Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last call review of draft-ietf-v6ops-ipv6-ehs-packet-drops-05
Fernando Gont <fgont@si6networks.com> Thu, 08 April 2021 00:03 UTC
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To: Tom Herbert <tom@herbertland.com>, "Rob Wilton (rwilton)" <rwilton@cisco.com>
Cc: Gorry Fairhurst <gorry@erg.abdn.ac.uk>, IPv6 Operations <v6ops@ietf.org>, "draft-ietf-v6ops-ipv6-ehs-packet-drops.all@ietf.org" <draft-ietf-v6ops-ipv6-ehs-packet-drops.all@ietf.org>, "last-call@ietf.org" <last-call@ietf.org>, "tsv-art@ietf.org" <tsv-art@ietf.org>
References: <161366727749.10107.14514005068158901089@ietfa.amsl.com> <e41f3484-f816-e185-2d99-94323c8da732@si6networks.com> <CALx6S34qSxGijVcs229bAL5gMhMvMNYUXm3yEmrg6wxUiUAiaA@mail.gmail.com> <bf83d228-25bc-21bb-f984-d58ead6bf492@si6networks.com> <CALx6S35Kh-QAXJDAucuw5Wty37MBiwS=pqQknMZ+15b7D5Sn8A@mail.gmail.com> <34e78618-cb28-71a1-a9d3-7aec38032659@si6networks.com> <CAO42Z2zqD9_d2Fbr25Y2CV1GdzYKd167yf5DHeHna7V66pF65A@mail.gmail.com> <0bd316ac-1789-f4c6-d280-943ad6e60309@si6networks.com> <CALx6S34dMEEJ+OPUu_=FW1Y5AQuvAaHzBPEe448S7rfbMmHN_w@mail.gmail.com> <CEFDF511-9255-4913-840D-50CCBC2B7B17@gmail.com> <CALx6S36_w+zxyUt0DzQ9NKBs+SAPZDNhs_sqLBwi+qneOPSS5A@mail.gmail.com> <ef2bd4f5-3b1e-b88c-ec8f-dd9a2f9a60ba@si6networks.com> <CALx6S349X7fQR=9Dj+n5X7ovXsSjLYibv-C-+bL0nkWsYP5NGA@mail.gmail.com> <MN2PR11MB43668EDA6209CA6AF3BCC5EEB5759@MN2PR11MB4366.namprd11.prod.outlook.com> <CALx6S3447SJwdRPoG_BaXS=ihBe1xA84vxcCev1y2K4xqMYZaQ@mail.gmail.com>
From: Fernando Gont <fgont@si6networks.com>
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Date: Wed, 07 Apr 2021 21:03:26 -0300
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Subject: Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last call review of draft-ietf-v6ops-ipv6-ehs-packet-drops-05
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Hi, Tom, On 7/4/21 12:20, Tom Herbert wrote: [....] > Given that hosts are the ones creating extensions headers and other > packet formats, hosts have a vested interest in how routers are > dealing with their packets. Even before this document was created, we > have long known that extensions headers might be dropped and have been > working on mitigations to reduce the number of drops which are already > addressing some of the reasons that packets with EH. For instance, > consider draft-hinden-6man-hbh-processing-00; this is a proposal to > limit the number of HBH options to exactly one. The idea is that > routers will make it feasible for routers packets that have HBH > options, with the trade off of specifically limiting the extensibility > of the protocol. The problem is there is no data that indicates this > proposal would have the desired effect; we don't if routers would > start accepting packets that are limited to one HBH option. What does that proposal have to do with this document? > So my fundamental concern with this draft is that it is an entirely > qualitative description of a well known problem, however a qualitative No. It is not a well known problem. If you look at draft-hinden-6man-hbh-processing, itś clear that their assumption is that limiting the number of EHs or options solves the problem. Whereas our document essentially notes that to a large extent the problem has to do with the overall EH-chain length -- it doesn't matter if the EH-chain: it doesn matter whether you have one long EH, multiple small ones, one large EH with one large option, one large EH with many small options, or any combination of them. The fact that youŕe raising this issue and that thereś a belief that there'ś a clear and easy way to make EHs work probes that itś certainly not a well known problem. I can also say that I have consulted for different operators, and they were not even aware about this issue. > analysis is insufficient input for moving extension headers forward. Please read the Abstract: This document summarizes the operational implications of IPv6 extension headers specified in the IPv6 protocol specification (RFC8200), and attempts to analyze