From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx03.uni-tuebingen.de (mx03.uni-tuebingen.de [134.2.5.213]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 89A923B2A4 for ; Wed, 9 Mar 2022 12:39:11 -0500 (EST) Received: from [192.168.178.25] (ip-109-193-155-191.um39.pools.vodafone-ip.de [109.193.155.191]) by mx03.uni-tuebingen.de (Postfix) with ESMTPSA id DB5DF20CA7EA; Wed, 9 Mar 2022 18:39:09 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 mx03.uni-tuebingen.de DB5DF20CA7EA DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=uni-tuebingen.de; s=20211202test; t=1646847550; bh=cXMlEXPH7DCVq/bvHjIf0YHZV2iwGDxGP6XeSuhIuGg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=rfYMDdbuiyQT6GZr1qqgduTlA/0EHixC0I2zHUgXYKY7pio1lu2vHFf3kovI1xdZq DSMmYPQ47nbmSBZpLztVxMjq+44JKW+EvBLF4qdnBHDWW7RWT7BpO1aiZMf16DR2wq UdO7SCbTgVzTN+Hz6hp/MUeyh0Rn4SvfElT/4u7whpyEzVUSSE9ARSCUGVyDPPD/nz ydQ7u70IypiGyOJbKM5cY2iFrfakPl0jLL+MMv+4cU6Nct0fR4afh3JU8ntuPEu6/c Mmu2OmGKJxtVtG4X5vXANFB0frwjqmgFyPOC7asj+QN7LTUwZB1YFyyvQAalr9qkfV LWi4HpGpBEGSg== Message-ID: <5a8b6b4a-7f15-3f08-56b5-9e04773271bb@uni-tuebingen.de> Date: Wed, 9 Mar 2022 18:39:08 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 To: Jesper Dangaard Brouer , =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , bloat References: <87y21julxu.fsf@toke.dk> <9785d2cd-b164-deb4-4cbe-7d0fb356f16e@redhat.com> From: Michael Menth In-Reply-To: <9785d2cd-b164-deb4-4cbe-7d0fb356f16e@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Bloat] Up-to-date buffer sizes? X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Mar 2022 17:39:11 -0000 Hi all, I don't question the usefulness of AQMs for buffers - on the contrary. But what are up-to-date buffer sizes in networking gears, especially if AQMs are not in use? It's hard to find public and information about it. Anyone can point to a citable source? This raises also the question about the deployment of AQMs in networking infrastructure. I know it's already adopted by some OSs, but what about forwarding nodes? Any papers about it? Kind regards Michael Am 09.03.2022 um 18:24 schrieb Jesper Dangaard Brouer: > > > On 09/03/2022 17.31, Toke Høiland-Jørgensen via Bloat wrote: >> Michael Menth writes: >> >>> Hi all, >>> >>> are there up-to-date references giving evidence about typical buffer >>> sizes for various link speeds and technologies? >> >> Heh. There was a whole workshop on it a couple of years ago; not sure if >> it concluded anything: http://buffer-workshop.stanford.edu/program/ >> >> But really, asking about buffer sizing is missing the point; if you have >> static buffers with no other management (like AQM and FQ) you're most >> likely already doing it wrong... :) > > Exactly, I agree with Toke. The important parameter is the latency. > Or the packet sojourn time (rfc8289 + rfc8290) observed waiting in the > queue. > > The question you should be asking is: >  - What is the max queue latency I'm "willing" to experience on this link? > > Hint, you can then depending on the link rate calculate the max buffer > size you should configure. > > The short solution is: >  - just use fq_codel (rfc8290) as the default qdisc. > > --Jesper > > > -- Prof. Dr. habil. Michael Menth University of Tuebingen Faculty of Science Department of Computer Science Chair of Communication Networks Sand 13, 72076 Tuebingen, Germany phone: (+49)-7071/29-70505 fax: (+49)-7071/29-5220 mailto:menth@uni-tuebingen.de http://kn.inf.uni-tuebingen.de