Re: [Idr] TCP & BGP: Some don't send terminate BGP when holdtimer expired, because TCP recv window is 0

Randy Bush <randy@psg.com> Sat, 12 December 2020 18:55 UTC

Return-Path: <randy@psg.com>
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 B27643A0DEC for <idr@ietfa.amsl.com>; Sat, 12 Dec 2020 10:55:06 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.899
X-Spam-Level:
X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] 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 OEMi8PwWNTM9 for <idr@ietfa.amsl.com>; Sat, 12 Dec 2020 10:55:04 -0800 (PST)
Received: from ran.psg.com (ran.psg.com [IPv6:2001:418:8006::18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id AC9743A0DBA for <idr@ietf.org>; Sat, 12 Dec 2020 10:55:04 -0800 (PST)
Received: from localhost ([127.0.0.1] helo=ryuu.rg.net) by ran.psg.com with esmtp (Exim 4.90_1) (envelope-from <randy@psg.com>) id 1koA2o-0001VJ-JN; Sat, 12 Dec 2020 18:55:02 +0000
Date: Sat, 12 Dec 2020 10:55:02 -0800
Message-ID: <m2mtyietx5.wl-randy@psg.com>
From: Randy Bush <randy@psg.com>
To: Jared Mauch <jared@puck.nether.net>
Cc: Interminable Discussion Room <idr@ietf.org>
In-Reply-To: <746E64E4-F23F-455E-8AB4-4D306032E793@puck.nether.net>
References: <1B4E7C9D-BBFE-4865-87F9-133ACE55D122@cisco.com> <746E64E4-F23F-455E-8AB4-4D306032E793@puck.nether.net>
User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/26.3 Mule/6.0 (HANACHIRUSATO)
MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue")
Content-Type: text/plain; charset=ISO-2022-JP
Archived-At: <https://mailarchive.ietf.org/arch/msg/idr/XfUpYS0BTNM8DL_X8yjYpMJsLOo>
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: Sat, 12 Dec 2020 18:55:07 -0000

> One of the issues I've seen here is the tcp stacks in routers be very
> ... unique.

way back when, we looked at the tcp behavior of bgp on a few routers.
we gave up in disgust and did not publish (beyond a talk at nag, i
think).

maybe, over the years, newer or revised implementations are running on
linux, bsd, or other more widely reviewed and tested stacks.  this would
be a good thing.

but even behind a decent stack, the receiver might not be able to keep
up (for other disgusting reasons, historical cite albeit ospf [0]), so
the window narrows.  so i see this discussion as useful.

randy

[0] - Aman Shaikh and Albert Greenberg, “Experience in Black-box OSPF
      Measurement,” in Proc. ACM SIGCOMM Internet Mea- surement Workshop
      (IMW), November
      2001. http://conferences.sigcomm.org/imc/2001/imw2001-papers/82.pdf