reasons why packets with IPv6 extension headers are often dropped in the public Internet. and the disclaimer: 2. Disclaimer This document analyzes the operational challenges represented by packets that employ IPv6 Extension Headers, and documents some of the operational reasons why these packets are often dropped in the public Internet. This document is not a recommendation to drop such packets, but rather an analysis of why they are dropped. If you want to embark in the project of "moving Ehs forward", getting whatever data you need for that, etc., thatś totally fine. > In the draft, there are several reasons suggested as to why routers > might drop packets, however there is no indication of the relative > occurrence frequency of these. Also, there are parameterizations > mentioned such as in the state that routers might drop if the chain is > "too long", there is no analysis on exactly what "too long" commonly We discussed this one to death: Thatś impossible to tell. Itś implementation dependent, and the information may not even be public. > and deployment thereby providing actionable data. Note this is not the > same as making recommendations, I am just asking for the operational > data as part of the analysis from which we could derive guidance or > new protocol requirements. You are asking for a different document. If you want that data, I encourage you to start the experiment, and submit an I-D with the results. Some of us did that homework for the data that we considered useful, and provided it to the community in RFC7872. If that data is not enough, I certainly encourage you to work on that. But thatś a project thatś totally unrelated to this document. Thanks, -- Fernando Gont e-mail: fgont@si6networks.com PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
- [Tsv-art] Tsvart last call review of draft-ietf-v… Gorry Fairhurst via Datatracker
- Re: [Tsv-art] Tsvart last call review of draft-ie… Fernando Gont
- Re: [Tsv-art] [Last-Call] Tsvart last call review… Brian E Carpenter
- Re: [Tsv-art] [Last-Call] Tsvart last call review… Fernando Gont
- Re: [Tsv-art] Tsvart last call review of draft-ie… Gorry Fairhurst
- Re: [Tsv-art] [Last-Call] Tsvart last call review… Brian E Carpenter
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [Last-Call] Tsvart last call review… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] Tsvart last call review of draft-ie… Fernando Gont
- Re: [Tsv-art] Tsvart last call review of draft-ie… Nick Hilliard
- Re: [Tsv-art] Tsvart last call review of draft-ie… Gorry Fairhurst
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [Last-Call] [v6ops] Tsvart last cal… Nick Hilliard
- Re: [Tsv-art] [Last-Call] Tsvart last call review… Nick Hilliard
- Re: [Tsv-art] [Last-Call] [v6ops] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [Last-Call] [v6ops] Tsvart last cal… Nick Hilliard
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Nick Hilliard
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Nick Hilliard
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fred Baker
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Nick Hilliard
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Mark Smith
- Re: [Tsv-art] [Last-Call] [v6ops] Tsvart last cal… Joseph Touch
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [Last-Call] [v6ops] Tsvart last cal… Joseph Touch
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Mark Smith
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fred Baker
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Rob Wilton (rwilton)
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Nick Hilliard
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Brian E Carpenter
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Fernando Gont
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Rob Wilton (rwilton)
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [Last-Call] [v6ops] Tsvart last cal… Timothy J. Salo
- Re: [Tsv-art] [Last-Call] [v6ops] Tsvart last cal… Tom Herbert
- Re: [Tsv-art] [v6ops] [Last-Call] Tsvart last cal… Brian E Carpenter