From owner-freebsd-net@FreeBSD.ORG Sat Jul 14 18:41:43 2007 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 6B41416A404 for ; Sat, 14 Jul 2007 18:41:43 +0000 (UTC) (envelope-from brian@Awfulhak.org) Received: from storm.uk.FreeBSD.org (storm.uk.FreeBSD.org [194.242.157.42]) by mx1.freebsd.org (Postfix) with ESMTP id E615713C442 for ; Sat, 14 Jul 2007 18:41:42 +0000 (UTC) (envelope-from brian@Awfulhak.org) Received: from store.lan.Awfulhak.org (store.lan.Awfulhak.org [172.16.0.35]) by storm.uk.FreeBSD.org (8.14.1/8.14.1) with ESMTP id l6EIfeNY019018; Sat, 14 Jul 2007 19:41:40 +0100 (BST) (envelope-from brian@Awfulhak.org) Received: from store.lan.Awfulhak.org (localhost.localdomain [127.0.0.1]) by localhost (Email Security Appliance) with SMTP id E3D1B1957C7F; Sat, 14 Jul 2007 18:42:14 +0000 (GMT) Received: from gw.Awfulhak.org (gw.lan.Awfulhak.org [172.16.0.1]) by store.lan.Awfulhak.org (Email Security Appliance) with ESMTP id 8C2BE1957C7D; Sat, 14 Jul 2007 18:42:10 +0000 (GMT) Received: from dev.lan.Awfulhak.org (brian@dev.lan.Awfulhak.org [172.16.0.5]) by gw.Awfulhak.org (8.14.1/8.14.1) with ESMTP id l6EIfYXm015523; Sat, 14 Jul 2007 11:41:34 -0700 (PDT) (envelope-from brian@Awfulhak.org) Date: Sat, 14 Jul 2007 11:41:32 -0700 From: Brian Somers To: Brett Glass Message-ID: <20070714114132.6b395616@dev.lan.Awfulhak.org> In-Reply-To: <200707120114.TAA28481@lariat.net> References: <200707110014.SAA02181@lariat.net> <200707120114.TAA28481@lariat.net> X-Mailer: Claws Mail 2.10.0 (GTK+ 2.10.13; i386-portbld-freebsd7.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org, Mike Tancsa Subject: Re: Bug in userland PPP LQR? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 14 Jul 2007 18:41:43 -0000 On Wed, 11 Jul 2007 19:14:03 -0600 Brett Glass wrote: > At 06:23 PM 7/11/2007, Mike Tancsa wrote: > > >Did you try and use just LCP echo mode instead ? I have come across a > >number of devices (especially GPRS/EVDO cards) that seem to say yes to > >supporting LQR, but do not. Try instead lcp echo > > I will try it. (To be more specific, I am going to try > > disable lqr > allow lqr accept lqr > enable echo > echoperiod 12 set echoperiod 12 > so that the peer can get LQR if it requests it.) But since this would > just be working around the bug I think might be there, it would also > be a good idea to look at how the LQR counter is managed. From what > I can see, the problem is that the counter either is cumulative or > counts irrevocably up to 5 after one LQR packet is missed. The > reason why I'd like to see more eyes than my own on this is that > it's difficult to see how and where the LQR routines are invoked > and how they react to a pattern of missed and un-missed packets. I'd also add "set log +lqm" to your configuration. Disabling lqr should just remove the problem as there will be no calls to SendLqrReport(). Try adding the lqm logging with lqr enabled too. It'd be interesting to see what's actually being sent out. I expect unacknowledged LQR packets to be resent 5 times (exactly the same packet), and the 6th timeout to cause a line drop. The spec says that the peer may ignore an LQR request if it's under load, but that it must respond to a duplicate LQR request. My suspicion is that some implementations just ignore LQR altogether under load. These implementations should disable LQR if they can't implement it properly. Of course the *other* option is to implement an LQM strategy. I've never come up with anything that might really be useful though - except for suggesting that LQR is disabled. -- Brian Somers Don't _EVER_ lose your sense of humour !