Re: [PWE3] GAL above and below the PW label
Curtis Villamizar <curtis@occnc.com> Thu, 31 March 2011 12:47 UTC
Return-Path: <curtis@occnc.com>
X-Original-To: pwe3@core3.amsl.com
Delivered-To: pwe3@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 965EA3A6B12 for <pwe3@core3.amsl.com>; Thu, 31 Mar 2011 05:47:55 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.216
X-Spam-Level:
X-Spam-Status: No, score=-2.216 tagged_above=-999 required=5 tests=[AWL=-0.217, BAYES_00=-2.599, J_CHICKENPOX_13=0.6]
Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id e3XEIR6FQJkT for <pwe3@core3.amsl.com>; Thu, 31 Mar 2011 05:47:54 -0700 (PDT)
Received: from harbor.orleans.occnc.com (harbor.orleans.occnc.com [173.9.106.135]) by core3.amsl.com (Postfix) with ESMTP id 2033C28C0EB for <pwe3@ietf.org>; Thu, 31 Mar 2011 05:47:54 -0700 (PDT)
Received: from harbor.orleans.occnc.com (harbor.orleans.occnc.com [173.9.106.135]) by harbor.orleans.occnc.com (8.13.6/8.13.6) with ESMTP id p2VCnU9Y085450; Thu, 31 Mar 2011 08:49:30 -0400 (EDT) (envelope-from curtis@harbor.orleans.occnc.com)
Message-Id: <201103311249.p2VCnU9Y085450@harbor.orleans.occnc.com>
To: Sriganesh Kini <sriganesh.kini@ericsson.com>
From: Curtis Villamizar <curtis@occnc.com>
In-reply-to: Your message of "Thu, 31 Mar 2011 05:40:07 PDT." <AANLkTi=fuSg1iBy+jz0SvsfNpGrd-=32p+KMV7Q=hOSv@mail.gmail.com>
Date: Thu, 31 Mar 2011 08:49:30 -0400
Sender: curtis@occnc.com
Cc: "pwe3@ietf.org" <pwe3@ietf.org>
Subject: Re: [PWE3] GAL above and below the PW label
X-BeenThere: pwe3@ietf.org
X-Mailman-Version: 2.1.9
Precedence: list
Reply-To: curtis@occnc.com
List-Id: Pseudo Wires Edge to Edge <pwe3.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/listinfo/pwe3>, <mailto:pwe3-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/pwe3>
List-Post: <mailto:pwe3@ietf.org>
List-Help: <mailto:pwe3-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/pwe3>, <mailto:pwe3-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 31 Mar 2011 12:47:55 -0000
In message <AANLkTi=fuSg1iBy+jz0SvsfNpGrd-=32p+KMV7Q=hOSv@mail.gmail.com> Sriganesh Kini writes: > > See inline > > On Thu, Mar 31, 2011 at 4:40 AM, Curtis Villamizar <curtis@occnc.com> wrote: > > > > Sriganesh, Sasha, Loa, Dave, > > > > Would you please not top post. See inline. > > > > Curtis > > > > In message <AANLkTimGJTVa42CFsj-PRcLiPLGTBhZ-t3sNRcTadHHe@mail.gmail.com> > > Sriganesh Kini writes: > >> > >> Sasha, that issue with VCCV Type-3 (without CW) is not addressed by > >> the draft. Practically, is that a major issue ? Especially setting TTL > >> > 1 for SS PW is possible I guess but would be some kind of serious > >> operational oversight. Besides such a packet would fail some check > >> along the path. > > > > End to end OAM should set TTL>1 and not use VCCV Type-3. The T-PE may > > not have reliable information to set TTL, so in MS-PW it might be > > worth discouraging VCCV Type-3 except for use as a traceroute > > capability or to address S-PEs by node distance along the path. > > If there is indeed a concern of TTL exceeding number of segments (with > Type-3 and no CW), the same concern would apply when tracing. So > tracing would be impossible. traceroute stops when it hits the egress. > >> Also, what I heard at the mic regarding impl results is that it > >> doesn't make sense to deprecate what is already deployed. > > > > Yes. But VCCV Type-3 with MS-PW is not already deployed. > > I am not aware of the survey addressing this. AFAIK Type-1 is being used, but I could be wrong. Maybe someone who has implemented and knows of a deployment or someone who has deployed can reply so we don't need another survey. > >> Note that CC Type 1 prevents ECMP (when FAT-PW is not available). > >> Using GAL below PW also requires ECMP based on label hashing to ignore > >> reserved labels. > > > > You don't want ECMP to hash on PW payload. With CW and without > > fat-pw, you don't get ECMP on a PW but you do get ECMP on an LSP > > containing many PW. > > When the PW payload is IP, the hashing it for ECMP is useful (If the > payload is not IP then use CW). FAT-PW may not be present in all > deployments. I really don't know that any PW are carrying IP. That was not in the survey. L3VPN would be carrying IP. > >> 2011/3/31 Alexander Vainshtein <Alexander.Vainshtein@ecitele.com>: > >> > Sriganesh, Curtis and all, > >> > IMHO