From owner-freebsd-net Thu Oct 24 6:38:21 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5B9DF37B401 for ; Thu, 24 Oct 2002 06:38:20 -0700 (PDT) Received: from web.cs.ndsu.nodak.edu (web.cs.ndsu.NoDak.edu [134.129.125.7]) by mx1.FreeBSD.org (Postfix) with ESMTP id A6E6143E6A for ; Thu, 24 Oct 2002 06:38:19 -0700 (PDT) (envelope-from tinguely@web.cs.ndsu.nodak.edu) Received: (from tinguely@localhost) by web.cs.ndsu.nodak.edu (8.11.4/8.11.4) id g9ODcAx33485; Thu, 24 Oct 2002 08:38:10 -0500 (CDT) (envelope-from tinguely) Date: Thu, 24 Oct 2002 08:38:10 -0500 (CDT) From: mark tinguely Message-Id: <200210241338.g9ODcAx33485@web.cs.ndsu.nodak.edu> To: bbaumann@isilon.com, freebsd-net@FreeBSD.ORG Subject: Re: tcp_input's header prediction and a collapsing send window In-Reply-To: Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org > After taking a close look at tcp_input, I think I see a senario where this > could happen. Say header prediction handles ~2 GB of data without > problems, then a retransmission happens. snd_wnd starts collapsing as it > should. The header prediction code is correctly skipped as the snd_wnd no > long matches the advertised window. We recover from the retransmission, > *BUT* the code that reopens window is skipped because of rolled over > sequence numbers. probably in the same sequence, we took a possibly un-necessay timeout because quick recovery was suppressed because of a wrapped snd_recover. These variables should be kept more up to date. --Mark Tinguely To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message