Re: [Idr] TCP & BGP: Some don't send terminate BGP when holdtimer expired, because TCP recv window is 0
Jeffrey Haas <jhaas@pfrc.org> Wed, 16 December 2020 21:44 UTC
Return-Path: <jhaas@slice.pfrc.org>
X-Original-To: idr@ietfa.amsl.com
Delivered-To: idr@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 8013E3A1122 for <idr@ietfa.amsl.com>; Wed, 16 Dec 2020 13:44:01 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.901
X-Spam-Level:
X-Spam-Status: No, score=-1.901 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_PASS=-0.001] autolearn=unavailable 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 1xVMZ4MGnOpP for <idr@ietfa.amsl.com>; Wed, 16 Dec 2020 13:43:59 -0800 (PST)
Received: from slice.pfrc.org (slice.pfrc.org [67.207.130.108]) by ietfa.amsl.com (Postfix) with ESMTP id D91EA3A110D for <idr@ietf.org>; Wed, 16 Dec 2020 13:43:59 -0800 (PST)
Received: by slice.pfrc.org (Postfix, from userid 1001) id B39511E356; Wed, 16 Dec 2020 17:01:22 -0500 (EST)
Date: Wed, 16 Dec 2020 17:01:22 -0500
From: Jeffrey Haas <jhaas@pfrc.org>
To: Brian Dickson <brian.peter.dickson@gmail.com>
Cc: "Jakob Heitz (jheitz)" <jheitz=40cisco.com@dmarc.ietf.org>, "idr@ietf.org" <idr@ietf.org>
Message-ID: <20201216220122.GE24940@pfrc.org>
References: <9D6268BD-C555-4B9A-A883-9B55EEB5D5DA@juniper.net> <91D9B9F7-0DBE-45E6-84D5-2E3D9F8C44A1@tix.at> <X9kweQ5EtTL7tOAM@bench.sobornost.net> <CAOj+MMFySPXpE8QxcO+7szKzQ78faQASYKnBUYg_h_aLd=P4Lg@mail.gmail.com> <BYAPR11MB3207412804697588E4AA3F03C0C60@BYAPR11MB3207.namprd11.prod.outlook.com> <20201216093614.GI68083@diehard.n-r-g.com> <4E9BEA12-998A-4AD1-B342-4F26AA6EBA69@cisco.com> <20201216174319.GM68083@diehard.n-r-g.com> <BYAPR11MB320759EE6ABC8AB863BC1838C0C50@BYAPR11MB3207.namprd11.prod.outlook.com> <CAH1iCipjgS4-NPTjNhc7Cj73bitWgTcw=ufax7iOCCnT+xGiZQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <CAH1iCipjgS4-NPTjNhc7Cj73bitWgTcw=ufax7iOCCnT+xGiZQ@mail.gmail.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Archived-At: <https://mailarchive.ietf.org/arch/msg/idr/ru2hNpNQHdIRVEY99W4onMsnv3c>
Subject: Re: [Idr] TCP & BGP: Some don't send terminate BGP when holdtimer expired, because TCP recv window is 0
X-BeenThere: idr@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Inter-Domain Routing <idr.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/idr>, <mailto:idr-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/idr/>
List-Post: <mailto:idr@ietf.org>
List-Help: <mailto:idr-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/idr>, <mailto:idr-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 16 Dec 2020 21:44:01 -0000
Brian, On Wed, Dec 16, 2020 at 11:17:37AM -0800, Brian Dickson wrote: > Which is to say, there is EVERY reason to delete forwarding state. > If a peer's router is so messed up that it is not accepting any TCP > packets, the only safe assumption is that the problem is AS-wide for that > peer. While your later text does cover concerns about AS-wide events, I'd like to suggest that your assumption doesn't necessarily hold. A situation where we enter a half-duplex state and simply can't get a response to packets we're pushing might simply impact a single peering session. The demonstration machinery Job mentions elsewhere in-thread is an example of this. Active attacks against TCP windowing mechanisms are another. > While this is my opinion on the best way to handle it, the underlying facts > aren't arguable. > An AS-wide situation (stuck receivers with no TCP progress) would never > result in the AS sending withdrawals. For the incident in question, it's not possible for a single BGP implementation to decide that something AS-wide is happening. And even so, auto-mitigation of this triggered by a single session on a single device would be unwise. > It has occured and can occur, ergo it needs to be handled outside of the > state machine proper. For the demonstrated case, a coordinated response was needed. To some extent, the argument is for tooling to permit easy shutdown of sessions. Operators have plenty of provisioning machinery. Writing up the use case and motivations for encouraging such a thing seems like something appropriate to an operational forum. -- Jeff
- [Idr] TCP & BGP: Some don't send terminate BGP wh… Job Snijders
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Tony Li
- Re: [Idr] TCP & BGP: Some don't send terminate BG… John Scudder
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeff Tantsura
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Job Snijders
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Tony Li
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Keyur Patel
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeff Tantsura
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Keyur Patel
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Christoph Loibl
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Christoph Loibl
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jared Mauch
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jared Mauch
- Re: [Idr] TCP & BGP: Some don't send terminate BG… William McCall
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Job Snijders
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jared Mauch
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Randy Bush
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jared Mauch
- Re: [Idr] TCP & BGP: Some don't send terminate BG… John Scudder
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Christoph Loibl
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… John Scudder
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Job Snijders
- Re: [Idr] TCP & BGP: Some don't send terminate BG… John Scudder
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… john heasley
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Tony Li
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Keyur Patel
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Keyur Patel
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Brian Dickson
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Claudio Jeker
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Claudio Jeker
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Job Snijders
- Re: [Idr] TCP & BGP: Some don't send terminate BG… John Heasley
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Claudio Jeker
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Brian Dickson
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Job Snijders
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Job Snijders
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Job Snijders
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Brian Dickson
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeffrey Haas
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeffrey Haas
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeffrey Haas
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeffrey Haas
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Brian Dickson
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Gert Doering
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Claudio Jeker
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeffrey Haas
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeffrey Haas
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Brian Dickson
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeffrey Haas
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Brian Dickson
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeffrey Haas
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jakob Heitz (jheitz)
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Gyan Mishra
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeffrey Haas
- Re: [Idr] TCP & BGP: Some don't send terminate BG… John Scudder
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Gyan Mishra
- Re: [Idr] TCP & BGP: Some don't send terminate BG… William McCall
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Gyan Mishra
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Gyan Mishra
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Gyan Mishra
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Jeffrey Haas
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Gyan Mishra
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Robert Raszuk
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Gyan Mishra
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Gyan Mishra
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Job Snijders
- Re: [Idr] TCP & BGP: Some don't send terminate BG… Enke Chen