Re: [Pce] Poll for adoption: draft-dhody-pce-stateful-pce-auto-bandwidth-09
"Adrian Farrel" <adrian@olddog.co.uk> Wed, 18 January 2017 20:14 UTC
Return-Path: <adrian@olddog.co.uk>
X-Original-To: pce@ietfa.amsl.com
Delivered-To: pce@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 0564D12994F; Wed, 18 Jan 2017 12:14:28 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.619
X-Spam-Level:
X-Spam-Status: No, score=-2.619 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01] 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 REFhd0IkEugH; Wed, 18 Jan 2017 12:14:24 -0800 (PST)
Received: from asmtp4.iomartmail.com (asmtp4.iomartmail.com [62.128.201.175]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 0B134129967; Wed, 18 Jan 2017 12:14:23 -0800 (PST)
Received: from asmtp4.iomartmail.com (localhost.localdomain [127.0.0.1]) by asmtp4.iomartmail.com (8.13.8/8.13.8) with ESMTP id v0IKELbL008566; Wed, 18 Jan 2017 20:14:21 GMT
Received: from 950129200 (westford-nat.juniper.net [66.129.232.2]) (authenticated bits=0) by asmtp4.iomartmail.com (8.13.8/8.13.8) with ESMTP id v0IKEIJ4008504 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NO); Wed, 18 Jan 2017 20:14:19 GMT
From: Adrian Farrel <adrian@olddog.co.uk>
To: 'Jonathan Hardwick' <Jonathan.Hardwick@metaswitch.com>, pce@ietf.org
References: <BY2PR0201MB191078869D7F31052330053284600@BY2PR0201MB1910.namprd02.prod.outlook.com>
In-Reply-To: <BY2PR0201MB191078869D7F31052330053284600@BY2PR0201MB1910.namprd02.prod.outlook.com>
Date: Wed, 18 Jan 2017 20:14:21 -0000
Message-ID: <04d801d271c7$75a51770$60ef4650$@olddog.co.uk>
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="----=_NextPart_000_04D9_01D271C7.75AA2080"
X-Mailer: Microsoft Outlook 14.0
Thread-Index: AQIr/eg1Q9mZk8qgpXnDhlnKP/1QeKCLKcTg
Content-Language: en-gb
X-TM-AS-MML: disable
X-TM-AS-Product-Ver: IMSS-7.1.0.1679-8.0.0.1202-22832.002
X-TM-AS-Result: No--11.930-10.0-31-10
X-imss-scan-details: No--11.930-10.0-31-10
X-TMASE-MatchedRID: 8HTFlOrbAtHaOWCt37RI5txajlW+zwxC6Jj6zYvfFARq4coTktrGX3iC e8dVoQXoem7Q0/BfQ0idtXuGCMK7bi/aTczbsnfWsyNb+yeIRApAq6/y5AEOOjcS3AT+4zzmM+p +NpswZmqJQNchOWKA0AFpW8YpqUTnTBoKJVzWO8JbuDP8ZuCmXuPmXK6rwg5Bq8z7POX8FJOGkY lEJW/HpPjtCmIiy79jK60WoPcsLkcsYcQhsLi5b9/wYmMFcJSIzUNrsfquv4gwp/4s3hUlGDcuo 3EoNtwLPdJs51vPe8klmxw7mfzDLjIis6myWdj62MMmxTWvrZu/yN2q8U674tqCxkzSpW/X3O10 Rw/K4HToveWDnoc1EMrwwM67bcRVBVwP6b8+JkgdxBAG5/hkW/ltVCXwDZiOVL6geaPy6nNnLab I67VZfJx4qSW9CqMu7yN7I89ZnPWkOIY39zkh2AArNgt5xpQYXEjKf9fhKae638ZUY6gSd435bh tr3DJiRcH8vHuusswyhzimQryyp03NdyQQY/k0020eWoALA9dezmeoa8MJ8yNGK7UC7ElMa3I1H yduQXReZvbG18jEQAIFofE49tCvMRXV8lvz/l3XIwmz2YEJxVHB9PagRph0HGRbGDv0rgiI+yd4 8zjY3fVqKYoVu7XrJcCLAhZvOaLVBhnhEFJQQ70dPFETpBAHecvjbu/xDjqKvtIv3yXJCf3tbKD JQoHTTRlO4YqBQoetx+zrfgtm8e+9lv9tq/TYlVHM/F6YkvQUOnkJcyxUv8fHH/M5FHNaEWXAmF VxJU77zAFKdlvdc0LaCyddTYfYRF8J0whn5t2eAiCmPx4NwGmRqNBHmBvevqq8s2MNhPDB6hM9Z 2+oTAgba0jhlfsrywk6UeWv0A+6GYyzFQwovoXG3TnjfylwRpFPVAZ/ON6RE3vvGIUle4YDLCi3 jHJb4VirBQgxPzecGB6i9KnSVCQTZWLe2jFG5Qfb5tjQgYQ=
Archived-At: <https://mailarchive.ietf.org/arch/msg/pce/Ff979q-XFmgGWhYSC9y9M0VebbQ>
Cc: draft-dhody-pce-stateful-pce-auto-bandwidth@ietf.org, pce-chairs@ietf.org
Subject: Re: [Pce] Poll for adoption: draft-dhody-pce-stateful-pce-auto-bandwidth-09
X-BeenThere: pce@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
Reply-To: adrian@olddog.co.uk
List-Id: Path Computation Element <pce.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/pce>, <mailto:pce-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/pce/>
List-Post: <mailto:pce@ietf.org>
List-Help: <mailto:pce-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/pce>, <mailto:pce-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 18 Jan 2017 20:14:28 -0000