and FWIW I think that the only problem with VCCV Type 3 is the > >> > risk of OAM packets leaking out of T-PE towards the AC (if you > >> > accidentally set the TTL value too high). To the best of my > >> > understanding the offset proposal does not solve that - or did I miss > >> > something? > >> > > >> > One way to solve it is to use VCCV Type 1 (clean where applicable). > >> > Another way would be by using GAL below the PW label (possible but > >> > messy). If the industry moves towards deprecating Ethernet PWs > >> > without CW, it becomes completely unnecessary. > >> > > >> > My 2c, > >> > Sasha > > > > This is the context suggesting a potential problem with VCCV Type 3. > > > >> >> -----Original Message----- > >> >> From: pwe3-bounces@ietf.org [mailto:pwe3-bounces@ietf.org] On Behalf Of > >> >> Sriganesh Kini > >> >> Sent: Thursday, March 31, 2011 10:09 AM > >> >> To: curtis@occnc.com > >> >> Cc: pwe3@ietf.org > >> >> Subject: Re: [PWE3] GAL above and below the PW label > >> >> > >> >> All, > >> >> > >> >> Just an FYI that a proposal for fate-sharing PW OAM and data given in > >> >> draft-kini-pwe3-inband-cc-offset > >> >> > >> >> Just to summarize the proposal. > >> >> 1. It does not require GAL in PW. TTL expiry is used to alert the S/T- > >> >> PE. > >> >> 2. It is mainly applicable when CW is not used in the PW. > >> >> 3. It uses a fixed offset (negotiated between PW endpoints) after the > >> >> label stack before starting the OAM msg. > >> >> 4. The bytes between the label-stack and the fixed offset is referred > >> >> to as a pseudoflow header and is filled with byte-values (by the PE) > >> >> that represent the flow for which OAM is desired. This helps PW OAM > >> >> and data to fate-share even when the intermediate node looks beyond > >> >> label stack to do multipath forwarding decisions. > >> >> > >> >> > >> >> On Thu, Mar 31, 2011 at 12:03 AM, Curtis Villamizar <curtis@occnc.com> > >> >> wrote: > >> >> > > >> >> > Loa, Dave, Sasha, > >> >> > > >> >> > I've snipped from various posts on the thread that Sasha started. > >> >> See > >> >> > inline. > >> >> > > >> >> > In message <4D92F5D3.6080609@pi.nu> > >> >> > Loa Andersson writes: > >> >> >> > >> >> >> All, > >> >> >> > >> >> >> missed a nuance in Sasha subject line. > >> >> >> > >> >> >> We have two issues > >> >> >> > >> >> >> - where the GAL is placed relative to the PW label, I believe it is > >> >> >> necessary to have the GAL below the PW label. > >> >> >> > >> >> >> - whether the the GAL label needs to be bottom of stack or not, it > >> >> >> figure that this is really a discussion if it is possible to have > >> >> >> a FAT label below the GAL or not. I'm not sure about my > >> >> preferences > >> >> >> but I think it is possible. > >> >> >> > >> >> >> /Loa > >> >> > > >> >> > I agree with Loa's summary. Not putting GAL at the bottom may > >> >> confuse > >> >> > some LSR, but putting it above the PW label is likely to be even more > >> >> > problematic. > >> >> > > >> >> > > >> >> > In message > >> >> <60C093A41B5E45409A19D42CF7786DFD51D5310B53@EUSAACMS0703.eamcs.ericsson > >> >> .se> > >> >> > David Allan I writes: > >> >> >> > >> >> >> It does become a new behavior, GAL with S=3D0. However the > >> >> combination of G= > >> >> >> AL being top label at the S-PE and TTL being encoded in the PW label > >> >> means = > >> >> >> that fate sharing is broken at every S-PE. Life only gets a little > >> >> more str= > >> >> >> ange if there is a FAT label as well... > >> >> >> > >> >> >> That being said, GAL as bottom label is broken in any ECMP > >> >> environment, whi= > >> >> >> ch is why GAL is a TP construct. > >> >> >> > >> >> >> my 2 cents > >> >> >> D > >> >> > > >> >> > Dave, > >> >> > > >> >> > If GAL is broken for ECMP, which it is, then all TP OAM is broken. > >> >> > If all it takes to fix it is simple then lets just fix it. > >> >> > > >> >> > This is what we'd have to do. > >> >> > > >> >> > 1) Relax the requirement that GAL be at the bottom > >> >> > > >> >> > 2) Have the ingress insert GAL in the stack immediately below the > >> >> > label for which the measurement is made, keeping the rest of the > >> >> > label stack in place. > >> >> > > >> >> > The only thing the midpoing LSR at a multipath (LAG, link bundle for > >> >> > MPLS) has to do is skip over the GAL when hashing, as if the GAL > >> >> > wasn't there. That will yield the same hash value and it will > >> >> > preserve fate-sharing across multipath. > >> >> > > >> >> > I prefer that we fix things rather than complain that they are > >> >> broken. > >> >> > > >> >> > Curtis > >> >> > _______________________________________________ > >> >> > pwe3 mailing list > >> >> > pwe3@ietf.org > >> >> > https://www.ietf.org/mailman/listinfo/pwe3 > >> >> > > >> >> > >> >> > >> >> > >> >> -- > >> >> - Sri > >> >> _______________________________________________ > >> >> pwe3 mailing list > >> >> pwe3@ietf.org > >> >> https://www.ietf.org/mailman/listinfo/pwe3 > >> > _______________________________________________ > >> > pwe3 mailing list > >> > pwe3@ietf.org > >> > https://www.ietf.org/mailman/listinfo/pwe3 > >> > > >> > >> > >> > >> -- > >> - Sri > >> > >> > > > > _______________________________________________ > > pwe3 mailing list > > pwe3@ietf.org > > https://www.ietf.org/mailman/listinfo/pwe3
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Daniel Cohn
- Re: [PWE3] GAL above and below the PW label Alexander Vainshtein
- [PWE3] GAL above and below the PW label Alexander Vainshtein
- Re: [PWE3] GAL above and below the PW label Loa Andersson
- Re: [PWE3] GAL above and below the PW label Sam Aldrin
- Re: [PWE3] GAL above and below the PW label David Allan I
- Re: [PWE3] GAL above and below the PW label Alexander Vainshtein
- Re: [PWE3] GAL above and below the PW label David Allan I
- Re: [PWE3] GAL above and below the PW label Loa Andersson
- Re: [PWE3] GAL above and below the PW label Alexander Vainshtein
- Re: [PWE3] GAL above and below the PW label Greg Mirsky
- Re: [PWE3] GAL above and below the PW label Alexander Vainshtein
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label David Allan I
- Re: [PWE3] GAL above and below the PW label Greg Mirsky
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Alexander Vainshtein
- Re: [PWE3] GAL above and below the PW label Sriganesh Kini
- Re: [PWE3] GAL above and below the PW label Alexander Vainshtein
- Re: [PWE3] GAL above and below the PW label Stewart Bryant
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Sriganesh Kini
- Re: [PWE3] GAL above and below the PW label Alexander Vainshtein
- Re: [PWE3] GAL above and below the PW label Alexander Vainshtein
- Re: [PWE3] GAL above and below the PW label Giles Heron
- Re: [PWE3] GAL above and below the PW label Sriganesh Kini
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Sriganesh Kini
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Sriganesh Kini
- Re: [PWE3] GAL above and below the PW label venkatesan mahalingam
- Re: [PWE3] GAL above and below the PW label Stewart Bryant
- Re: [PWE3] GAL above and below the PW label Benjamin Niven-Jenkins
- Re: [PWE3] GAL above and below the PW label neil.2.harrison
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label neil.2.harrison
- Re: [PWE3] GAL above and below the PW label neil.2.harrison
- Re: [PWE3] GAL above and below the PW label Benjamin Niven-Jenkins
- Re: [PWE3] GAL above and below the PW label neil.2.harrison
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Luca Martini
- Re: [PWE3] GAL above and below the PW label Luca Martini
- Re: [PWE3] GAL above and below the PW label Sam Aldrin
- Re: [PWE3] GAL above and below the PW label Luca Martini
- Re: [PWE3] GAL above and below the PW label David Allan I
- Re: [PWE3] GAL above and below the PW label Sam Aldrin
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label David Allan I
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Sam Aldrin
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Jia He
- Re: [PWE3] GAL above and below the PW label Curtis Villamizar
- Re: [PWE3] GAL above and below the PW label Lucy yong
- Re: [PWE3] GAL above and below the PW label Carlos Pignataro
- Re: [PWE3] GAL above and below the PW label Sriganesh Kini
- Re: [PWE3] GAL above and below the PW label Carlos Pignataro (cpignata)
- Re: [PWE3] GAL above and below the PW label Sriganesh Kini
- Re: [PWE3] GAL above and below the PW label Carlos Pignataro
- Re: [PWE3] GAL above and below the PW label Sriganesh Kini
- Re: [PWE3] GAL above and below the PW label Carlos Pignataro (cpignata)
- Re: [PWE3] GAL above and below the PW label Sriganesh Kini
- Re: [PWE3] GAL above and below the PW label Carlos Pignataro (cpignata)