Re: Correcting BFD Echo model

Mahesh Jethanandani <mjethanandani@gmail.com> Mon, 27 February 2017 04:33 UTC

Return-Path: <mjethanandani@gmail.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 0354F1296F2; Sun, 26 Feb 2017 20:33:13 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.998
X-Spam-Level:
X-Spam-Status: No, score=-1.998 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.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 bWj8voWxjUcQ; Sun, 26 Feb 2017 20:33:11 -0800 (PST)
Received: from mail-pg0-x231.google.com (mail-pg0-x231.google.com [IPv6:2607:f8b0:400e:c05::231]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 2FFBD127058; Sun, 26 Feb 2017 20:33:11 -0800 (PST)
Received: by mail-pg0-x231.google.com with SMTP id p5so14703182pga.1; Sun, 26 Feb 2017 20:33:11 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc:message-id:references :to; bh=9n8la2ZfNW7HKyZ8wJwfbqDgBamgoHTD962lw1+iOzU=; b=P3ZKkSLAjIVME5Lfku2OepGBar1MfAcVVqFJNJR2k2weaDFWxFDnbBj8W84BJoggAX +wjdo6Vd0RxqGtRtWbAQjVhc2BGG+4pQmgsNZu7zvPjfhbVWazNHy/PT/FNN06hHvrRs SeiRgooFiOdDc7z7+iyiryvLoFkWhaBSXwWVDIdY4RWg0fgpQydg5wPXf65H7UtfhHY+ 8ShVzg3gYOJP8E+h4D52Qd8T2yiC4bH+WpdS5BOBGzJFpXXLvs/jf/WcF4szxjvtL8rs s/Td1sfLXv3g5i2cUOLNP41OX0OGo9IrGfHxjADExuwj37rkj+v9THHsJTDkMxlWkOkT xGvQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :message-id:references:to; bh=9n8la2ZfNW7HKyZ8wJwfbqDgBamgoHTD962lw1+iOzU=; b=jp9UbuFcsApZgqieRrOlJf5fz93ZfJk0h6p0vOh7pFCvpl9viTv1qIPTfswO7AQrBJ 8psS14L9QhBsDGTFMHuIO/97jMJZ91WYhTWXsNjZCj0AA5tUXFph0AU4YywGQ/Io6Wqh qZ07cJ8MyklamF+lt0F76pM3ro3fVdJ/QHY25piGgmy9nxnej5b+OwslpNvjP/iMO3gX hUFMu/S7qxQQVFggMaaDRp5ES1vUUrSZXmWP5qGl4ZsOvvD+BRJbekWy3H4sd/j9r6M2 QgYnzfahqMyIXaHNTohrtM+//i7PEYK0fHtuIVoLC6j0uqSgyeO14idD/EKoys38oW// 1Spg==
X-Gm-Message-State: AMke39kdZQLe2THkOsAWvk6oeJPnF3Cfe6KsNgYFEgiT9fbUly10zeFloyd346vM8PMcdw==
X-Received: by 10.84.210.228 with SMTP id a91mr2876328pli.120.1488169990683; Sun, 26 Feb 2017 20:33:10 -0800 (PST)
Received: from mahesh-m-m8d1.attlocal.net ([2602:306:cf77:df90:3034:ab32:9822:dd2a]) by smtp.gmail.com with ESMTPSA id 85sm15473248pfz.15.2017.02.26.20.33.07 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 26 Feb 2017 20:33:09 -0800 (PST)
Content-Type: multipart/alternative; boundary="Apple-Mail=_1657134F-4A55-4727-87CD-1E8CD752E93A"
Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\))
Subject: Re: Correcting BFD Echo model
From: Mahesh Jethanandani <mjethanandani@gmail.com>
In-Reply-To: <CA+RyBmWyQZs5B3LG8x=ZoVXTkiHhGPzbZwRX70jCyT_MpQwzCA@mail.gmail.com>
Date: Sun, 26 Feb 2017 20:33:04 -0800
Message-Id: <E308FD25-A695-498C-8E34-756250776CE4@gmail.com>
References: <CA+RyBmWcU79iCBYM_bi__Ce1RpWwNn_jZCkPHv3Sc+qtybt_pg@mail.gmail.com> <D4D8BE31.25AE5C%rrahman@cisco.com> <CA+RyBmWyQZs5B3LG8x=ZoVXTkiHhGPzbZwRX70jCyT_MpQwzCA@mail.gmail.com>
To: Greg Mirsky <gregimirsky@gmail.com>
X-Mailer: Apple Mail (2.3124)
Archived-At: <https://mailarchive.ietf.org/arch/msg/rtg-bfd/KQjQoMz-XRqST4M_mtdH5ztIxQs>
Cc: "Reshad Rahman (rrahman)" <rrahman@cisco.com>, "rtg-bfd@ietf. org" <rtg-bfd@ietf.org>, "draft-ietf-bfd-yang@ietf.org" <draft-ietf-bfd-yang@ietf.org>
X-BeenThere: rtg-bfd@ietf.org
X-Mailman-Version: 2.1.17
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: Mon, 27 Feb 2017 04:33:13 -0000

