Re: [Detnet] Transport sub-layer name change (Was Re: Tsvart last call review of draft-ietf-detnet-architecture-08)
"Andrew G. Malis" <agmalis@gmail.com> Thu, 13 December 2018 20:44 UTC
Return-Path: <agmalis@gmail.com>
X-Original-To: detnet@ietfa.amsl.com
Delivered-To: detnet@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 3F0ED130F4C; Thu, 13 Dec 2018 12:44:06 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.999
X-Spam-Level:
X-Spam-Status: No, score=-1.999 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] 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 fzxok-sU7BfR; Thu, 13 Dec 2018 12:44:00 -0800 (PST)
Received: from mail-qt1-x82e.google.com (mail-qt1-x82e.google.com [IPv6:2607:f8b0:4864:20::82e]) (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 A06EB130E95; Thu, 13 Dec 2018 12:43:58 -0800 (PST)
Received: by mail-qt1-x82e.google.com with SMTP id k12so3760735qtf.7; Thu, 13 Dec 2018 12:43:58 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Z6qDdE3HfPaTNIPdAJT2C0Xb0Vec73Q9cc8AO07I+jE=; b=WYIb82NWu58pHklobOJqAH9m78L5MJS80KTSh44BKLnjZsn1URw2Ky9wkPfgteQRGL cMsV42H+avzMkdvOWFQvMCKSUOfXSCX8zGN0Xf89wvE3hRiePeyBGcsqCtn/BgD9D39o QzYwJKFNRlkFsXSZxuPA7CBTzsv+9+4NPpaRmqwa03JRzVM+0wE3CBrObmqMc+BHIEUq I8SRCk2yYxUeTx5YRF+G2SLFiAtFc+US+7wi5T28X68Evjhkn2qIoKwIqbt+lQQJ3KRL 3U/nFTUha/XFw2lC1+dHokDtIOmGkqgsTEK7FAo/ugw9qs7NbFqwaagUvyRDUDrMVc8M zlpA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Z6qDdE3HfPaTNIPdAJT2C0Xb0Vec73Q9cc8AO07I+jE=; b=Qcs1XN0GdiugudZR+gdtwlibmCYDZy1LrxpUTpDOZkpPKdp2csvLCdEaYrHmYKbfiR Tu8OrnN5B0fNg0WatIq/Gve9q5hJK5gDTyApLPcliyozkq+CBkKF2LbZX1NzvIHZqDkB S6M9moEkZcONDdhgVL3TvsTgyeVfGr5+9wPMrbgAukuZPb/0Hk30ujr8ZBNd3JEUTj4B 3eIPtL0fQuYVKNXjgWoDSASPeYak2T+RlkR/Hvgi+fapRH4SVP778PtxsOKd6CjJQ7qZ sjQp5Zf49nFCIAc6h2xbeklQod3QbQOK+CLMc2iwCF3Pvxgi/Z1vzIMY1B3O1oPTJFpt mraA==
X-Gm-Message-State: AA+aEWZJhuHM1BA41KNH4VE1eoG4bUHDGNIDGPOIluxMQGHNNPMFlEgQ +hIW7PzJuZ+4prldUWha1xjLXc/5/+ez9HPdXAbXxA==
X-Google-Smtp-Source: AFSGD/VZswuMKn28zTNDLSOX0sWm5aD1/F0qV8aY1sNbSqt7QzVH+ijhIEng4GlQBFLOzUFzPpM4LzuE3etb+GwxyaQ=
X-Received: by 2002:aed:2cc4:: with SMTP id g62mr307586qtd.192.1544733837548; Thu, 13 Dec 2018 12:43:57 -0800 (PST)
MIME-Version: 1.0
References: <153817345967.27205.135001179751151278@ietfa.amsl.com> <fdf872d6-08a6-2c33-de21-9dd1506c1d21@labn.net> <6EC6417807D9754DA64F3087E2E2E03E2D16A4D3@rznt8114.rznt.rzdir.fht-esslingen.de> <e38ab4d6-0924-ab60-b1dc-4ac26600044c@labn.net> <16c050e436f342bb94b1ec9d1a38da3e@XCH-RCD-001.cisco.com> <3adfa63a-e6de-b899-f7ce-79d8f668d40f@labn.net> <5164e2e0-f4ff-331c-11e0-deb080d1c520@labn.net> <CAA=duU1P3qzhC1J1xo5n7QVe-U9Ais6NHTLNJU+49_WYXSoFpg@mail.gmail.com> <cb649750-5c1a-481f-7561-fb04491f0b72@labn.net> <CAA=duU0CY9nirx5sryOWSmqgUMWBNnB_90t9iVD9JNcaFvHAVw@mail.gmail.com> <3e977a3c-bd91-99d4-3d27-05488f0892ce@labn.net>
In-Reply-To: <3e977a3c-bd91-99d4-3d27-05488f0892ce@labn.net>
From: "Andrew G. Malis" <agmalis@gmail.com>
Date: Thu, 13 Dec 2018 15:43:46 -0500
Message-ID: <CAA=duU3u1LdoJn_yokny_PWCXppaQZLQTegqRzz7ZHYa97AZ=g@mail.gmail.com>
To: Lou Berger <lberger@labn.net>
Cc: "Pascal Thubert (pthubert)" <pthubert@cisco.com>, Michael.Scharf@hs-esslingen.de, draft-ietf-detnet-architecture.all@ietf.org, detnet WG <detnet@ietf.org>
Content-Type: multipart/alternative; boundary="000000000000a8e105057ced5fe8"
Archived-At: <https://mailarchive.ietf.org/arch/msg/detnet/kTOhjo8agdgp-i17ytUpPskW2iY>
Subject: Re: [Detnet] Transport sub-layer name change (Was Re: Tsvart last call review of draft-ietf-detnet-architecture-08)
X-BeenThere: detnet@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Discussions on Deterministic Networking BoF and Proposed WG <detnet.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/detnet>, <mailto:detnet-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/detnet/>
List-Post: <mailto:detnet@ietf.org>
List-Help: <mailto:detnet-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/detnet>, <mailto:detnet-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 13 Dec 2018 20:44:07 -0000
Lou, Yes, but not SRv6 explicitly, as opposed to explicitly both MPLS TE LSPs and SR-MPLS. But my question was answered, so I'm good! :-) Thanks, Andy On Thu, Dec 13, 2018 at 3:41 PM Lou Berger <lberger@labn.net> wrote: > IPv6 *is* there ;-) > > On 12/13/2018 3:29 PM, Andrew G. Malis wrote: > > Lou, > > > > Thanks, that's what I thought, but I didn't see it in your list of > > DetNet Forwarding sub-layer protocols. > > > > Cheers. > > Andy > > > > > > On Thu, Dec 13, 2018 at 1:55 PM Lou Berger <lberger@labn.net > > <mailto:lberger@labn.net>> wrote: > > > > Hi Andy, > > > > As SRv6 is implemented using an IPv6 routing header the figure below > > accurately shows IPv6 (and consequently SRv6) as being part of the > > Forwarding sub-layer. > > > > In case you were really asking if use of SRv6 is in scope of > > DetNet WG, > > I don't see anything in the charter that would preclude the WG > > working > > on DetNet SRv6. > > > > Lou > > > > On 12/13/2018 1:16 PM, Andrew G. Malis wrote: > > > Lou, > > > > > > I think we've discussed this before, but I wanted to confirm > > whether > > > SRv6 is in scope for the DetNet Forwarding sub-layer. > > > > > > Thanks, > > > Andy > > > > > > > > > On Thu, Dec 13, 