Re: [babel] Mirja Kühlewind's Discuss on draft-ietf-babel-rfc6126bis-12: (with DISCUSS and COMMENT)
Mirja Kuehlewind <ietf@kuehlewind.net> Thu, 22 August 2019 14:22 UTC
Return-Path: <ietf@kuehlewind.net>
X-Original-To: babel@ietfa.amsl.com
Delivered-To: babel@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 4CA90120025; Thu, 22 Aug 2019 07:22:35 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.897
X-Spam-Level:
X-Spam-Status: No, score=-1.897 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_NONE=0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
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 VXwdqhlgpogT; Thu, 22 Aug 2019 07:22:32 -0700 (PDT)
Received: from wp513.webpack.hosteurope.de (wp513.webpack.hosteurope.de [IPv6:2a01:488:42:1000:50ed:8223::]) (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 A39A1120103; Thu, 22 Aug 2019 07:22:32 -0700 (PDT)
Received: from 200116b82c40a9005947ae461257db2e.dip.versatel-1u1.de ([2001:16b8:2c40:a900:5947:ae46:1257:db2e]); authenticated by wp513.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) id 1i0nyu-0003bw-Lc; Thu, 22 Aug 2019 16:22:28 +0200
Content-Type: text/plain; charset="utf-8"
Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\))
From: Mirja Kuehlewind <ietf@kuehlewind.net>
In-Reply-To: <87imqzu1vc.wl-jch@irif.fr>
Date: Thu, 22 Aug 2019 16:22:27 +0200
Cc: draft-ietf-babel-rfc6126bis@ietf.org, d3e3e3@gmail.com, babel-chairs@ietf.org, babel@ietf.org, The IESG <iesg@ietf.org>
Content-Transfer-Encoding: quoted-printable
Message-Id: <0C555879-5AF3-487F-A65D-95918A546783@kuehlewind.net>
References: <156517737995.8257.5538554979559246700.idtracker@ietfa.amsl.com> <877e7m8b88.wl-jch@irif.fr> <1A2B2C1B-1536-4E75-A8D7-C5612FB8AEDA@kuehlewind.net> <87imqzu1vc.wl-jch@irif.fr>
To: Juliusz Chroboczek <jch@irif.fr>
X-Mailer: Apple Mail (2.3445.104.11)
X-bounce-key: webpack.hosteurope.de;ietf@kuehlewind.net;1566483752;cc53d8bb;
X-HE-SMSGID: 1i0nyu-0003bw-Lc
Archived-At: <https://mailarchive.ietf.org/arch/msg/babel/z-L6-FEQjFWZiiCYeRXl3o4jEX0>
Subject: Re: [babel] Mirja Kühlewind's Discuss on draft-ietf-babel-rfc6126bis-12: (with DISCUSS and COMMENT)
X-BeenThere: babel@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "A list for discussion of the Babel Routing Protocol." <babel.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/babel>, <mailto:babel-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/babel/>
List-Post: <mailto:babel@ietf.org>
List-Help: <mailto:babel-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/babel>, <mailto:babel-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 22 Aug 2019 14:22:35 -0000
Hi Juliusz, Please see below. > On 14. Aug 2019, at 18:51, Juliusz Chroboczek <jch@irif.fr> wrote: > >> I really don’t want to request to enforce a 3 second limit. However, >> I would like this draft to specify a limit or at minimum discuss >> suitable values for specific scenario. > > Appendix B specifies values that were found to be useful in etwo kinds of > realistic scenarios. > > The protocol structurally enforces minimum values of 10ms (time intervals > are carried on the wire in units of 10ms). Values that small are not > unrealistic over gigabit Ethernet (a full-size frame over GBE is sent in 12µs). I would like to propose the following: 1) Let's move appendix B into the body of the document. I think these are important information for an implementer and therefore it needs more attention. 2) Maybe you can add something like: The protocol structurally would allow for a minimum value of 10ms for the update interval, however, the update interval must be chosen carefully as such a low value could cause significant network load for slow links but may be a suitable for high speed link. I’m sure you have a better wording. My intention is simply to add another warning, to think carefully instead of just pick some default. > >>>> More concretely I think there are these cases that need more guidance: >>> >>> I agree. I've added a short discussion of packet pacing at the end of >>> 3.1, and I refer to it at suitable places. > >> Thanks. I was also hoping that you could make any recommendation on how >> to implement that e.g. a fixed delay of a certain (default) value or >> based on some other knowledge. If that is a SHOULD and no further >> implementation example is given, I would be afraid that the risk is high >> that people simple don’t implement