From owner-freebsd-questions@FreeBSD.ORG Fri Feb 19 03:20:28 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4834B106568D for ; Fri, 19 Feb 2010 03:20:28 +0000 (UTC) (envelope-from Olivier.Nicole@cs.ait.ac.th) Received: from mail.cs.ait.ac.th (mail.cs.ait.ac.th [192.41.170.16]) by mx1.freebsd.org (Postfix) with ESMTP id E8DED8FC16 for ; Fri, 19 Feb 2010 03:20:27 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mail.cs.ait.ac.th (Postfix) with ESMTP id 104733A386D for ; Fri, 19 Feb 2010 10:20:26 +0700 (ICT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cs.ait.ac.th; h= references:subject:subject:in-reply-to:from:from:message-id:date :date:received:received:received; s=selector1; t=1266549625; x= 1268364025; bh=OnMg6M9Xpm+Qgwsdy04q6Q5hgn/ONfX5giSeXL4eZ8k=; b=f mQpNeSoaKXf+aG1JRNQZqURxssjmjwy6YyGDHCzDzhPv3m88Z9TQzzSqxDPvoAgS 9UTkKF1rvclulSaD+AU4kmF3gbQBTfHdIENZMr7gXQQe2FH6FLN95G5A2LM6H/3Z 86EL7i2kGMHwIrZAvRGlPDsWDPAfmfpp+/6Ld7wvJs= X-Virus-Scanned: amavisd-new at cs.ait.ac.th Received: from mail.cs.ait.ac.th ([127.0.0.1]) by localhost (mail.cs.ait.ac.th [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id 0+PCNj-Sftph for ; Fri, 19 Feb 2010 10:20:25 +0700 (ICT) Received: from banyan.cs.ait.ac.th (banyan.cs.ait.ac.th [192.41.170.5]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.cs.ait.ac.th (Postfix) with ESMTPS id 6151D3A382C for ; Fri, 19 Feb 2010 10:20:25 +0700 (ICT) Received: (from on@localhost) by banyan.cs.ait.ac.th (8.14.3/8.14.3/Submit) id o1J3KOOS045254; Fri, 19 Feb 2010 10:20:24 +0700 (ICT) (envelope-from on) Date: Fri, 19 Feb 2010 10:20:24 +0700 (ICT) Message-Id: <201002190320.o1J3KOOS045254@banyan.cs.ait.ac.th> From: Olivier Nicole To: freebsd-questions@freebsd.org In-reply-to: (message from Kurt Buff on Thu, 18 Feb 2010 18:56:46 -0800) References: <8CCEB7E2804F4187B322D59004AAA8A1@desktop2002> Subject: Re: is there a tool for estimating loss rates 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: Fri, 19 Feb 2010 03:20:28 -0000 Hi, > I have 2 leasedlines for internet. the one is in a country. other one is in > a another country. > I am looking for a tool for estimating loss packets between 2 lines. > is there a tool for it? > for instance , while searching, I found badabing tool for that. But I > couldn't understand how it estimates loss packets. > could you give me an example? I think that the data loss can occur at two levels: at the physical layer, the leased line, and at the IP/TCP/UDP level. The physical layer should be able to detect the data loss and retransmit the data, so upper layer will not even notice that there have been retrsnamission (except that there may be some delay). Of course TCP will also detect when something goes wrong and retransmit the data (UDP does not retransmit the lost data, this is left to the application). TCP/UDP packet loss are from end to end: from one computer to another computer. While I presume you are more interested in the data loss specific to the leased line (to ask your telco to improve their service). For IP/TCP/UDP level, there are many counters that keep a log of what is being lost. These are accessible through SNMP. At the leased line level, it really depends on what kind of leased line you are using and what data the "modem" can give you. Best regards, Olivier