2018 at 12:47 PM Lou Berger <lberger@labn.net > > <mailto:lberger@labn.net> > > > <mailto:lberger@labn.net <mailto:lberger@labn.net>>> wrote: > > > > > > Hi, > > > > > > My reading is that the WG has settled on: > > > > > > +----------------------------+ > > > | DetNet Service sub-layer | PW, UDP, GRE > > > +----------------------------+ > > > | DetNet Forwarding sub-layer| IPv6, IPv4, MPLS TE LSPs, > > > MPLS SR > > > +----------------------------+ > > > . > > > . > > > > > > Figure 4: DetNet adaptation to data plane > > > > > > Authors, (of detnet-architecture) > > > Please work to have the next rev of the draft reflect this > > > change. > > > > > > Thank you to all who participated in the discussion! > > > Lou > > > (as co-chair and doc shepherd) > > > > > > On 11/20/2018 1:18 PM, Lou Berger wrote: > > > > ALL, > > > > > > > > There is a desire to replace the word "Transport" from the > > DetNet > > > > Transport sub-layer to avoid confusion with L$ Transport > > protocols. > > > > > > > > In the TEAS WG we had a similar discussion and we replaced > > > "Transport" > > > > with "Traffic Engineered (TE) ". > > > > > > > > While a bit more verbose, what do people think about this > > change? > > > > > > > > To be clear, the suggestion is: > > > > > > > > OLD > > > > > > > > . > > > > . > > > > +----------------------------+ > > > > | DetNet Service sub-layer | PW, UDP, GRE > > > > +----------------------------+ > > > > | DetNet Transport sub-layer | IPv6, IPv4, MPLS TE > > LSPs, > > > MPLS SR > > > > +----------------------------+ > > > > . > > > > . > > > > > > > > Figure 4: DetNet adaptation to data plane > > > > > > > > NEW > > > > > > > > . > > > > . > > > > +----------------------------+ > > > > | DetNet Service sub-layer | PW, UDP, GRE > > > > +----------------------------+ > > > > | DetNet TE sub-layer | IPv6, IPv4, MPLS TE > > LSPs, > > > MPLS SR > > > > +----------------------------+ > > > > . > > > > . > > > > > > > > Figure 4: DetNet adaptation to data plane > > > > > > > > Lou > > > > > > > > On 11/20/2018 11:21 AM, Pascal Thubert (pthubert) wrote: > > > >> Hello Lou: > > > >> > > > >> > > > >> About ' discuss changing the name of the "DetNet Transport > > > sub-layer" to avoid the word "transport". ' > > > >> > > > >> For one I'd like to make that call. The unfortunate name > > > collision has started to hurt us quite a bit already and people > > > are getting confused on very active exchanges we have on the > > > mailing list. > > > >> > > > >> I tend to agree that for the general IETF "transport" > > generally > > > means "L4". Even point one in your email uses "transport" > > that way > > > I guess. Sadly many alternate names are highly overloaded > > already > > > (think "carrier" for instance, or "bus"). I like the term > > "train" > > > because of the association with a schedule, but that's just me. > > > >> > > > >> Same goes actually for the complex path that we build. That > > > complex path can be an elongated DODAG with multiple PREOF > > points. > > > Usual terms like "circuit" or "path" fail to capture that > > > complexity. 6TiSCH found the term "Track" to refer to it. > > > >> > > > >> Would you push that discussion to the ML? > > > >> > > > >> Take care, > > > >> > > > >> Pascal > > > >> > > > >>> -----Original Message----- > > > >>> From: Lou Berger <lberger@labn.net > > <mailto:lberger@labn.net> <mailto:lberger@labn.net > > <mailto:lberger@labn.net>>> > > > >>> Sent: mardi 20 novembre 2018 13:11 > > > >>> To: Scharf, Michael <Michael.Scharf@hs-esslingen.de > > <mailto:Michael.Scharf@hs-esslingen.de> > > > <mailto:Michael.Scharf@hs-esslingen.de > > <mailto:Michael.Scharf@hs-esslingen.de>>> > > > >>> Cc: tsv-art@ietf.org <mailto:tsv-art@ietf.org> > > <mailto:tsv-art@ietf.org <mailto:tsv-art@ietf.org>>; > > > detnet@ietf.org <mailto:detnet@ietf.org> <mailto:detnet@ietf.org > > <mailto:detnet@ietf.org>>; draft-ietf-detnet- > > > >>> architecture.all@ietf.org > > <mailto:architecture.all@ietf.org> > > <mailto:architecture.all@ietf.org <mailto:architecture.all@ietf.org > >> > > > >>> Subject: Re: [Detnet] Tsvart last call review of > > > draft-ietf-detnet-architecture-08 > > > >>> > > > >>> Michael, > > > >>> > > > >>> I think we're getting somewhere and identifying where we > > have > > > disconnects > > > >>> and what may (and what may not) need to change in the > > > document. My > > > >>> takeaways are: > > > >>> > > > >>> - The document needs a good 'scrub' of the congestion > > related > > > references to > > > >>> ensure that the document only makes statements on what is > > > actually done > > > >>> within a DetNet and the relationship with transport > > protocols > > > that use detnet > > > >>> (which are in fact outside the scope of the DetNet WG). > > I'll > > > work with the > > > >>> authors and WG on this -- I see this change as > > important, but > > > editorial in > > > >>> nature. > > > >>> > > > >>> - We have a perception issue with at least one member of > the > > > TSV area on the > > > >>> meaning and more importantly, implication, of the term > > "DetNet > > > >>> *Transport* sub-layer". While I don't disagree that a good > > > portion of the IETF > > > >>> thinks transport protocol (UDP/TCP) when they hear > > "transport" > > > >>> there are plenty others, particularly in the routing > > area, who > > > understand that > > > >>> "transport" can refer to Transport Networks. And Transport > > > Network is a well > > > >>> understood general industry term. The IETF even has a > > bunch of > > > RFCs that > > > >>> relate to Transport networks. This said, I think it > > > reasonable to go back to the > > > >>> DetNet WG and discuss changing the name of the "DetNet > > > Transport sub- > > > >>> layer" to avoid the word "transport". -- BTW we made a > > > parallel change in > > > >>> the TEAS WG when producing RFC8453. > > > >>> > > > >>> See below for detail response in-line. > > > >>> > > > >>> On 11/19/2018 5:15 PM, Scharf, Michael wrote: > > > >>>> Lou, > > > >>>> > > > >>>>> -- > > > >>>>> I wanted to take a step back from the multiple > discussions > > > that were > > > >>>>> spawned by your review -- from a doc shepherd > perspective, > > > and see > > > >>>>> where we are. I know that the authors have sent a -09 > > > version that > > > >>>>> addresses some, but not all issues. > > > >>>>> > > > >>>>> From the exchanges I've seen, I think the key > > remaining > > > issues are > > > >>>>> related to: > > > >>>>> > > > >>>>> (a) possibly introduction of congestion in the general > > > internet if > > > >>>>> packets were somehow to escape a detnet domain. The > > source > > > of this > > > >>>>> congestion would be inelastic traffic using DetNet or > > due to > > > >>>>> congestion loss that is masked by PREOF. > > > >>>> These are two major issues that need to be addressed. Note > > > that it may not > > > >>> be sufficient just to add a section on operational and > > deployment > > > >>> considerations. Also the existing text in the document will > > > need to get aligned > > > >>> to normative guidance on how to avoid a congestion > collapse. > > > >>>> In -09, one example would be Section 3.1. "Primary goals > > > defining the > > > >>> DetNet QoS" > > > >>>> Congestion protection operates by allocating > > resources > > > along the path > > > >>>> of a DetNet flow, e.g., buffer space or link > > > bandwidth. Congestion > > > >>>> protection greatly reduces, or even eliminates > > > entirely, packet loss > > > >>>> due to output packet congestion within the > > network, but > > > it can only > > > >>>> be supplied to a DetNet flow that is limited at the > > > source to a > > > >>>> maximum packet size and transmission rate. Note > that > > > congestion > > > >>>> protection provided via congestion detection and > > > notification is > > > >>>> explicitly excluded from consideration in DetNet, > > as it > > > serves a > > > >>>> different set of applications. > > > >>>> At least the last sentence would contradict a better > > > discussion of congestion > > > >>> in the document. For instance, it could just be removed. In > > > any case, the > > > >>> current wording in the last sentence is not correct, as the > > > IETF term for what is > > > >>> described in the last sentence is "congestion control". > > > >>>> Another example would be Section 3.2.1.1. "Eliminate > > > congestion loss" > > > >>>> > > > >>>> The primary means by which DetNet achieves its QoS > > > assurances is to > > > >>>> reduce, or even completely eliminate, congestion > > within > > > a DetNet node > > > >>>> as a cause of packet loss. This can be achieved only > > > by the > > > >>>> provision of sufficient buffer storage at each node > > > through the > > > >>>> network to ensure that no packets are dropped due > > to a > > > lack of buffer > > > >>>> storage. Note that a DetNet flow cannot be > > throttled, > > > i.e., its > > > >>>> transmission rate cannot be reduced via explicit > > congestion > > > >>>> notification. > > > >>>> > > > >>>> This section IMHO has to include a discussion of what > > happens > > > in the (not > > > >>> expected) case that packets get dropped or that ECN > > marks are > > > received. It is > > > >>> understood that this would not happen in normal > > operation of a > > > DetNet > > > >>> network, but I believe just considering the error-free > > > operation of a DetNet > > > >>> network is not sufficient for this document. At least > > for the > > > risk of traffic that > > > >>> may escape from a DetNet network is inherently not > > sufficient > > > to assume that > > > >>> the DetNet network is always error-free. > > > >>> > > > >>> I think these are examples of text that needs to be > > cleanup up > > > and to > > > >>> delineate what is done with a DetNet. > > > >>> > > > >>> > > > >>>> As a result, addressing my concerns will most likely > > require > > > editing several > > > >>> parts of the document. > > > >>>> In addition, I'd like to emphasize that my review > > comment "It > > > is surprising > > > >>> that there is hardly any discussion on network > > robustness and > > > safety" > > > >>> > > > >>> I have no idea what you mean by safety here. Can you > > elaborate. > > > >>> > > > >>> > > > >>>> covers more than just inelastic traffic that escapes from > a > > > DetNet network > > > >>> and masking of packet loss. Given that DetNet traffic may > be > > > extremely critical > > > >>> traffic, I really wonder why the document doesn't emphasize > > > more the > > > >>> required robustness against failures *inside* the DetNet > > > network as well as > > > >>> counter-measures. But this is something the WG needs to > > > decide. As TSV-ART > > > >>> reviewer, I will be fine if the document clearly > > describes how > > > the impact of > > > >>> failures will be isolated inside the DetNet network and > will > > > not put the general > > > >>> Internet at risk. > > > >>> > > > >>> I agree - I think, the document should be clear on it's > > scope and > > > >>> relationship to general internet usage. > > > >>> > > > >>> > > > >>>>> (b) The use of the term 'transport' in DetNet to refer to > > > what is > > > >>>>> basically a Traffic Engineered sub-network layer, such > > as is > > > provided > > > >>>>> with MPLS-TE or Optical Transport Networks. > > > >>>> In the Internet architecture, the term 'transport' > > refers to > > > Internet transport > > > >>> protocols. I doubt that the document can avoid > > discussing the > > > implications of > > > >>> and interactions with Internet transport protocols such > > as UDP > > > or TCP. As a > > > >>> result, I disagree that the document can use the term > > > 'transport' to refer to > > > >>> traffic engineered sub-network layers. > > > >>> > > > >>> I think this is covered by my comment above. > > > >>> > > > >>> > > > >>>> From a TSV-ART point of view, the document can > > either only > > > use the term > > > >>> "transport" for Internet transport protocols and use > another > > > term for sub- > > > >>> network layers (as handled in the *routing* area of the > > IETF), > > > or the document > > > >>> has to clearly distinguish between the Internet transport > > > layer and other uses > > > >>> of the term "transport" and explain the overlap. I > > believe the > > > former would be > > > >>> less confusing, but I will leave it up to the TSV ADs to > > > discuss terminology > > > >>> overlap in the IESG. As TSV-ART reviewer I insist that the > > > document uses the > > > >>> terms "transport layer" and "transport protocol" only when > > > referring to the > > > >>> Internet transport layer. > > > >>> > > > >>> I'm personally okay with a name change and even willing to > > > push this > > > >>> discussion within the WG, but as said above, "Transport > > > Network" is a > > > >>> generally understood industry term that is also used in > RFCs > > > -- so we'll > > > >>> have to see what where WG consensus ends up. > > > >>> > > > >>>>> Do you have any other issues that that are critical to be > > > addressed > > > >>>>> before this work moves forward? If so which? > > > >>>> Regarding Section 4.4 I have already deferred the > > discussion > > > to the IESG. The > > > >>> TSV-ART review comment is that the IESG needs to carefully > > > look at the > > > >>> concepts, terminology, and references in section 4.4. > > > >>>> Regarding my other comments, I acknowledge that -09 is > > a step > > > forward. But > > > >>> given the cross-dependencies e.g. regarding terminology and > > > definitions, I will > > > >>> need to read the text completely once there is a > > proposal how > > > to address my > > > >>> review. As noted in my review, I believe the document > > must use > > > terminology > > > >>> clearly and consistently. As example, a statement in -09 > > such > > > as "Network > > > >>> nodes supporting DetNet flows have to implement some of > > the DetNet > > > >>> capabilities (not necessarily all) in order to treat DetNet > > > flows such that their > > > >>> QoS requirements are met" is IMHO too vague. But in such > > cases > > > it depends > > > >>> whether there is precise normative guidance elsewhere. And > > > this requires > > > >>> looking at the text as a whole. > > > >>> > > > >>> I think the next steps lie with me and the WG. We'll let > you > > > know once > > > >>> there is a new version. Of course, you can also > > contribute to > > > the WG > > > >>> discussion on the topic. > > > >>> > > > >>> Thanks, > > > >>> > > > >>> Lou > > > >>> > > > >>>> Best regards > > > >>>> > > > >>>> Michael > > > >>>> > > > >>>> > > > >>>> > > > >>>>> Thank you, > > > >>>>> > > > >>>>> Lou > > > >>>>> > > > >>>>> On 9/28/2018 6:24 PM, Michael Scharf wrote: > > > >>>>>> Reviewer: Michael Scharf > > > >>>>>> Review result: Ready with Issues > > > >>>>>> > > > >>>>>> The document "Deterministic Networking Architecture" > > > >>>>>> (draft-ietf-detnet-architecture-08) defines an overall > > > framework for > > > >>>>>> Deterministic Networking. > > > >>>>>> > > > >>>>>> As TSV-ART reviewer, I believe that this document has > > issues as > > > >>>>> detailed below. > > > >>>>>> Michael > > > >>>>>> > > > >>>>>> Major issues: > > > >>>>>> > > > >>>>>> * It seems that DetNet cannot easily be deployed in the > > > Internet > > > >>>>> without > > > >>>>>> additional means. Thus, for a baseline document, one > > could > > > expect > > > >>>>> some > > > >>>>>> explanation on the requirements of deploying DetNet in a > > > network. > > > >>>>> DetNet > > > >>>>>> basically requires support in (almost) all network > > devices > > > >>>>> transporting DetNet > > > >>>>>> traffic. That assumption should be explicitly spelt out > > > early in the > > > >>>>> document, > > > >>>>>> e.g., in