From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rcdn-iport-1.cisco.com (rcdn-iport-1.cisco.com [173.37.86.72]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "rcdn-iport.cisco.com", Issuer "HydrantID SSL ICA G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 4240F21FBAD for ; Mon, 3 Aug 2015 07:11:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=2121; q=dns/txt; s=iport; t=1438611126; x=1439820726; h=from:to:subject:date:message-id:references:in-reply-to: content-transfer-encoding:mime-version; bh=23zj/YfhK4qs05c1YNAOtD48tsj5buAXiWI8JGMzvJc=; b=iqSkhckYQJVog232fTU+/d0fY/NxfjxASCRVjmLqRlNliThgQbjlLn4s 4opE5RmnwvwGxqHV44SYvBq0SU+t1oSb3NhCSPVCx6EwI+l1rPuJVPl3t ty7IzAu1+0no7/WavcMgE4G5hBwnQ7WzeK4mD7d8O5wXwugjkIUg91O2Z o=; X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A0D+BAAjdb9V/5RdJa1bGQEBAYJ+VGkGvi8fCoV5AoEqOxEBAQEBAQEBgQqEIwEBAQEDAQEBNzQXBAIBCBEEAQEBChQJBycBChQJCAIEARIIiCYNyksBAQEBAQEBAQEBAQEBAQEBAQEBAQEXi0+EVzgGgxKBFAWUeQGEeoRzhCWUHYNkJoIOHIFTb4FIgQQBAQE X-IronPort-AV: E=Sophos;i="5.15,601,1432598400"; d="scan'208";a="21035551" Received: from rcdn-core-12.cisco.com ([173.37.93.148]) by rcdn-iport-1.cisco.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 03 Aug 2015 14:11:35 +0000 Received: from XCH-RCD-018.cisco.com (xch-rcd-018.cisco.com [173.37.102.28]) by rcdn-core-12.cisco.com (8.14.5/8.14.5) with ESMTP id t73EBYfj029926 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=FAIL); Mon, 3 Aug 2015 14:11:34 GMT Received: from xch-rcd-018.cisco.com (173.37.102.28) by XCH-RCD-018.cisco.com (173.37.102.28) with Microsoft SMTP Server (TLS) id 15.0.1076.9; Mon, 3 Aug 2015 09:11:34 -0500 Received: from xhc-rcd-x03.cisco.com (173.37.183.77) by xch-rcd-018.cisco.com (173.37.102.28) with Microsoft SMTP Server (TLS) id 15.0.1076.9 via Frontend Transport; Mon, 3 Aug 2015 09:11:34 -0500 Received: from xmb-aln-x05.cisco.com ([169.254.11.9]) by xhc-rcd-x03.cisco.com ([173.37.183.77]) with mapi id 14.03.0248.002; Mon, 3 Aug 2015 09:11:33 -0500 From: "Bill Ver Steeg (versteb)" To: "Steinar H. Gunderson" , "bloat@lists.bufferbloat.net" Thread-Topic: [Bloat] came across an unexpected side-effect of bufferbloat Thread-Index: AQHQzfPl1tl0IVUPoEaN4rKGvBLfep36oYkA//+tjTA= Date: Mon, 3 Aug 2015 14:11:33 +0000 Message-ID: References: <20150803140054.GA5082@sesse.net> In-Reply-To: <20150803140054.GA5082@sesse.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [64.100.112.175] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [Bloat] came across an unexpected side-effect of bufferbloat 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: Mon, 03 Aug 2015 14:12:05 -0000 It is even worse than that - On some really crappy low end devices, applica= tions do not get a taste of the CPU if there is a packet to be sent. If the= re is always a packet to be sent, the SNMP daemon and/or some DOCSIS/DSL/FT= Tx tasks (and other application level tasks that need to interact with the = control plane) don't run. Eventually something weird happens, like a memory= leak or a dead-man timer and the box reboots. Clearly, this is sub-optima= l.=20 Fortunately, Darwinian pressures have made this type of device less prevale= nt in the marketplace. You can still run into some really poor CPE in the w= ild, though. Bill VerSteeg -----Original Message----- From: bloat-bounces@lists.bufferbloat.net [mailto:bloat-bounces@lists.buffe= rbloat.net] On Behalf Of Steinar H. Gunderson Sent: Monday, August 03, 2015 10:01 AM To: bloat@lists.bufferbloat.net Subject: Re: [Bloat] came across an unexpected side-effect of bufferbloat On Mon, Aug 03, 2015 at 11:53:40PM +1000, jb wrote: > While researching a little I came across a message on the Amazon=20 > support forums that said after 3 hours of uploading to Amazon, their=20 > cable modem would crash and reboot. The reason was that the SNMP the=20 > cable modem needed to stay healthy was timing out (due to the=20 > excessive latency induced by the continuous uploading). The author didn't= know it was bufferbloat, of course. FWIW, you don't need bufferbloat for this to fail. A classic thing with swi= tches (typically underbuffered rather than overbuffered!) is that when you = run the links full, the OSPF packets get dropped and eventually your link f= laps because the other side thinks you're down. This is one of the reasons why most L3 switches (well, anything that's adva= nced enough to do OSPF or the likes in the first place :-) ) have QoS at all: You need to protect your administrative traffic. /* Steinar */ -- Homepage: http://www.sesse.net/ _______________________________________________ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat