Re: Feedback on draft-hu-bier-bfd-02

"Reshad Rahman (rrahman)" <rrahman@cisco.com> Thu, 08 November 2018 05:22 UTC

Return-Path: <rrahman@cisco.com>
X-Original-To: rtg-bfd@ietfa.amsl.com
Delivered-To: rtg-bfd@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 940EE126CB6; Wed, 7 Nov 2018 21:22:50 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -14.969
X-Spam-Level:
X-Spam-Status: No, score=-14.969 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.47, 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
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 T3Z6WDeMCAkG; Wed, 7 Nov 2018 21:22:48 -0800 (PST)
Received: from rcdn-iport-1.cisco.com (rcdn-iport-1.cisco.com [173.37.86.72]) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id EC521126BED; Wed, 7 Nov 2018 21:22:47 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=27496; q=dns/txt; s=iport; t=1541654568; x=1542864168; h=from:to:cc:subject:date:message-id:references: in-reply-to:mime-version; bh=29xK0UJPNS5KsyobdHEQUmJ/ZhWI65Kw3WZeP363Do0=; b=c/SojJMs0NkdOOEC7QAfD6BSI6mQdzzN+kru0bvYdYUyviDJpV+f+g55 B0xTtb8nepcGD7urLOfirlyLv6jI3lv/d8wgtQJwJ3QeZ0PbQ/gHlxNMc 8euBIrrLlyGd5wuVh98ZssBGbtcMaNjlSmxbvgNQGFJe7Bd9U7kL/UHn4 k=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: =?us-ascii?q?A0AVAACVx+Nb/4sNJK1kGgEBAQEBAgE?= =?us-ascii?q?BAQEHAgEBAQGBVAIBAQEBCwGBDUgFKWaBAicKg26WIIkEkCgLAQGEbAIXgnI?= =?us-ascii?q?iNwoNAQMBAQIBAQJtKIU6AQEBAQMjCkwQAgEGAhEDAQIhBwMCAgIfERQJCAI?= =?us-ascii?q?EAQ0FG4MGAYEdTAMVjDObUIEuiAwNghmLeReBQT+BEScfgkyCVoF0VBaCTjG?= =?us-ascii?q?CJgKKBoRihi2KAS4JAo1mgyoYgVeFAQWKDI4jiSUCERSBJjMiJ4EucBVlAYJ?= =?us-ascii?q?BCYM0AQiNFEExjEKBHwEB?=
X-IronPort-AV: E=Sophos;i="5.54,478,1534809600"; d="scan'208,217";a="478420216"
Received: from alln-core-6.cisco.com ([173.36.13.139]) by rcdn-iport-1.cisco.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Nov 2018 05:22:46 +0000
Received: from XCH-ALN-003.cisco.com (xch-aln-003.cisco.com [173.36.7.13]) by alln-core-6.cisco.com (8.15.2/8.15.2) with ESMTPS id wA85Mkw0016108 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=FAIL); Thu, 8 Nov 2018 05:22:46 GMT
Received: from xch-rcd-005.cisco.com (173.37.102.15) by XCH-ALN-003.cisco.com (173.36.7.13) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Wed, 7 Nov 2018 23:22:45 -0600
Received: from xch-rcd-005.cisco.com ([173.37.102.15]) by XCH-RCD-005.cisco.com ([173.37.102.15]) with mapi id 15.00.1395.000; Wed, 7 Nov 2018 23:22:45 -0600
From: "Reshad Rahman (rrahman)" <rrahman@cisco.com>
To: Greg Mirsky <gregimirsky@gmail.com>, "hu.fangwei@zte.com.cn" <hu.fangwei@zte.com.cn>
CC: "draft-hu-bier-bfd@ietf.org" <draft-hu-bier-bfd@ietf.org>, BIER WG <bier@ietf.org>, "rtg-bfd@ietf.org" <rtg-bfd@ietf.org>
Subject: Re: Feedback on draft-hu-bier-bfd-02
Thread-Topic: Feedback on draft-hu-bier-bfd-02
Thread-Index: AQHUdxbNv+kW2bBAtEqB4REYCklGMKVFrROAgAAOSYD//61fAA==
Date: Thu, 8 Nov 2018 05:22:45 +0000
Message-ID: <F349A74B-663F-49CB-907B-1CC00FEFBFA4@cisco.com>
References: <CE547BEC-C580-4CC6-8B9B-CB22EE07E948@cisco.com> <201811081227199234176@zte.com.cn> <CA+RyBmV54zYMpq-+H66CxC_8XriAZmYt02tK3y_oo_mU1hj6-A@mail.gmail.com>
In-Reply-To: <CA+RyBmV54zYMpq-+H66CxC_8XriAZmYt02tK3y_oo_mU1hj6-A@mail.gmail.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
user-agent: Microsoft-MacOutlook/10.b.0.180311
x-ms-exchange-messagesentrepresentingtype: 1
x-ms-exchange-transport-fromentityheader: Hosted
x-originating-ip: [10.86.252.96]
Content-Type: multipart/alternative; boundary="_000_F349A74B663F49CB907B1CC00FEFBFA4ciscocom_"
MIME-Version: 1.0
X-Outbound-SMTP-Client: 173.36.7.13, xch-aln-003.cisco.com
X-Outbound-Node: alln-core-6.cisco.com
Archived-At: <https://mailarchive.ietf.org/arch/msg/rtg-bfd/XNeLSGRq9sTGy7utHfgZ7Um_XOg>
X-BeenThere: rtg-bfd@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "RTG Area: Bidirectional Forwarding Detection DT" <rtg-bfd.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtg-bfd>, <mailto:rtg-bfd-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/rtg-bfd/>
List-Post: <mailto:rtg-bfd@ietf.org>
List-Help: <mailto:rtg-bfd-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtg-bfd>, <mailto:rtg-bfd-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 08 Nov 2018 05:22:51 -0000

