From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tuna.sandelman.ca (unknown [IPv6:2607:f0b0:f:3:216:3eff:fe7c:d1f3]) by huchra.bufferbloat.net (Postfix) with ESMTP id 3883721F168; Wed, 28 Nov 2012 13:45:10 -0800 (PST) Received: from obiwan.sandelman.ca (desk.marajade.sandelman.ca [209.87.252.247]) by tuna.sandelman.ca (Postfix) with ESMTP id E1F2920168; Wed, 28 Nov 2012 16:47:01 -0500 (EST) Received: by obiwan.sandelman.ca (Postfix, from userid 179) id 19F9863A8E; Wed, 28 Nov 2012 16:44:42 -0500 (EST) Received: from obiwan.sandelman.ca (localhost [127.0.0.1]) by obiwan.sandelman.ca (Postfix) with ESMTP id 0515D63A8C; Wed, 28 Nov 2012 16:44:42 -0500 (EST) From: Michael Richardson To: Eric Dumazet In-Reply-To: <1354128663.14302.488.camel@edumazet-glaptop> References: <20121127224915.GM2474@linux.vnet.ibm.com> <20121128002710.GS2474@linux.vnet.ibm.com> <50B5887C.7010605@pollere.com> <20121128043838.GX2474@linux.vnet.ibm.com> <20121128160133.GA16995@linux.vnet.ibm.com> <20121128174440.GD2474@linux.vnet.ibm.com> <7700.1354127857@obiwan.sandelman.ca> <1354128663.14302.488.camel@edumazet-glaptop> X-Mailer: MH-E 8.3; nmh 1.3-dev; XEmacs 21.4 (patch 22) X-Face: $\n1pF)h^`}$H>Hk{L"x@)JS7<%Az}5RyS@k9X%29-lHB$Ti.V>2bi.~ehC0; <'$9xN5Ub# z!G,p`nR&p7Fz@^UXIn156S8.~^@MJ*mMsD7=QFeq%AL4m Sender: mcr@obiwan.sandelman.ca Cc: John Crispin , "codel@lists.bufferbloat.net" , "cerowrt-devel@lists.bufferbloat.net" , bloat Subject: Re: [Cerowrt-devel] [Codel] [Bloat] FQ_Codel lwn draft article review X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Nov 2012 21:45:10 -0000 >>>>> "Eric" == Eric Dumazet writes: >> >>>>> "Paul" == Paul E McKenney writes: Paul> You lost me on this one. It looks to me like Paul> net/sched/sch_fq_codel.c Paul> in fact does hash packets into flows, so FQ-CoDel is Paul> stochastic in the Paul> the same sense that SFQ is. In particular, FQ-CoDel can hash a thin Paul> session into the same flow as a thick session, which really is the Paul> birthday effect. >> >> Silly question from someone who should read more code, but... >> if one is hashing the packet to pick a flow bucket, shouldn't this hash >> occur before any application of address/port translation. ? (NAT) >> >> (Maybe I've just found out that IPv6 + CoDel will be a killer >> combination) Eric> Why would it be a killer ? I mean, it's a killer app :-) Eric> A NATed flow becomes another flow, with its own hash yes, but one loses the afinity to which internal host the flow belongs to, so it's harder to be "fair" to each host. going deeper into the packet is both expensive and is difficult to impossible given tunnels and NAT. The lack of NAT on IPv6 would make deeper classification easier for layer-two devices (DSL modems, etc), and the IPv6 flow label would also contribute significantly to making this easier. Consider a future scenario where there are the following streams easily identified: 1) IPv4 packets less than 128 bytes. 2) IPv6 packets > 128 bytes. *) IPv6 flows identified by flow label In such a situation, IPv6 becomes the choice for interactive video. -- ] He who is tired of Weird Al is tired of life! | firewalls [ ] Michael Richardson, Sandelman Software Works, Ottawa, ON |net architect[ ] mcr@sandelman.ottawa.on.ca http://www.sandelman.ottawa.on.ca/ |device driver[ Kyoto Plus: watch the video then sign the petition.