From owner-freebsd-questions@FreeBSD.ORG Thu Jul 7 14:23:15 2005 Return-Path: X-Original-To: questions@freebsd.org Delivered-To: freebsd-questions@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A8C7316A41C for ; Thu, 7 Jul 2005 14:23:15 +0000 (GMT) (envelope-from mark@gaiahost.coop) Received: from biodiesel.gaiahost.coop (biodiesel.gaiahost.coop [64.95.78.120]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5BDFE43D45 for ; Thu, 7 Jul 2005 14:23:15 +0000 (GMT) (envelope-from mark@gaiahost.coop) Received: from rabbit.hubcapconsulting.com (host-216-153-147-194.spr.choiceone.net [::ffff:216.153.147.194]) (AUTH: LOGIN mark@hubcapconsulting.com) by biodiesel.gaiahost.coop with esmtp; Thu, 07 Jul 2005 10:23:12 -0400 id 008A400E.42CD3AD2.00007355 Received: by rabbit.hubcapconsulting.com (sSMTP sendmail emulation); Thu, 7 Jul 2005 10:23:11 -0400 Date: Thu, 7 Jul 2005 10:23:11 -0400 From: Mark Bucciarelli To: questions@freebsd.org Message-ID: <20050707142311.GL2792@rabbit> Mail-Followup-To: questions@freebsd.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline User-Agent: Mutt/1.4.2.1i Cc: Subject: Network Debugging X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 07 Jul 2005 14:23:15 -0000 I'm trying to improve the performance of our rural homebrew wireless broadband and am hoping some of the folks here can give me a pointer or two as to what network monitoring tools I should use. Background: - my internet access is five wireless and five wired hops downstream from a 1/2 T1 (ten Buffalo AirStation G54 routers in all). - my connection has a lot of jitter--ping's usually vary from 10ms to 150ms within a two second window - FWIU, jitter is related to congestion - I have setup a FreeBSD box to monitor [1] each router along the path using smokeping. The smokeping charts are showing me some interesting stuff. Here is some data from the past three hours (I am using the smokeping default of 20 pings sent every five minutes): |--------- Building 1 --------------| |--- Bldg 0 --... +-----------+ +------------+ +-----------+ | .203 | | .202 | | .201 | | Router In |<- wire ->| Router Out |<- wireless ->| Router In | +-----------+ +------------+ +-----------+ avg RTT: 7.3ms 12.1ms 7.8ms % lost: 2.37% 14.25% 2.64% max RTT: 20ms 80ms 13ms My FreeBSD box is a four more wireless hops to the left of .203. A slew of questions ... What is going on here? I am confused by the max RTT readings and packet loss stats for .202 and .201. How can a router further away from me have better performance? Over the past 13 hours, the averages are consistent with the three-hour averages, while the Max RTT discrepancies are even higher: .203 / .202 / .201 = 20ms / 145ms / 13ms. Is .202 congested? Is the .202 router "bad"? How can I debug this further? SNMP? If SNMP, what values should I track/inspect? - # of packets with errors? - # of queued packets? - ?? Thanks for any pointers, m [1] Pentium II 350MHz with 4 Gb drive, underclocked to 100MHz so I can turn off the power supply fan and make it real quiet. :)