Re: [OSPF] More Comments on OSPF S-BFD Discriminator

"Les Ginsberg (ginsberg)" <ginsberg@cisco.com> Mon, 09 November 2015 23:16 UTC

Return-Path: <ginsberg@cisco.com>
X-Original-To: ospf@ietfa.amsl.com
Delivered-To: ospf@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5E7C01AC3E4; Mon, 9 Nov 2015 15:16:41 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -14.51
X-Spam-Level:
X-Spam-Status: No, score=-14.51 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, T_RP_MATCHES_RCVD=-0.01, USER_IN_DEF_DKIM_WL=-7.5] autolearn=ham
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 Ib7w57StWn70; Mon, 9 Nov 2015 15:16:39 -0800 (PST)
Received: from alln-iport-4.cisco.com (alln-iport-4.cisco.com [173.37.142.91]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id E897A1AC3E7; Mon, 9 Nov 2015 15:16:38 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=23322; q=dns/txt; s=iport; t=1447110999; x=1448320599; h=from:to:cc:subject:date:message-id:references: in-reply-to:mime-version; bh=ghqOTa0WujwoH9GHWGiptXaVNoAQcFxWSeJkvsmCSmM=; b=VCOL0pW9PStUlKxFD14SopMD4Wpg0j8y35zHwcly5OrmubO9VjbYBLcI feTG8EoMqMrS/USSNpRcDJ+X5wkdK9ul/C8j1j1xromzonfgsX7wqbMng YcymeWRWGHQ0xIelM4sNo/hDZaqDoXP1Cs3Uu6qcQxplx45J+eIXKlc2l A=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: A0D3AQALKUFW/5NdJa1egm5NU28GvjkBDYFjFwEJhW8CHIElOBQBAQEBAQEBgQqENQEBAQQBAQEgCkELEAIBCBEDAQEBKAMCAgIfBgsUCQgCBAENBQiIEQMSDbELjBINhEkBAQEBAQEBAQEBAQEBAQEBAQEBAQEUBIZUhH6CU4IoDQmCZIFEBZJng2EBizGBboFihECNVoEBg2GDcQEfAQFChARyhF+BBwEBAQ
X-IronPort-AV: E=Sophos;i="5.20,267,1444694400"; d="scan'208,217";a="205954046"
Received: from rcdn-core-11.cisco.com ([173.37.93.147]) by alln-iport-4.cisco.com with ESMTP; 09 Nov 2015 23:16:37 +0000
Received: from XCH-ALN-012.cisco.com (xch-aln-012.cisco.com [173.36.7.22]) by rcdn-core-11.cisco.com (8.14.5/8.14.5) with ESMTP id tA9NGaBE016235 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=FAIL); Mon, 9 Nov 2015 23:16:36 GMT
Received: from xch-aln-001.cisco.com (173.36.7.11) by XCH-ALN-012.cisco.com (173.36.7.22) with Microsoft SMTP Server (TLS) id 15.0.1104.5; Mon, 9 Nov 2015 17:16:36 -0600
Received: from xch-aln-001.cisco.com ([173.36.7.11]) by XCH-ALN-001.cisco.com ([173.36.7.11]) with mapi id 15.00.1104.000; Mon, 9 Nov 2015 17:16:36 -0600
From: "Les Ginsberg (ginsberg)" <ginsberg@cisco.com>
To: "Acee Lindem (acee)" <acee@cisco.com>, Manav Bhatia <manavbhatia@gmail.com>
Thread-Topic: [OSPF] More Comments on OSPF S-BFD Discriminator
Thread-Index: AQHRD4JYrVG7ht7Ark2rdVyu2kC1qZ6OvTAAgAYDGgD//6hNoA==
Date: Mon, 9 Nov 2015 23:16:36 +0000
Message-ID: <c3caff28c3d243b99e523be8bc64719f@XCH-ALN-001.cisco.com>
References: <D252E730.385E8%acee@cisco.com> <CAG1kdojiU6fzn7XYSSdpfabxMDUQYvbgNNRCjZbraJKq2+WwJQ@mail.gmail.com> <D2668656.3CED2%acee@cisco.com>
In-Reply-To: <D2668656.3CED2%acee@cisco.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: [10.24.9.167]
Content-Type: multipart/alternative; boundary="_000_c3caff28c3d243b99e523be8bc64719fXCHALN001ciscocom_"
MIME-Version: 1.0
Archived-At: <http://mailarchive.ietf.org/arch/msg/ospf/iAKtaTBkKxy_8NsiFaUbN4RWlv4>
Cc: OSPF WG List <ospf@ietf.org>, "draft-ietf-ospf-sbfd-discriminator@ietf.org" <draft-ietf-ospf-sbfd-discriminator@ietf.org>
Subject: Re: [OSPF] More Comments on OSPF S-BFD Discriminator
X-BeenThere: ospf@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: The Official IETF OSPG WG Mailing List <ospf.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ospf>, <mailto:ospf-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ospf/>
List-Post: <mailto:ospf@ietf.org>
List-Help: <mailto:ospf-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ospf>, <mailto:ospf-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 09 Nov 2015 23:16:41 -0000

