Re: [Isis-wg] Alexey Melnikov's Discuss on draft-ietf-isis-rfc4971bis-03: (with DISCUSS and COMMENT)

"Les Ginsberg (ginsberg)" <ginsberg@cisco.com> Tue, 16 August 2016 16:56 UTC

Return-Path: <ginsberg@cisco.com>
X-Original-To: isis-wg@ietfa.amsl.com
Delivered-To: isis-wg@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 3F77E12D8DE; Tue, 16 Aug 2016 09:56:44 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -15.768
X-Spam-Level:
X-Spam-Status: No, score=-15.768 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, RP_MATCHES_RCVD=-1.247, SPF_PASS=-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
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 09uLOpE1W6hT; Tue, 16 Aug 2016 09:56:42 -0700 (PDT)
Received: from rcdn-iport-8.cisco.com (rcdn-iport-8.cisco.com [173.37.86.79]) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 6433E12D8E6; Tue, 16 Aug 2016 09:56:42 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=4208; q=dns/txt; s=iport; t=1471366602; x=1472576202; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-transfer-encoding:mime-version; bh=Lixdrk3kB/aC2xHe1dnxoHQOfKrH3mBu/qvT81X+2jA=; b=hj0BytzNBTgJR4xRM1T4P2relWWnYG/80HkE00rRuiMZHLAehOQmqciU +5v9QRoydyoKx0ldnpzp5ucWWaIEQqyUaVSF5XrAyofFfLgKa2KWP0yts w4O/EA1j8JQLqoKIDJS/XBQMKd8AlaA8MdcI8c4K0OOkrt1pz1IzilnX4 o=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: =?us-ascii?q?A0DvAgA4RbNX/5xdJa1eg0VWfAe3M4IPg?= =?us-ascii?q?X0mhXcCHIE4OBQCAQEBAQEBAV4nhF4BAQQBIxFFDAQCAQgOAwQBAQMCIwMCAgI?= =?us-ascii?q?wFAEICAIEAQ0FCAGIIAgOrg+QMQEBAQEBAQEBAQEBAQEBAQEBAQEBARyBAYUph?= =?us-ascii?q?E2EEhEBgx2CWgWIKpEXAYYdiHSBcoRciH6MOIN3AR42ghIcF4E1bgGFYDcBfgE?= =?us-ascii?q?BAQ?=
X-IronPort-AV: E=Sophos;i="5.28,529,1464652800"; d="scan'208";a="136476063"
Received: from rcdn-core-5.cisco.com ([173.37.93.156]) by rcdn-iport-8.cisco.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Aug 2016 16:56:38 +0000
Received: from XCH-ALN-003.cisco.com (xch-aln-003.cisco.com [173.36.7.13]) by rcdn-core-5.cisco.com (8.14.5/8.14.5) with ESMTP id u7GGubae009376 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=FAIL); Tue, 16 Aug 2016 16:56:38 GMT
Received: from xch-aln-001.cisco.com (173.36.7.11) by XCH-ALN-003.cisco.com (173.36.7.13) with Microsoft SMTP Server (TLS) id 15.0.1210.3; Tue, 16 Aug 2016 11:56:37 -0500
Received: from xch-aln-001.cisco.com ([173.36.7.11]) by XCH-ALN-001.cisco.com ([173.36.7.11]) with mapi id 15.00.1210.000; Tue, 16 Aug 2016 11:56:37 -0500
From: "Les Ginsberg (ginsberg)" <ginsberg@cisco.com>
To: Alexey Melnikov <aamelnikov@fastmail.fm>, The IESG <iesg@ietf.org>
Thread-Topic: Alexey Melnikov's Discuss on draft-ietf-isis-rfc4971bis-03: (with DISCUSS and COMMENT)
Thread-Index: AQHR99T2FgguQ06+B0ipCPLGFOcdOqBLzKmQ
Date: Tue, 16 Aug 2016 16:56:37 +0000
Message-ID: <16512c4a95214a36972736635f275ba6@XCH-ALN-001.cisco.com>
References: <147136220282.22903.10134856216046001373.idtracker@ietfa.amsl.com>
In-Reply-To: <147136220282.22903.10134856216046001373.idtracker@ietfa.amsl.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-ms-exchange-transport-fromentityheader: Hosted
x-originating-ip: [128.107.151.10]
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
MIME-Version: 1.0
Archived-At: <https://mailarchive.ietf.org/arch/msg/isis-wg/nXg4yDHsxmvD4YiqG0xjEG3mGhc>
Cc: "isis-wg@ietf.org" <isis-wg@ietf.org>, "chopps@chopps.org" <chopps@chopps.org>, "isis-chairs@ietf.org" <isis-chairs@ietf.org>, "draft-ietf-isis-rfc4971bis@ietf.org" <draft-ietf-isis-rfc4971bis@ietf.org>
Subject: Re: [Isis-wg] Alexey Melnikov's Discuss on draft-ietf-isis-rfc4971bis-03: (with DISCUSS and COMMENT)
X-BeenThere: isis-wg@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: IETF IS-IS working group <isis-wg.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/isis-wg>, <mailto:isis-wg-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/isis-wg/>
List-Post: <mailto:isis-wg@ietf.org>
List-Help: <mailto:isis-wg-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/isis-wg>, <mailto:isis-wg-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 16 Aug 2016 16:56:44 -0000

Alexey -

> -----Original Message-----
> From: Alexey Melnikov [mailto:aamelnikov@fastmail.fm]
> Sent: Tuesday, August 16, 2016 8:43 AM
> To: The IESG
> Cc: draft-ietf-isis-rfc4971bis@ietf.org; Christian Hopps; isis-chairs@ietf.org;
> chopps@chopps.org; isis-wg@ietf.org
> Subject: Alexey Melnikov's Discuss on draft-ietf-isis-rfc4971bis-03: (with
> DISCUSS and COMMENT)
> 
> Alexey Melnikov has entered the following ballot position for
> draft-ietf-isis-rfc4971bis-03: Discuss
> 
> When responding, please keep the subject line intact and reply to all email
> addresses included in the To and CC lines. (Feel free to cut this introductory
> paragraph, however.)
> 
> 
> Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
> for more information about IESG DISCUSS and COMMENT positions.
> 
> 
> The document, along with other ballot positions, can be found here:
> https://datatracker.ietf.org/doc/draft-ietf-isis-rfc4971bis/
> 
> 
> 
> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
> 
> I would like to get clarification on the following points before recommending
> approval of this document:
> 
> 1) How do multiple CAPABILITY TLVs from the same source treated, if they
> have the same S and D flags, but different subTLV? Are the cumulative? Or
> this is not allowed?
> I am sorry if I missed where this was described, let me know if I did.

[Les:] Section 2 states:

" The Router CAPABILITY TLV is OPTIONAL.  As specified in Section 3,
   more than one Router CAPABILITY TLV from the same source MAY be
   present."

The only problematic case is when you have two TLVs from the same source which have different settings for the same attribute i.e. same sub-TLV but different values. This case is discussed in detail in Section 3. Different sub-TLVs presents no issue of course.
Note this text is unchanged from the existing RFC.

> 
> 2) In Section 4, 1st sentence: how can this specification have requirements
> on implementation that don't support this extension? If this behaviour is
> already prescribed by another specification, then you should not use RFC
> 2118 keyword and you should reference the relevant specification.
> 

[Les:] Ignoring TLVs/sub-TLVs that are not understood is fundamental to the IS-IS protocol and defined in the base spec ISO 10589 (which is referenced). Repeating this is strictly speaking unnecessary - but was done in the original RFC as a point of emphasis.

> 
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
> 
> Should subTLVs have an IANA registry? Or is there an existing one already?
> 

[Les:] http://www.iana.org/assignments/isis-tlv-codepoints/isis-tlv-codepoints.xhtml#isis-tlv-codepoints-242
It has already been noted that the registry should be updated to point to the new RFC once it is published.

   Les