Hi Jon, chairs, I think this is something we should be working on and I think that this draft will be a reasonable starting point although I do have some issues for discussion. I think we can handle the issues at any time (including after adoption). Thanks, Adrian - - - - - - It might be nice if the Abstract gave a very simple explanation of "automatic bandwidth adjustment". You have text in the Introduction you could use. --- There are three bullets at the end of Section 1, but I lack the context to understand whether this is a list of possible approaches, a list of steps, or something else. --- I note that this revision seems to have dropped the ability for a PCC to report samples to the PCE and have the PCE do all of the work of determining whether auth-bandwidth adjustments are needed/desirable before performing the various path computations. There is a clear benefit in pushing the responsibility for deciding when adjustments are needed to the PCC. This distributes the load of monitoring the LSPs down to the PCCs and frees up the PCE as well as reducing the load on PCEP communications. However, ... Exactly when to adjust an LSP (and the scaling consequences discussed in 4.3) could be better left to a PCE. That is, a PCE could be flexible in its interpretation of thresholds enabling it to trigger adjustment early if it believes there is a good reason (for example, doing a set of parallel recomputations) or late (for example, when it knows that an adjustment would be disruptive to the network and can see the changes that lead to an adjustment request). When this is delegated to the PCC, the PCC cannot see the impact on other LSPs, and the PCE cannot tell whether the request for adjust the LSP is critical or moderate. Clearly there are options and trade-offs, and different pain points. Was there a logic to this edit? (BTW - Having a way for the PCC to report measurements to the PCE does not necessarily imply using a PCRpt for that purpose.) Note that in 4.2 you have The PCEP peer which is in-charge of calculating the bandwidth to be adjusted, will adjust the bandwidth of the LSP to the highest sampled traffic rate (MaxAvgBw) amongst the set of bandwidth samples collected over the adjustment-interval. I think that *in*your*current*revision* "The PCEP peer" means "the PCC" and that "the PCC" is congruent to the "LSP head end". Similarly, when you took text out in this revision, I think you missed updating 4.3 where you have... If a PCE gets overwhelmed, it can notify the PCC to temporarily suspend its auto-bandwidth reporting (see Section 5.6). ...yet the PCC does not (now) do auto-bandwidth reporting. --- I think the table in Section 3 slightly misses the point. The statement "No new extensions are needed" is currently applied to "PCC Initiated", but I think there may be confusion in the delegated case. That is, once delegated, a PCC *could* send a request for adjustment, but neither the PCC nor the PCE may really be expecting that. They may expect something more similar to the PCE-initiated case. Thus, at the time of delegation, the PCE needs to be able to say "yes, delegated, but I want you to monitor the LSP with these parameters." Maybe, also, at the time of delegation the PCC should be letting the PCE know what monitoring it is planning on doing. --- 4.1 has... Auto-Bandwidth feature allows an LSP to automatically and dynamically adjust its reserved bandwidth over time, i.e. without network operator intervention. Well, of course, the LSP does no such thing. Probably the head-end LSR does that. --- Did you consider allowing a different Adjustment-Interval for adjustment up and adjustment down (with them defaulting to the same value)? --- 4.2 has All thresholds in this document could be represented in both absolute value and percentage, and could be used together. I looked but couldn't find. If absolute and percentage are both supplied and imply different thresholds, which one is used? Could be as simple as "the first threshold hit", but this could lead to some flaps that are not obvious to someone staring at either the up/down percentage thresholds or at the up/down absolute values. --- 5.2 has For PCE-Initiated LSP ([I-D.ietf-pce-pce-initiated-lsp]), this TLV is included in the LSPA Object with PCInitiate message. For delegated LSPs, this TLV is carried in PCRpt message in LSPA Object. I *think* that a PCUpd can also carry these to allow a PCE to direct the PCC to use different parameters with the LSP. --- 5.2 The TLV is encoded in all PCEP messages for the LSP till the auto bandwidth