the introduction. There also needs to be an > > explicit > > > >>>>> discussion of the > > > >>>>>> implications if not the whole network is aware of or > > > supports DetNet. > > > >>>>> There is > > > >>>>>> some text in Section 4.2.2 and Section 4.3.3, but I > > believe > > > >>>>> additional explicit > > > >>>>>> discussion is needed at a prominant place. For instance, > > > can use of > > > >>>>> DetNet do > > > >>>>>> harm to parts of a network not supporting DetNet? As > > a side > > > note, > > > >>>>> when TCPM > > > >>>>>> published RFC 8257, the following disclaimer was added: > > > "DCTCP, as > > > >>>>> described in > > > >>>>>> this specification, is applicable to deployments in > > controlled > > > >>>>> environments > > > >>>>>> like data centers, but it must not be deployed over > > the public > > > >>>>> Internet without > > > >>>>>> additional measures." I wonder if a similar disclaimer > is > > > needed for > > > >>>>> DetNet. If > > > >>>>>> there is an implicit assumption that DetNet will be > > used in > > > >>>>> homogenous > > > >>>>>> environments with mostly DetNet-aware devices within > > the same > > > >>>>> organization, > > > >>>>>> such an assumption should be made explicit. > > > >>>>>> > > > >>>>>> * It is surprising that there is hardly any discussion > on > > > network > > > >>>>> robustness > > > >>>>>> and safety; this probably also relates to security. For > > > instance, > > > >>>>>> misconfiguration or errors of functions performing > packet > > > replication > > > >>>>> could > > > >>>>>> severely and permantly congest a network and cause harm. > > > How does the > > > >>>>> DetNet > > > >>>>>> architecture ensure that a network stays fully > > operational > > > e.g. if > > > >>>>> the topology > > > >>>>>> changes or there are equipment failures? Probably > > this can > > > be solved > > > >>>>> by > > > >>>>>> implementations (e.g., dynamic control plane), but > > why are > > > >>>>> corresponding > > > >>>>>> requirements not spelt out? Section 3.3.2 speculates > that > > > filters and > > > >>>>> policers > > > >>>>>> can help, and that may be true, but that probably > > still assumes > > > >>>>> consistently > > > >>>>>> and correctly configured (and well-behaving) devices. > And > > > Section > > > >>>>> 3.3.2 is > > > >>>>>> vague and mentions a "infinite variety of possible > > > failures" without > > > >>>>> stating > > > >>>>>> any requirements or recommendations. There may be > further > > > solutions, > > > >>>>> such as > > > >>>>>> circuit breakers and the like. Why are such topics not > > > discussed? > > > >>>>>> > > > >>>>>> * Somewhat related, the document only looks at impact of > > > failures to > > > >>>>> the QoS of > > > >>>>>> DetNet traffic. What is missing is a discussion how to > > > protect non- > > > >>>>> DetNet parts > > > >>>>>> of a network from any harm caused by DetNet mechanisms. > > > Solutions to > > > >>>>> this > > > >>>>>> probably exist. But why is the impact on non-DetNet > > traffic > > > (e.g., in > > > >>>>> case of > > > >>>>>> topology changes or failures of DetNet functions) not > > > discussed at > > > >>>>> all in the > > > >>>>>> document? > > > >>>>>> > > > >>>>>> * Regarding security, an architecture like DetNet > > probably > > > requires > > > >>>>> that only > > > >>>>>> authenticated and authorized end systems have access > > to the > > > data > > > >>>>> plane. The > > > >>>>>> security considerations only briefly mention the control > > > aspect ("the > > > >>>>>> authentication and authorization of the controlling > > systems"). > > > >>>>>> > > > >>>>>> * For an architecture document, the lack of clarity and > > > consistency > > > >>>>> regarding > > > >>>>>> terminology is concerning. This specifically applies > > to the > > > case of > > > >>>>> incomplete > > > >>>>>> networks (as per Section 4.2.2 and 4.3.3) that > > include "DetNet- > > > >>>>> unaware nodes". > > > >>>>>> The document introduces terms such as "DetNet > > intermediate > > > nodes" but > > > >>>>> then > > > >>>>>> repeatedly uses generic terms such as "node" or "hop" > > that may > > > >>>>> include > > > >>>>>> DetNet-unaware nodes. For instance, for incomplete > > networks, a > > > >>>>> sentence such as > > > >>>>>> "The primary means by which DetNet achieves its QoS > > > assurances is to > > > >>>>> reduce, or > > > >>>>>> even completely eliminate, congestion within a node as a > > > cause of > > > >>>>> packet loss" > > > >>>>>> seems to only apply to "DetNet transit nodes" but not > > > "DetNet-unaware > > > >>>>> nodes". > > > >>>>>> Similar ambiguity exist for other use of the terms "hop" > > > and "node", > > > >>>>> which may > > > >>>>>> or may not include DetNet-unaware nodes. It is > > unclear why the > > > >>>>> document does > > > >>>>>> not consistently use the terminology introduced in > > Section > > > 2.1 in all > > > >>>>> sections > > > >>>>>> and clearly distinguishes cases with and without DetNet > > > support. > > > >>>>>> > > > >>>>>> * Section 4.4 refers to RFC 7426, which is an > > informational > > > RFC on > > > >>>>> IRTF stream, > > > >>>>>> and the document uses the concepts introduced there > > (e.g., > > > "planes"). > > > >>>>> This is > > > >>>>>> very