Thanks Greg and Fangwei. As discussed in BIER meeting, please add a reference to draft-xiong-bier-resilience.

Regards,
Reshad.

From: Greg Mirsky <gregimirsky@gmail.com>
Date: Thursday, November 8, 2018 at 12:18 PM
To: "hu.fangwei@zte.com.cn" <hu.fangwei@zte.com.cn>
Cc: "Reshad Rahman (rrahman)" <rrahman@cisco.com>om>, "draft-hu-bier-bfd@ietf.org" <draft-hu-bier-bfd@ietf.org>rg>, BIER WG <bier@ietf.org>rg>, "bfd@ietf.org" <bfd@ietf.org>
Subject: Re: Feedback on draft-hu-bier-bfd-02

Hi Reshad,
thank you for taking the time to review and sharing your comments, much appreciated. I'll add to answers by Fangwei, please find them in-line tagged GIM>>.

Regards,
Greg

On Thu, Nov 8, 2018 at 11:27 AM <hu.fangwei@zte.com.cn<mailto:hu.fangwei@zte.com.cn>> wrote:

Hi, Rahman

Thanks for your comments.

Plese see inline marked with[hfw].



>Hi,



>I just took a quick look at the draft:

>1.Section 1, 2nd paragraph mentions “…detect unicast failures..”, I believe this  should be unidirectional?

[hfw] Agree, the BFD multipoint document only defines the unidirectional deteck from header to one or more tails.
GIM>> Great catch, thank you. Will fix in the next version.

>2.Section 1, 3rd paragraph says that active-tail is for further study. So when a tail detects a failure, how will the head be notified?  If the head does not have to be notified, what action is taken?

[hfw] Ok. Actually, we are considering the active-tails solution. It  will be added in the next version.
GIM>> Our plan is to use BFD for Multipoint Network with Active Tail specfication as the base for this mode. Since tails in p2mp BFD are in the Demand mode the head only can query all tail and/or the particular tail using the Poll sequence (referred as multicast and unicast Poll). Depending on the type of the failure, the head may recieve or not the BFD control message with Final flag set. Absence of the response in combination with the content of the Diag field must be used to draw the conclusion on liveleness of the path from the head to the particular tail. From here the head may use BIER Ping to localize the defect and switch to using the alternative path through the BIER domain by using different transient BFRs.



Regards

Fangwei.
发件人:ReshadRahman(rrahman) <rrahman@cisco.com<mailto:rrahman@cisco.com>>
收件人:draft-hu-bier-bfd@ietf.org<mailto:draft-hu-bier-bfd@ietf.org> <draft-hu-bier-bfd@ietf.org<mailto:draft-hu-bier-bfd@ietf.org>>;
抄送人:bier@ietf.org<mailto:bier@ietf.org> <bier@ietf.org<mailto:bier@ietf.org>>;bfd@ietf.org<mailto:bfd@ietf.org> <bfd@ietf.org<mailto:bfd@ietf.org>>;
日 期 :2018年11月08日 11:56
主 题 :Feedback on draft-hu-bier-bfd-02
Hi,

I just took a quick look at the draft:

  1.  Section 1, 2nd paragraph mentions “…detect unicast failures..”, I believe this  should be unidirectional?
  2.  Section 1, 3rd paragraph says that active-tail is for further study. So when a tail detects a failure, how will the head be notified?  If the head does not have to be notified, what action is taken?

Regards,
Reshad.