Re: WGLC for BFD Multipoint documents (last round)

Greg Mirsky <> Sat, 16 December 2017 21:31 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id D46AB124234 for <>; Sat, 16 Dec 2017 13:31:48 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.698
X-Spam-Status: No, score=-2.698 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_LOW=-0.7, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id rLxQ_nxmtA77 for <>; Sat, 16 Dec 2017 13:31:46 -0800 (PST)
Received: from ( [IPv6:2a00:1450:4010:c07::22e]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id BE645120227 for <>; Sat, 16 Dec 2017 13:31:45 -0800 (PST)
Received: by with SMTP id f18so13946504lfg.8 for <>; Sat, 16 Dec 2017 13:31:45 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=WqJ44EgJDsZhvDWljeQNQrqbQQFpuxNkOyBOOBwB4hg=; b=VS/5CsLQ+MBGpX6KgHFCUoL6z7yzFV81UeXt8mNjDC1EA/PX/E7XCDuhCvKJn5U0fV Ls7Y2KxsIynEuRv+OMFE5f7itB4xH+xCxYvea/vFJ/O+wsPFUV4ZAXrzBEUb7KNC9RF9 i/oYqCzOYM9Ts3v3R5bwmo5b134O/+VU044JLR8cxjTeq45QKXdmj9m1eQpLpC8LVsob 1zthaqCzWru2l4MrGJDqQBKr581N7oEKDUdlE12d5LLPteFB+3V4yPgJNDxRUf2tMnf1 cCCH0WnEi1qvCjHtvhy0i3SN+kSNMKuXbCXZqnB18EsoEErhb6QRl4BFbMkw43eu4p0J P+vw==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=WqJ44EgJDsZhvDWljeQNQrqbQQFpuxNkOyBOOBwB4hg=; b=Pfwmm1HBB82XdC3JiL3QxXmcrBe+/PTG8yQ7JhqfG+LcxLqkG9kUfLsSrPtvVCBdVg 0oSg9uiMOf6ToMSRud0+DXtyKliXPFO2cZCKrmxwGPXcyXj0TGVguqFdaaGP5HU3T7KS 9rsbVLlIbSYPS6m8jjVA1d/xKpa82uxUGLUTWhZjt7tEaql0Vg7j36JbM/iONkfINTgf O98jt78UhbiwQsu9T/ScPnha0cWfVVwId15DoWyzMfHM987KHy7rvq3sM3ncXV5PCVFh whPgFVjUdr+4V2scqCDe4MuFl0dKKzAbDA4Px0v6JcX9cf8I6AI8Kf1GlBpmdLXt8RR+ Om7g==
X-Gm-Message-State: AKGB3mJYp9hzwZuXH+wIN4AeeK5XYZO3oGf6P87CVDuKwJC2X94VowRM Wyhwv5Oeu0gciwJdSOWYDqtVult5YiDMxqrSwwo=
X-Google-Smtp-Source: ACJfBotwve3ndCIUsi7mJsgqL1VxA38aaICBfdJkPzqknQ1UYbidfZ7AawOlhPvlI5gMFjdR/SOizewU5AdVG5QMSsA=
X-Received: by with SMTP id h29mr8134127ljb.144.1513459903848; Sat, 16 Dec 2017 13:31:43 -0800 (PST)
MIME-Version: 1.0
Received: by with HTTP; Sat, 16 Dec 2017 13:31:43 -0800 (PST)
In-Reply-To: <>
References: <> <> <>
From: Greg Mirsky <>
Date: Sat, 16 Dec 2017 15:31:43 -0600
Message-ID: <>
Subject: Re: WGLC for BFD Multipoint documents (last round)
To: "Carlos Pignataro (cpignata)" <>
Cc: Jeffrey Haas <>, "" <>
Content-Type: multipart/alternative; boundary="94eb2c1ce7faf36ac505607bd713"
Archived-At: <>
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: "RTG Area: Bidirectional Forwarding Detection DT" <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Sat, 16 Dec 2017 21:31:49 -0000

Hi Carlos,
thank you very much for pointing this out. Sorry I've missed it. I agree
that it requires resolution but I think that the resolution is different
from what you've proposed in your original comment. The names of the new
variable in RFC 7880 and
draft-ietf-bfd-multipoint/draft-ietf-bfd-multipoint-active-tails are
identical but, I believe, semantics are different:

   - RFC 7880 uses bfd.SessionType to reflect S-BFD role the node performs
   in S-BFD session
   - draft-ietf-bfd-multipoint-* are using bfd.SessionType to reflect
   topology of the BFD session, i.e. whether it is p2p or p2mp

S-BFD currently specified for p2p but I don't see a reason why S-BFD cannot
be applied to p2mp cases. So, for a BFD node that supports both RFC 7880
and draft-ietf-bfd-multipoint values of variables may be SBFDInitiator and
PointToPoint. And, at some time, there will be interest to define behavior
of the SBFDInitiator/MultipointHead and SBFDReflector/MultipointTail

Thus I see this issue as name conflict that can be resolved by changing the
name in draft-ietf-bfd-multipoint-* to something other than
bfd.SessionType. Perhaps we can change the name to bfd.SessionTopology.

Greatly appreciate comments, suggestions. Let's make holiday presents to
our AD!


On Fri, Dec 15, 2017 at 10:02 PM, Carlos Pignataro (cpignata) <>; wrote:

> Hi, Greg,
> It seems the comments regarding bfd.SessionType are not addressed:
> Thanks,
> Sent from my iPad
> On Dec 15, 2017, at 5:15 PM, Greg Mirsky <>; wrote:
> Dear All,
> attached please find diffs and the updated version of the
> draft-ietf-bfd-multipoint-active-tail. All changes are editorial. Please
> review changes and share your comments.
> Regards,
> Greg
> On Wed, Dec 13, 2017 at 11:24 AM, Jeffrey Haas <>; wrote:
>> Working Group,
>> In an attempt to give our AD a holiday gift, we're at the point where we
>> may
>> now work to conclude WGLC on the BFD multipoint documents.  We did one
>> pass
>> of last call June-July of this year, and held off approval pending review
>> from ALU who has an implementation of the base spec.  ALU has since
>> responded that they're fine with the contents.
>> To provide the working group one last opportunity to review the documents,
>> we're running a final last call and will send off the changes to our AD
>> afterward.
>> The prior WGLC thread is here:
>> niDGdqPioSt_w/?qid=2d0831389d19508c66f9a387096250e6
>> The documents are here:
>> The intent is to conclude this WGLC at end of year.
>> -- Jeff
> <draft-ietf-bfd-multipoint-active-tail-06.txt>
> <Diff_ draft-ietf-bfd-multipoint-active-tail-05.txt -
> draft-ietf-bfd-multipoint-active-tail-06.txt.html>