHPMFnRvw22Wch/wU6NOBKvUlTDxRSRPxGh4gqxeN2o8HhVGHtvGxKQeIVntON1QRuJl1mljW2YcjQECOkf2UjXMkv+SCo1yU=
Content-Type: text/plain; charset="utf-8"
Content-ID: <E6666F77F54D3B42B0260B7B185CE793@namprd11.prod.outlook.com>
Content-Transfer-Encoding: base64
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: 05466f02-ef29-4c10-e7bf-08d8017cde4c
X-MS-Exchange-CrossTenant-originalarrivaltime: 26 May 2020 13:58:28.8340 (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: 6L7bYjvs88ZQfYYgbctRkIFQoSecups1g2DGMkxogkqaptMwxIe873oS1Au/8JoJ
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR11MB2663
X-OriginatorOrg: cisco.com
X-Outbound-SMTP-Client: 173.37.102.12, xch-rcd-002.cisco.com
X-Outbound-Node: alln-core-11.cisco.com
Archived-At: <https://mailarchive.ietf.org/arch/msg/lsr/lfRIJnCbUVvUIs0wX7PmmslyTM0>
Subject: Re: [Lsr] Benjamin Kaduk's Discuss on draft-ietf-isis-mpls-elc-12: (with DISCUSS and COMMENT)
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: Tue, 26 May 2020 13:58:38 -0000

Hi Peter, 

On 5/26/20, 8:22 AM, "Peter Psenak" <ppsenak@cisco.com> wrote:

    Hi Acee,

    have you looked at the texts that I suggested in my response to Alvaro 
    earlier today?

I found it - let me reply to that Email.

Thanks,
Acee


    Please see inline:

    On 26/05/2020 13:49, Acee Lindem (acee) wrote:
    > Hi Alvaro,
    > 
    > See inline.
    > 
    > On 5/22/20, 10:59 AM, "Alvaro Retana" <aretana.ietf@gmail.com> wrote:
    > 
    >      On May 21, 2020 at 3:39:03 PM, Benjamin Kaduk wrote:
    > 
    > 
    >      Peter:
    > 
    >      Hi!
    > 
    > 
    >      > With respect to Alvaro's clarification, your answer for (1) makes sense;
    >      > thanks! I think Alvaro has offered to help work out what (if any)
    >      > additional text we might want to be sure that the answer to (2) is clear in
    >      > the document.
    > 
    >      I think that #1 is where some clarification could be useful. :-)
    > 
    > 
    >      I'm including both ISIS and OSPF suggestions below to consolidate the
    >      discussion.
    > 
    > 
    >      ...
    >      > > My interpretation of Ben's question is two-fold:
    >      > >
    >      > > (1) Would ISIS routers normally propagate the information to a
    >      > > different level? The ELC is a new prefix attribute flag -- are prefix
    >      > > attributes always propagated (unchanged) to other levels? If so, then
    >      > > the requirement (MUST) is not needed. My reading of rfc7794 is that
    >      > > the propagation is optional...
    >      >
    >      > depends on the attribute or a bit. Some are propagated some are not.
    >      > That's why we are saying this one MUST be preserved.
    > 
    >      Right.
    > 
    >      For ISIS I think the current text is in line with the specification of
    >      the other bits in rfc7794.  No changes are needed.
    > 
    >      If anything, you may want to change the order of this sentence to
    >      address Ben's comment:
    > 
    >      OLD>
    >         When a router propagates a prefix between ISIS levels ([RFC5302], it
    >         MUST preserve the ELC signaling for this prefix.
    > 
    >      NEW>
    >         The ELC signaling MUST be preserved when a router propagates a prefix
    >         between ISIS levels ([RFC5302]).
    > 
    >      [Similar for OSPF.]
    > 
    > 
    > 
    >      I think that for OSPF it is not that simple...
    > 
    >      For OSPFv2: rfc7684 says that the "scope of the OSPFv2 Extended Prefix
    >      Opaque LSA depends on the scope of the advertised prefixes", which I
    >      assume means that for intra-area prefixes the scope will be
    >      area-local...so the ABR wouldn't simply propagate it; it would have to
    >      originate a new LSA.
    > 
    > I agree with the changes but have suggested alternate text.
    > 
    >      Suggestion (Add to 3.1)>
    >         When an OSPFv2 Area Border Router (ABR) distributes information between
    >         connected areas it SHOULD originate an OSPFv2 Extended Prefix Opaque LSA
    >         [RFC7684] including the received ELC setting.  If the received information
    >         is included in an LSA with an AS-wide scope, then the new LSA is not needed.

    when would ABR do inter area propagation of what is advertised in AS 
    scope LSA? I can not think of such a case.

    thanks,
    Peter


    > 
    > I'd suggest:
    > 
    >        When an OSPFv2 Area Border Router (ABR) advertises prefix information between
    >        areas and ELC information is was advertised for the prefix in the source area, the
    >        ABR SHOULD originate an OSPFv2 Extended Prefix Opaque LSA [RFC7684] propagating
    >        the prefix's source area setting. If the ELC setting, is also advertised in an OSPFv2
    >        Extended Prefix Opaque LSA with AS-wide scope, the additional LSA origination
    >        Is not needed.
    > 
    > 
    >      For OSPFv3: The PrefixOptions are *in* the LSA, but I couldn't find
    >      anything in rfc5340 saying that the received values should be copied
    >      into the Inter-Area-Prefix-LSA (nor that they should not).
    > 
    >      Suggestion (Add to 3.2)>
    >         When an OSPFv3 Area Border Router (ABR) distributes information between
    >         connected areas, the setting of the ELC Flag in the Inter-Area-Prefix-LSA
    >         MUST be the same as the received value.
    > 
    > I'd suggest:
    >        
    >        When an OSPFv3 Area Border Router (ABR) advertises information between
    >        areas, the setting of the ELC flag in the Inter-area-prefix-LSA MUST be the
    >        propagated unchanged.
    > 
    > Thanks,
    > Acee
    > 
    > 
    > 
    > 
    >      > > (2) If the propagation is not automatic, and the L1L2 router doesn't
    >      > > support this specification, then what are the drawbacks/failure
    >      > > scenarios? IOW, for multi-level operation is it a requirement that
    >      > > the L1L2 support this specification?
    >      >
    >      > drawback are identical to what is mentioned in the Security
    >      > Considerations section.
    > 
    >      I think that text is ok.
    > 
    > 
    >      Thanks!
    > 
    >      Alvaro.
    > 
    > 
    >