IETF Logo Mail Archive

Re: Correcting BFD Echo model

"Reshad Rahman (rrahman)" <rrahman@cisco.com> Fri, 24 March 2017 22:35 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 D9DD4128CD5; Fri, 24 Mar 2017 15:35:46 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -14.523
X-Spam-Level:
X-Spam-Status: No, score=-14.523 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=-0.001, SPF_HELO_PASS=-0.001, 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 sgcZsxcpeIkl; Fri, 24 Mar 2017 15:35:45 -0700 (PDT)
Received: from rcdn-iport-2.cisco.com (rcdn-iport-2.cisco.com [173.37.86.73]) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 2A24512894A; Fri, 24 Mar 2017 15:35:45 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=1660; q=dns/txt; s=iport; t=1490394945; x=1491604545; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-id:content-transfer-encoding: mime-version; bh=UgyXpdinDH3zKmU06SKcHVJjP2+pm0FNeRJ05tHDbMg=; b=NH8cD++oVHIW+cajr147eeD4pxaozWaIsaBlgmGpsYDZn4ZQOITsozSE oXKEWdbjHKHi17J4YFEZO3qm36lmVepGuS+Io43f50RBP4W7fq6FqZrv6 DqvuwJKkU1O9TGsgak1Vz3RRlJjoj5lVQ8oefT96SGAQZTmd7yWuRnWQK M=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: A0AVAQC3ntVY/4ENJK1dGQEBAQEBAQEBAQEBBwEBAQEBg1SBbAeNapFPiBaNM4IOhiICgyk/GAECAQEBAQEBAWsohRUBAQEBAgF5EAIBCA4KLiERJQIEAQ0FiW8DDQisd4czDYMHAQEBAQEBAQEBAQEBAQEBAQEBAR+GToRvglGCA4VlAQSQIYt+OgGOFIQ2kTCKbYh3AR84gQRZFYcZdYh6gQ0BAQE
X-IronPort-AV: E=Sophos;i="5.36,216,1486425600"; d="scan'208";a="227593597"
Received: from alln-core-9.cisco.com ([173.36.13.129]) by rcdn-iport-2.cisco.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 24 Mar 2017 22:35:43 +0000
Received: from XCH-ALN-019.cisco.com (xch-aln-019.cisco.com [173.36.7.29]) by alln-core-9.cisco.com (8.14.5/8.14.5) with ESMTP id v2OMZhmR011584 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=FAIL); Fri, 24 Mar 2017 22:35:43 GMT
Received: from xch-rcd-005.cisco.com (173.37.102.15) by XCH-ALN-019.cisco.com (173.36.7.29) with Microsoft SMTP Server (TLS) id 15.0.1210.3; Fri, 24 Mar 2017 17:35:42 -0500
Received: from xch-rcd-005.cisco.com ([173.37.102.15]) by XCH-RCD-005.cisco.com ([173.37.102.15]) with mapi id 15.00.1210.000; Fri, 24 Mar 2017 17:35:42 -0500
From: "Reshad Rahman (rrahman)" <rrahman@cisco.com>
To: Jeffrey Haas <jhaas@pfrc.org>, Greg Mirsky <gregimirsky@gmail.com>
CC: "Carlos Pignataro (cpignata)" <cpignata@cisco.com>, "rtg-bfd@ietf. org" <rtg-bfd@ietf.org>, "draft-ietf-bfd-yang@ietf.org" <draft-ietf-bfd-yang@ietf.org>
Subject: Re: Correcting BFD Echo model
Thread-Topic: Correcting BFD Echo model
Thread-Index: AQHSj8Gxk5FkqTOyS0attHx6x8g/UaF791cAgABxigCAAEFcAIAAGoQAgAAvKQCAAG4ngIAnPeUAgAAzPgCAAAKYgIAAAsaAgAAFgAD///EfgA==
Date: Fri, 24 Mar 2017 22:35:42 +0000
Message-ID: <D4FAF2A9.26E892%rrahman@cisco.com>
References: <CA+RyBmWcU79iCBYM_bi__Ce1RpWwNn_jZCkPHv3Sc+qtybt_pg@mail.gmail.com> <D4D8BE31.25AE5C%rrahman@cisco.com> <CA+RyBmWyQZs5B3LG8x=ZoVXTkiHhGPzbZwRX70jCyT_MpQwzCA@mail.gmail.com> <E308FD25-A695-498C-8E34-756250776CE4@gmail.com> <CA+RyBmW=t0DH5H_UVau8t5rS_1A8Qpsh478ayVUN=Se6qqKHyg@mail.gmail.com> <D4D9967A.25B679%rrahman@cisco.com> <CA+RyBmV9QiGGCgxxEHmC8GjnecHksjfZgVO3NJ5q2aLSSrZMvA@mail.gmail.com> <20170324154640.GO27015@pfrc.org> <CA+RyBmUE3g1gNTtf30Wr7hvgMhahnuCznt7LY77kLGSXNYQ=Xg@mail.gmail.com> <F6DB90E6-B6DF-4175-83DC-188CDEF2D67F@cisco.com> <CA+RyBmWsy=dhzH3Fpe+4o20BgVWduKuQrpkFyyyOhfGWq+aVtg@mail.gmail.com> <3708AF72-D97F-4C79-B3B2-C5C68F942395@pfrc.org>
In-Reply-To: <3708AF72-D97F-4C79-B3B2-C5C68F942395@pfrc.org>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
user-agent: Microsoft-MacOutlook/14.6.8.160830
x-ms-exchange-messagesentrepresentingtype: 1
x-ms-exchange-transport-fromentityheader: Hosted
x-originating-ip: [10.86.242.190]
Content-Type: text/plain; charset="iso-8859-1"
Content-ID: <18F33A6D5CEBEB40B2EA52ECC0679EC1@emea.cisco.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Archived-At: <https://mailarchive.ietf.org/arch/msg/rtg-bfd/PusCogj1ZR-w1CPpkZF2gra2QPU>
X-BeenThere: rtg-bfd@ietf.org
X-Mailman-Version: 2.1.22
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: Fri, 24 Mar 2017 22:35:47 -0000

I am familiar with an implementation which supports echo and reduces rate
of control packets when echo is enabled. In that implementation, the
configuration has desired interval and multiplier, there isn¹t different
timer configurations for async and echo. Echo is enabled by default but
there is config knob to disable echo. The operational model does show the
rates at which control and echo packets are being transmitted.


But back to Greg¹s original question, I¹d like to hear from other BFD
implementations which support echo. Is echo enabled "on demand² e.g. For a
small duration like ping, or is it continuous?

Regards,
Reshad.

On 2017-03-24, 3:28 PM, "Jeffrey Haas" <jhaas@pfrc.org> wrote:

>
>> On Mar 24, 2017, at 3:09 PM, Greg Mirsky <gregimirsky@gmail.com> wrote:
>> 
>> Hi Carlos,
>> indeed, the RFC 5880 does explain that the rate of BFD control packets
>>transmitted in Async mode may be reduced when Echo is activated. If
>>anyone is familiar with such implementation, I'd be glad to learn and
>>discuss how this mechanism affects the data model. Regrettably, I don't
>>have personal experience with using or implementing such mechanism.
>
>My *suspicion* is that the configuration would represent a set of
>parameters for both async mode and echo mode.  These will not alter
>themselves automatically.
>
>The operational mode might reflect timers that have backed off.  However,
>this is also true if an implementation does various forms of session
>auto-tuning.  An example I'm aware of is a decrease in timer
>aggressiveness as part of a high availability switchover event.
>
>-- Jeff
>

v2.23.0 | Report a Bug | By Email