confusing. First, an IETF Proposed Standard should > > > probably > > > >>>>> refer to > > > >>>>>> documents having IETF consensus. An example would be RFC > > > 7491, albeit > > > >>>>> there is > > > >>>>>> other related work as well, e.g., in the TEAS WG. > Second, > > > Section 4.4 > > > >>>>> is by and > > > >>>>>> large decoupled from the rest of the document and not > > > specific to > > > >>>>> DetNet. > > > >>>>>> Neither do other sections of the document refer to > > the concepts > > > >>>>> introduced in > > > >>>>>> Section 4.4, nor does Section 4.4 use the DetNet > > terminology or > > > >>>>> discuss > > > >>>>>> applicability to DetNet. Section 4.4 even mentions > > > explicitly at the > > > >>>>> end that > > > >>>>>> it discusses aspects that are orthogonal to the DetNet > > > architecture. > > > >>>>> It is not > > > >>>>>> at all clear why Section 4.4 is in this document. > Section > > > 4.4 could > > > >>>>> be removed > > > >>>>>> from the document without impacting the rest of the > > document. > > > >>>>>> > > > >>>>>> Minor issues: > > > >>>>>> > > > >>>>>> * Terminology "DetNet transport layer" > > > >>>>>> > > > >>>>>> The term "transport layer" has a well-defined > > meaning > > > in the IETF, > > > >>>>> e.g. > > > >>>>>> originating from RFC 1122. While "transport" > > and e.g. > > > "transport > > > >>>>> network" is > > > >>>>>> used in the IETF for different technologies in > > > different areas, I > > > >>>>> think the > > > >>>>>> term "transport layer" is typically understood to > > > refer to > > > >>>>> transport > > > >>>>>> protocols such as TCP and UDP. As such, I > > personally > > > find the term > > > >>>>> "DetNet > > > >>>>>> transport layer" misleading and confusing. The > > > confusion is easy > > > >>>>> to see e.g. > > > >>>>>> in Figure 4, where UDP (which is a transport > > protocol > > > as per RFC > > > >>>>> 1122) sits > > > >>>>>> on top of "transport". > > > >>>>>> > > > >>>>>> Based on the document it also may be > > > solution/implementation > > > >>>>> specific whether > > > >>>>>> the "DetNet transport layer" is actually a > separate > > > protocol layer > > > >>>>> compared > > > >>>>>> to the "DetNet service layer". Thus it is not > clear > > > to me why the > > > >>>>> word > > > >>>>>> "layer" has to be used, specifically in > combination > > > "transport > > > >>>>> layer". > > > >>>>>> To me as, the word "transport layer" (and > > "transport > > > protocol") > > > >>>>> should be > > > >>>>>> used for protocols defined in TSV area, consistent > > > with RFC 1122. > > > >>>>> But this is > > > >>>>>> probably a question to be sorted out by the IESG. > > > >>>>>> > > > >>>>>> * Page 9 > > > >>>>>> > > > >>>>>> A DetNet node may have other resources requiring > > > allocation > > > >>>>> and/or > > > >>>>>> scheduling, > > > >>>>>> > > > >>>>>> This is just one of several examples for > > inconsistent > > > use of > > > >>>>> terminology. > > > >>>>>> What is a "DetNet node"? That term is not > > introduced > > > in Section > > > >>>>> 2.1 > > > >>>>>> * Page 14 > > > >>>>>> > > > >>>>>> A DetNet network supports the dedication of a > high > > > proportion > > > >>>>> (e.g. > > > >>>>>> 75%) of the network bandwidth to DetNet flows. > > > >>>>>> > > > >>>>>> The 75% value is not reasoned. What prevents using > > > 99% of the > > > >>>>> bandwidth for > > > >>>>>> DetNet traffic? > > > >>>>>> > > > >>>>>> * Page 15: Figure 2 > > > >>>>>> > > > >>>>>> If the term "transport layer" cannot be > > avoided, the > > > labels in > > > >>>>> this figure > > > >>>>>> should at least be expanded to "DetNet > > transport layer". > > > >>>>>> > > > >>>>>> * Page 18: Figure 4 > > > >>>>>> > > > >>>>>> As already mentioned earlier, Figure 4 is > > confusing. > > > UDP is a > > > >>>>> transport > > > >>>>>> protocol. If the term "transport" cannot be > > avoided, > > > the labels in > > > >>>>> this > > > >>>>>> figure should at least be expanded to "DetNet > > transport". > > > >>>>>> > > > >>>>>> * Page 23 > > > >>>>>> > > > >>>>>> If the source transmits less data than this limit > > > >>>>>> allows, the unused resource such as link > bandwidth > > > can be made > > > >>>>>> available by the system to non-DetNet packets. > > > >>>>>> > > > >>>>>> Could there be additional requirements on the > > use of > > > unused > > > >>>>> resources by > > > >>>>>> non-DetNet packets, e.g., regarding preemption? > > I am just > > > >>>>> wondering... If > > > >>>>>> that was possible, a statement like "... can be > > made > > > available by > > > >>>>> the system > > > >>>>>> to non-DetNet packets as long as all guarantees > are > > > fulfilled" > > > >>>>> would be on > > > >>>>>> the safe side, no? > > > >>>>>> > > > >>>>>> * Page 27: > > > >>>>>> > > > >>>>>> DetNet achieves congestion protection and bounded > > > delivery > > > >>>>> latency by > > > >>>>>> reserving bandwidth and buffer resources at every > > > hop along the > > > >>>>> path > > > >>>>>> of the DetNet flow. > > > >>>>>> > > > >>>>>> Why does this sentence use the word "hop"? As > > far as > > > I understand, > > > >>>>> in DetNet > > > >>>>>> bandwidth and buffer resources are reserved in > each > > > DetNet > > > >>>>> intermediate node. > > > >>>>>> If