> On Feb 26, 2017, at 4:39 PM, Greg Mirsky <gregimirsky@gmail.com> wrote:
> 
> Hi Reshad,
> thank you for the question. Here's my reasoning:
> only Required Min Echo RX Interval is present in RFC 5880 and it allows to indicate not only the smallest interval between consecutive BFD Echo packets but whether system supports BFD Echo function at all;
> since BFD Echo may be transmitted only when the session state is Up, operator is fully equipped to learn the value of Required Min Echo RX Interval of its BFD peer and to set Echo transmit interval accordingly;
> requesting BFD Echo, in my opinion, is no different from requesting IP ping or LSP ping.
> Hence my conclusion - transmit interval for BFD Echo is more suitable in RPC then as configuration parameter.

I do not think that is reason enough for it to be a RPC.

A RPC is an operation one defines in the YANG model specifying both input and output parameters. There are no operations to be had here.

And the definition and desired behavior of desired-min-echo-tx-interval is not very different from required-min-echo-x-interval. It is as the definition says, a configuration parameter that can be set, with zero having a special meaning in both cases.

> 
> Regards,
> Greg
> 
> On Sun, Feb 26, 2017 at 2:52 PM, Reshad Rahman (rrahman) <rrahman@cisco.com <mailto:rrahman@cisco.com>> wrote:
> Hi Greg,
> 
> Can you please explain why you believe this should go in RPC?
> 
> Regards,
> Reshad.
> 
> From: Greg Mirsky <gregimirsky@gmail.com <mailto:gregimirsky@gmail.com>>
> Date: Saturday, February 25, 2017 at 6:48 PM
> To: "rtg-bfd@ietf.org <mailto:rtg-bfd@ietf.org>" <rtg-bfd@ietf.org <mailto:rtg-bfd@ietf.org>>, "draft-ietf-bfd-yang@ietf.org <mailto:draft-ietf-bfd-yang@ietf.org>" <draft-ietf-bfd-yang@ietf.org <mailto:draft-ietf-bfd-yang@ietf.org>>
> Subject: Correcting BFD Echo model
> Resent-From: <alias-bounces@ietf.org <mailto:alias-bounces@ietf.org>>
> Resent-To: <vero.zheng@huawei.com <mailto:vero.zheng@huawei.com>>, Reshad <rrahman@cisco.com <mailto:rrahman@cisco.com>>, <mjethanandani@gmail.com <mailto:mjethanandani@gmail.com>>, <santosh.pallagatti@gmail.com <mailto:santosh.pallagatti@gmail.com>>, <gregimirsky@gmail.com <mailto:gregimirsky@gmail.com>>
> Resent-Date: Saturday, February 25, 2017 at 6:48 PM
> 
> Dear All,
> I've reviewed the BFD YANG model and now I'm thinking that desired-min-echo-tx-interval and attributing to it the behavior, i.e. when the value is 0, of Required Min Echo RX Interval are not in the right place. I think that definition of desired transmit interval of BFD Echo should be in corresponding RPC definition, not in configuration part of the model.
> Appreciate your comments.
> 
> Regards,
> Greg
>