adjustment feature is enabled, the absence of the TLV indicate the PCEP speaker wish to disable the feature. Does this mean The TLV is encoded in all PCEP messages for the LSP while the auto bandwidth adjustment feature is enabled, the absence of the TLV indicate the PCEP speaker wish to disable the feature. ?? --- 5.2 Length: Variable How true! But what does it encode? --- Do you need section 5.7 for PCUpd? --- You have... This document defines AUTO-BANDWIDTH-CAPABILITY TLV, AUTO-BANDWIDTH-ATTRIBUTE TLV which do not add any new security concerns beyond those discussed in [RFC5440] and [I-D.ietf-pce-stateful-pce]. Some deployments may find the reporting of the auto-bandwidth information as extra sensitive and thus SHOULD employ suitable PCEP security mechanisms like TCP-AO or [I-D.ietf-pce-pceps]. Are you sure there are no additional security concerns as stated in your first paragraph. Doesn't your second paragraph say that there *are* additional concerns: in particular that things be deduced from the fact of, the timing of, and the amount of adjustments? So even if the messages are protected from spoofing or modification, that wouldn't be enough. --- 7.2. Information and Data Models [RFC7420] describes the PCEP MIB, there are no new MIB Objects defined in this document. What you say is true. But do you think there is a need for an augmentation for the new features? What about YANG? --- 7.6. Impact On Network Operations Mechanisms defined in this document do not have any impact on network operations in addition to those already listed in [RFC5440]. Really? Haven't you described a mechanism specifically designed to change the way that the network is operated? Haven't you also described problems (and mitigations) that could cause PCC and PCE to be swamped? --- 8.2 "IETF Consensus" is now called "IETF Review". You also need a reference to RFC 5226. --- 8.3. AUTO-BANDWIDTH-ATTRIBUTE Sub-TLV You need to define the allocation policy for this new registry. --- The absence of TBD2 and TBD3 is not critical, but cause IANA and the RFC editor to ask you a question. From: Pce [mailto:pce-bounces@ietf.org] On Behalf Of Jonathan Hardwick Sent: 05 January 2017 15:24 To: pce@ietf.org Cc: draft-dhody-pce-stateful-pce-auto-bandwidth@ietf.org; pce-chairs@ietf.org Subject: [Pce] Poll for adoption: draft-dhody-pce-stateful-pce-auto-bandwidth-09 All, This is start of a two week poll on making draft-dhody-pce-stateful-pce-auto-bandwidth-09 a PCE working group document. https://datatracker.ietf.org/doc/draft-dhody-pce-stateful-pce-auto-bandwidth/ Please review the draft and send an email to the list indicating "yes/support" or "no/do not support". If indicating no, please state your reasons. If yes, please also feel free to provide comments you'd like to see addressed once the document is a WG document. The poll ends on Thursday January 19. Thanks, Jon, JP and Julien
- [Pce] Poll for adoption: draft-dhody-pce-stateful… Jonathan Hardwick
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Dhruv Dhody
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Udayasree palle
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Rakesh Gandhi
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Ravi Singh
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Sureshbr
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Shah, Himanshu
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Phil Bedard
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Leeyoung
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Jeff Tantsura
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Daniele Ceccarelli
- [Pce] 答复: Poll for adoption: draft-dhody-pce-stat… Zhenghaomian
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Adrian Farrel
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Jonathan Hardwick
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Dhruv Dhody
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Adrian Farrel
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Dhruv Dhody
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Dhruv Dhody
- Re: [Pce] Poll for adoption: draft-dhody-pce-stat… Adrian Farrel