there were hops over IP routers not being > DetNet > > > intermediate > > > >>>>> nodes, no > > > >>>>>> resources would be reserved there. As per Section > > > 4.3.3, it is > > > >>>>> possible to > > > >>>>>> deploy DetNet this way. And obviously there can be > > > resource > > > >>>>> bottlenecks below > > > >>>>>> IP, on devices that are not routers... So does > > "hop" > > > here refer to > > > >>>>> IP router > > > >>>>>> hops or also to devices not processing IP (or > > IP/MPLS)? > > > >>>>>> > > > >>>>>> * Page 27: > > > >>>>>> > > > >>>>>> Standard queuing and transmission selection > > > algorithms allow a > > > >>>>>> central controller to compute the latency > > > contribution of each > > > >>>>>> transit node to the end-to-end latency, ... > > > >>>>>> > > > >>>>>> The text does not explain why a _central_ > > controller > > > is needed for > > > >>>>> this > > > >>>>>> computation. Why would a distributed control plane > > > not be able to > > > >>>>> realize > > > >>>>>> this computation. Isn't this > > implementation-specific? > > > >>>>>> > > > >>>>>> * Page 32 > > > >>>>>> > > > >>>>>> To somebody who is not deeply familiar with > > DetNet, it is > > > >>>>> impossible to parse > > > >>>>>> the description of the examples in Section > > 4.7.3. For > > > instance, > > > >>>>> "VID + > > > >>>>>> multicast MAC address" is not introduced. I think > > > this example > > > >>>>> must be > > > >>>>>> expaned with additional context and explanation > > to be > > > useful to > > > >>>>> readers. > > > >>>>>> * Page 34 > > > >>>>>> > > > >>>>>> There are three classes of information that a > > > central controller > > > >>>>> or > > > >>>>>> distributed control plane needs to know that can > > > only be obtained > > > >>>>>> from the end systems and/or nodes in the network. > > > >>>>>> > > > >>>>>> Wouldn't it be sufficient to state "Provisioning > of > > > DetNet > > > >>>>> requires knowledge > > > >>>>>> about ...". Does it matter in this context > > whether the > > > >>>>> provisioning is done > > > >>>>>> by a central controller or a distributed control > > > plane? For > > > >>>>> instance, could > > > >>>>>> the same paragraph also apply to a network that > > uses > > > _multiple_ > > > >>>>> central > > > >>>>>> controllers, or hybrid combinations of central > > > controllers and > > > >>>>> distributed > > > >>>>>> control planes? In general, an architecture > > document > > > should be > > > >>>>> agnostic to > > > >>>>>> implementation aspects unless there is a specific > > > need. In this > > > >>>>> specific > > > >>>>>> case, I fail to see a need to discuss the > > realization > > > of the > > > >>>>> control plane of > > > >>>>>> a network. > > > >>>>>> > > > >>>>>> Editorial nits: > > > >>>>>> > > > >>>>>> * Page 9: > > > >>>>>> > > > >>>>>> The low-level mechanisms described in Section 4.5 > > > provide the > > > >>>>>> necessary regulation of transmissions by an end > > > system or > > > >>>>>> intermediate node to provide congestion > > protection. The > > > >>>>> allocation > > > >>>>>> of the bandwidth and buffers for a DetNet flow > > requires > > > >>>>> provisioning > > > >>>>>> A DetNet node may have other resources requiring > > > allocation > > > >>>>> and/or > > > >>>>>> scheduling, that might otherwise be > > over-subscribed > > > and trigger > > > >>>>> the > > > >>>>>> rejection of a reservation. > > > >>>>>> > > > >>>>>> Probably a full stop is missing after > > "provisioning". > > > >>>>>> > > > >>>>>> * Page 11: "... along separate (disjoint non-SRLG) > > paths ..." > > > >>>>>> > > > >>>>>> I find this confusing. I would understand e.g. > > "along > > > separate > > > >>>>>> (SRLG-disjoint) paths". > > > >>>>>> > > > >>>>>> * Page 34: > > > >>>>>> > > > >>>>>> When using a peer- > > > >>>>>> to-peer control plane, some of this > > information may > > > be required > > > >>>>> by a > > > >>>>>> system's neighbors in the network. > > > >>>>>> > > > >>>>>> Would "acquired" be a better term? > > > >>>>>> > > > >>>>>> * Page 34: > > > >>>>>> > > > >>>>>> o The identity of the system's neighbors, and > the > > > >>>>> characteristics of > > > >>>>>> the link(s) between the systems, including the > > > length (in > > > >>>>>> nanoseconds) of the link(s). > > > >>>>>> > > > >>>>>> "Latency" or "delay" would probably be a better > > terms > > > if the value > > > >>>>> is > > > >>>>>> measured in nanoseconds. > > > >>>>>> > > > >>>>>> * Page 35: > > > >>>>>> > > > >>>>>> DetNet is provides a Quality of Service (QoS), > and > > > as such, does > > > >>>>> not > > > >>>>>> directly raise any new privacy considerations. > > > >>>>>> > > > >>>>>> Broken sentence > > > >>>>>> > > > >>>>>> * Please expand acronyms on first use (e.g., OTN) > > > >>>>>> > > > >>>>>> > > > >>>> _______________________________________________ > > > >>>> detnet mailing list > > > >>>> detnet@ietf.org <mailto:detnet@ietf.org> > > <mailto:detnet@ietf.org <mailto:detnet@ietf.org>> > > > >>>> https://www.ietf.org/mailman/listinfo/detnet > > > > > > _______________________________________________ > > > detnet mailing list > > > detnet@ietf.org <mailto:detnet@ietf.org> <mailto:detnet@ietf.org > > <mailto:detnet@ietf.org>> > > > https://www.ietf.org/mailman/listinfo/detnet > > > > > >
- [Detnet] Tsvart last call review of draft-ietf-de… Michael Scharf
- Re: [Detnet] Tsvart last call review of draft-iet… János Farkas
- Re: [Detnet] Tsvart last call review of draft-iet… Scharf, Michael
- Re: [Detnet] Tsvart last call review of draft-iet… Black, David
- Re: [Detnet] Tsvart last call review of draft-iet… Lou Berger
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Scharf, Michael
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Black, David
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Black, David
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Lou Berger
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Scharf, Michael
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Lou Berger
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Toerless Eckert
- [Detnet] Fwd: Re: Tsvart last call review of draf… János Farkas
- Re: [Detnet] Fwd: Re: Tsvart last call review of … Lou Berger
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Scharf, Michael
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Toerless Eckert
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Scharf, Michael
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Toerless Eckert
- Re: [Detnet] Tsvart last call review of draft-iet… Lou Berger
- Re: [Detnet] Tsvart last call review of draft-iet… Scharf, Michael
- Re: [Detnet] Tsvart last call review of draft-iet… Lou Berger
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Scharf, Michael
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Black, David
- Re: [Detnet] Tsvart last call review of draft-iet… Pascal Thubert (pthubert)
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Lou Berger
- Re: [Detnet] Transport sub-layer name change (Was… Pascal Thubert (pthubert)
- Re: [Detnet] Transport sub-layer name change (Was… Grossman, Ethan A.
- [Detnet] Transport sub-layer name change (Was Re:… Lou Berger
- Re: [Detnet] Transport sub-layer name change (Was… Andrew G. Malis
- Re: [Detnet] Transport sub-layer name change (Was… Lou Berger
- Re: [Detnet] Transport sub-layer name change (Was… Toerless Eckert
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Scharf, Michael
- Re: [Detnet] Transport sub-layer name change (Was… Lou Berger
- Re: [Detnet] Transport sub-layer name change (Was… Mach Chen
- Re: [Detnet] Transport sub-layer name change (Was… Pascal Thubert (pthubert)
- Re: [Detnet] Transport sub-layer name change (Was… Loa Andersson
- Re: [Detnet] Transport sub-layer name change (Was… Toerless Eckert
- Re: [Detnet] Transport sub-layer name change (Was… Lou Berger
- Re: [Detnet] Transport sub-layer name change (Was… Toerless Eckert
- Re: [Detnet] Transport sub-layer name change (Was… Norman Finn
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Norman Finn
- Re: [Detnet] [Tsv-art] Tsvart last call review of… Scharf, Michael
- Re: [Detnet] Transport sub-layer name change (Was… János Farkas
- Re: [Detnet] Transport sub-layer name change (Was… Lou Berger
- Re: [Detnet] Transport sub-layer name change (Was… Andrew G. Malis
- Re: [Detnet] Transport sub-layer name change (Was… Greg Mirsky
- Re: [Detnet] Transport sub-layer name change (Was… Loa Andersson
- Re: [Detnet] Transport sub-layer name change (Was… S.V.R.Anand
- Re: [Detnet] Transport sub-layer name change (Was… Pascal Thubert (pthubert)
- Re: [Detnet] Transport sub-layer name change (Was… qiangli (D)
- Re: [Detnet] Transport sub-layer name change (Was… Balázs Varga A
- Re: [Detnet] Transport sub-layer name change (Was… Loa Andersson
- Re: [Detnet] Transport sub-layer name change (Was… Andrew G. Malis
- [Detnet] Congestion Protection name change (was: … János Farkas
- Re: [Detnet] Congestion Protection name change (w… Pascal Thubert (pthubert)
- Re: [Detnet] Congestion Protection name change (w… Andrew G. Malis
- Re: [Detnet] Congestion Protection name change (w… Lou Berger
- Re: [Detnet] Congestion Protection name change János Farkas
- Re: [Detnet] Congestion Protection name change Black, David
- Re: [Detnet] Congestion Protection name change Pascal Thubert (pthubert)
- Re: [Detnet] Congestion Protection name change (w… qiangli (D)
- Re: [Detnet] Congestion Protection name change qiangli (D)
- Re: [Detnet] Congestion Protection name change Balázs Varga A
- Re: [Detnet] Congestion Protection name change Lou Berger
- Re: [Detnet] Congestion Protection name change Lou Berger
- Re: [Detnet] Congestion Protection name change Pascal Thubert (pthubert)
- Re: [Detnet] Congestion Protection name change Lou Berger
- Re: [Detnet] Transport sub-layer name change (Was… Stewart Bryant
- Re: [Detnet] Transport sub-layer name change (Was… Lou Berger
- Re: [Detnet] Transport sub-layer name change (Was… Andrew G. Malis
- Re: [Detnet] Congestion Protection name change Lou Berger
- Re: [Detnet] Transport sub-layer name change (Was… Lou Berger
- Re: [Detnet] Transport sub-layer name change (Was… Andrew G. Malis
- Re: [Detnet] Congestion Protection name change Andrew G. Malis
- Re: [Detnet] Congestion Protection name change John E Drake
- Re: [Detnet] Transport sub-layer name change (Was… Andrew G. Malis
- Re: [Detnet] Transport sub-layer name change (Was… Lou Berger
- Re: [Detnet] [Tsv-art] Tsvart last call review of… János Farkas