Acee –

While I can understand your struggle as to how to select one S-BFD discriminator from multiple advertised by a given node, I do not understand why you believe the IGPs have a responsibility to address this issue.

At the time both the OSPF and IS-IS S-BFD drafts were first being written this question was raised – and the response was that this was outside the scope of the IGP drafts. We included the ability to advertise multiple discriminators because it was easy to do and future proofed us against unanticipated requirements.  But this does not obligate the IGPs to address the mapping issue. I think Manav’s proposed text is both appropriate and adequate. (Of course I could be biased since the IS-IS draft says the same thing. ☺ )

Please explain what it is that you believe is required and why it should be addressed by the  IGP drafts.

   Les


From: OSPF [mailto:ospf-bounces@ietf.org] On Behalf Of Acee Lindem (acee)
Sent: Monday, November 09, 2015 2:24 PM
To: Manav Bhatia
Cc: draft-ietf-ospf-sbfd-discriminator@ietf.org; OSPF WG List
Subject: Re: [OSPF] More Comments on OSPF S-BFD Discriminator

Hi Manav,

From: Manav Bhatia <manavbhatia@gmail.com<mailto:manavbhatia@gmail.com>>
Date: Friday, November 6, 2015 at 11:35 AM
To: Acee Lindem <acee@cisco.com<mailto:acee@cisco.com>>
Cc: "draft-ietf-ospf-sbfd-discriminator@ietf.org<mailto:draft-ietf-ospf-sbfd-discriminator@ietf.org>" <draft-ietf-ospf-sbfd-discriminator@ietf.org<mailto:draft-ietf-ospf-sbfd-discriminator@ietf.org>>, "Alvaro Retana (aretana)" <aretana@cisco.com<mailto:aretana@cisco.com>>, OSPF WG List <ospf@ietf.org<mailto:ospf@ietf.org>>
Subject: Re: [OSPF] More Comments on OSPF S-BFD Discriminator

Hi Acee,

Sorry for the late response.

We will add the following text in the next update

“When multiple S-BFD discriminators are advertised how a given discriminator is mapped to a specific use case is out of scope for this document.”

I’m still struggling with the utility of automatic discovery of multiple S-BFD discriminators if one has no way to map them to an endpoint or the corresponding service.

Thanks,
Acee





Will address the other minor comments in the next rev.

Cheers, Manav

On Mon, Oct 26, 2015 at 5:37 AM, Acee Lindem (acee) <acee@cisco.com<mailto:acee@cisco.com>> wrote:
I have one major comments and I’ve copied Alvaro since he is reviewing the
base S-BFD drafts.

  If an OSPF router advertises multiple BFD discriminators, how do the
other OSPF routers in the OSPF routing domain map the S-BFD discriminators
to the OSPF router IP endpoints and services?

I also have some minor comments:

  1) This draft should reference the RFC 4970BIS draft as this is in RFC
EDIT state.
  2) Section 2.1 - The base RFC 4970BIS draft states that unrecognized
TLVs are ignored (as stated in section 3). This is not specific to this
TLV.
  3) Section 2.2 - This says the Opaque ID must be 0. Note that an OSPF
router can now originate multiple OSPF RI LSAs instances. I think this TLV
should be allowed in an OSPF RI LSA subsequent to the first.
  4) Section 2.2 - I don’t think we should advocate sending an empty OSPF
Router Information LSA. I’d remove this case.


Thanks,
Acee



_______________________________________________
OSPF mailing list
OSPF@ietf.org<mailto:OSPF@ietf.org>
https://www.ietf.org/mailman/listinfo/ospf