this part. > > You do realise it's a very high bar you're setting? > > There exist standard techniques for packet pacing (static delay, dynamic > delay, deadline-first scheduling, etc.). I hope you're not requesting > that I transform this document in a tutorial about packet scheduling. > > I'll point out that RFC 5340 does not explain how to pace Dijkstra > recomputation. There's a good discussion of the issue in Gredler's book > about IS-IS. I have no idea whether Gredler's book reflects the behaviour > of modern implementations. I wasn’t looking for a tutorial for pacing but rather a reference to add. E.g. just naming different approaches for how to implement pacing and provide a reference would be a good thing I think. However, I will not block on this one thing. Your choice. > >>>> - Section 3.7.2. (Triggered Updates) advises to send a message multiple >>>> times for redundancy in case of loss. 5 and 2 are mentioned as example >>>> values. Please provide a normative default value and a normative maximum >>>> value here. > >>> Done for the normative max and recommendation to avoid tail loss. >>> I haven't made the default values normative. > >> Why not? > > What exact problem are we trying to solve here? Do you expect that the > current non-normative language will cause issues? Thanks for having a max value normatively there! I think that is the important part. And this is also not blocking for me anymore. I just wondering why you don’t call them default value rather then examples. I think specifying default value normatively would be more clear and is what we usually do in specs. However, I think in this case it will not make a huge practical difference. > >>>> - In section 4.1.1 the update interval needs a lower limit (e.g. 3 seconds) >>> >>> I strongly disagree. Sub-second convergence after a mobility event is >>> required in some networks. > >> (See above) Maybe then 0.1 seconds is a suitable minimum value…? > > As mentioned above, the protocol structurally imposes a lower bound of > 10ms, which is not unrealistic over GBE. > >>>> and a recommend default value would be could as well (Note that there >>>> are other part in section 3 where the update value is discussed as well). > >>> Appendix B. > >> I think this needs normative language in the body of the document. > > I'm sorry, Mirja, I disagree. See my comments about GBE above. > >>>> - Section 3.8.2.4. mentions network load when requests are sent to all >>>> neighbours after reboot. Please provide more guidance about how to pace out >>>> these requests. > >>> I've removed this section altogether. > >> Why? > > The mechanism is not essential, and we're unable to give more precise > guidance that applies across a wide range of networks. I prefer to remove > the mechanism rather than give bad advice. I think it would be good to have a note on network load when rebooting somewhere in the document. Maybe you can re-add a warning in the security considerations section? Mirja > > -- Juliusz > >
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… STARK, BARBARA H
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Juliusz Chroboczek
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… David Schinazi
- [babel] Mirja Kühlewind's Discuss on draft-ietf-b… Mirja Kühlewind via Datatracker
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Juliusz Chroboczek
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Juliusz Chroboczek
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Juliusz Chroboczek
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… David Schinazi
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Juliusz Chroboczek
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Juliusz Chroboczek
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… STARK, BARBARA H
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Juliusz Chroboczek
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Teco Boot
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Juliusz Chroboczek
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Teco Boot
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Juliusz Chroboczek
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Juliusz Chroboczek
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kuehlewind
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… Mirja Kühlewind (IETF)
- Re: [babel] Mirja Kühlewind's Discuss on draft-ie… David Schinazi