From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-24-ewr.dyndns.com (mxout-025-ewr.mailhop.org [216.146.33.25]) by lists.bufferbloat.net (Postfix) with ESMTP id CCFC72E0101 for ; Sat, 12 Mar 2011 22:55:00 -0800 (PST) Received: from scan-22-ewr.mailhop.org (scan-22-ewr.local [10.0.141.244]) by mail-24-ewr.dyndns.com (Postfix) with ESMTP id 32AC55D4031 for ; Sun, 13 Mar 2011 06:55:00 +0000 (UTC) X-Spam-Score: -15.5 (---------------) X-Mail-Handler: MailHop by DynDNS X-Originating-IP: 171.71.176.72 Received: from sj-iport-3.cisco.com (sj-iport-3.cisco.com [171.71.176.72]) by mail-24-ewr.dyndns.com (Postfix) with ESMTP id F1B4E5D401F for ; Sun, 13 Mar 2011 06:54:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=fred@cisco.com; l=952; q=dns/txt; s=iport; t=1299999295; x=1301208895; h=subject:mime-version:from:in-reply-to:date:cc:message-id: references:to:content-transfer-encoding; bh=cwiYorllB2cXMwwVVNZvDDLMBrv1/Oeocjve3Y3hrdg=; b=XSCHKjaB+gHIy0qQCyOOJahDUbOCZkKRP/InkAJBYkSUrQSYCDey+3XS FWrI/KlcZBSHez10FrWCecqLe9+txzvfAxIY3FVIEXufjI3dx37PP/IyK wEflzxQqJE5RMf9D3n+9jnIaHlc3nRMfQKmqvN8gUafl/voTAbdWQRsM3 A=; X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEAJr4e02tJXHA/2dsb2JhbACmRHekRZplhWIEhSuHJ4NO X-IronPort-AV: E=Sophos;i="4.62,310,1297036800"; d="scan'208";a="277501493" Received: from rcdn-core2-5.cisco.com ([173.37.113.192]) by sj-iport-3.cisco.com with ESMTP; 13 Mar 2011 06:54:55 +0000 Received: from stealth-10-32-244-219.cisco.com (stealth-10-32-244-219.cisco.com [10.32.244.219]) by rcdn-core2-5.cisco.com (8.14.3/8.14.3) with ESMTP id p2D6snb5024818; Sun, 13 Mar 2011 06:54:54 GMT Received: from [127.0.0.1] by stealth-10-32-244-219.cisco.com (PGP Universal service); Sat, 12 Mar 2011 22:54:54 -0800 X-PGP-Universal: processed; by stealth-10-32-244-219.cisco.com on Sat, 12 Mar 2011 22:54:54 -0800 Mime-Version: 1.0 (Apple Message framework v1082) From: Fred Baker In-Reply-To: <4A5D7592-685F-45CC-9429-CE7FC1A289B5@gmail.com> Date: Sat, 12 Mar 2011 22:54:39 -0800 Message-Id: References: <16808EAB-2F52-4D32-8A8C-2AE09CD4D103@gmail.com> <08621605-30D1-4916-82EE-A4219A653ACD@cisco.com> <4A5D7592-685F-45CC-9429-CE7FC1A289B5@gmail.com> To: Jonathan Morton X-Mailer: Apple Mail (2.1082) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Cc: bloat@lists.bufferbloat.net Subject: Re: [Bloat] Measuring latency-under-load consistently X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 13 Mar 2011 06:55:01 -0000 On Mar 12, 2011, at 3:03 PM, Jonathan Morton wrote: >=20 > On 13 Mar, 2011, at 12:21 am, Fred Baker wrote: >=20 >> At the risk of sounding like someone mentioning a product, let me = mention a product. This assumes, of course, that you're using Cisco = equipment. But it allows you to measure delay (how long does it take to = get from here to there), jitter (first derivative of delay/dt), and = packet loss. >=20 > Ping does most of this, and is available on your actual computer. A = little post-processing of the output gives you jitter, if it doesn't = supply that natively. >=20 > The point is, the existing tools don't typically measure latency = *under load*. Actually, SAA uses ping, and is intended precisely to do it under load. = Ping is part of the existing traffic, and measures the RTT as = experienced by traffic following the same path that the ping does. Not sure exactly where you're going with that...=