From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x232.google.com (mail-oi0-x232.google.com [IPv6:2607:f8b0:4003:c06::232]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 126DB3B2B0 for ; Sun, 12 Jun 2016 14:25:18 -0400 (EDT) Received: by mail-oi0-x232.google.com with SMTP id u201so52717640oie.0 for ; Sun, 12 Jun 2016 11:25:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=h0d2y9IZRNdvICmGu5A9gOrr1K6DEYoy+lw28vpzyzI=; b=0QYGgSmtlIpg1LdKTJWuq23BTiW9B/HybR8kkVW62DDWmFE+fCPgEiMlDLNgNosvDO IjDThIQziLPbp8vTqLRT6ErWIhMRKDm5afRJBqjr3MHeZ7CPxA5dHPNoWKWC8LJBlzaK AYZx2qFB/TwbZESERt0e33uKoRWto+MFd/Pc0VMctYyMcbanp0FUMhyCdjdO+HHICL25 nMPQvENDziTrzcirX/w2Xww1RnntIIQNQgL+FfV7hQ0ThZWiD4xv/39xGdk2z+lJ5lUm inkNO/+j2+ogbtB93cYtA+NgwANvt4xsQcOeYCyXXyzNZ6MM6kXb7opRO8k23lYFJ/sU JImQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=h0d2y9IZRNdvICmGu5A9gOrr1K6DEYoy+lw28vpzyzI=; b=ltRwVjDnu9aXmQRVo5Z4yUCBlFU2Gr/wfCUbyTGhzk+yQU83sB1TvyV3Swtb7GCp3N P5e7E1xzQcB7AwA7KZZeERA7qrrwBLXcIaU4OF4R85yY32bcGcmopYH30LQvFZx7RIZF CUasXmyZVKDWR9+D5zuzI5XG9xKmKOCVg8PAfuhHeLfhStm0nq9Hf54rmFTqTe/YqnrW fhLpb0zylOSWbvUteM4+KDuZdI17/orRRWIF4PvdCXtRc6SSLGlVVv59hLP8m2lbhdfO 2SLYte70DSh18Kmp974wOphdehZlD0Pu/vYU7+6VDtuq5ThFChXceXFdXgdiO9JuI6Or V7Yg== X-Gm-Message-State: ALyK8tIsOnmCLMwT3m2WFQbq6FZIpZPDHAXE+/cQjJULKS59KsjGuMdBe3ZwFfDbXsy/dhpyhtfmbuDXg1xUPg== X-Received: by 10.202.108.19 with SMTP id h19mr6045157oic.69.1465755917492; Sun, 12 Jun 2016 11:25:17 -0700 (PDT) MIME-Version: 1.0 Received: by 10.157.16.115 with HTTP; Sun, 12 Jun 2016 11:25:17 -0700 (PDT) In-Reply-To: <151299a8-87ec-6a8a-b44b-9f710c31a46f@gmail.com> References: <151299a8-87ec-6a8a-b44b-9f710c31a46f@gmail.com> From: Benjamin Cronce Date: Sun, 12 Jun 2016 13:25:17 -0500 Message-ID: To: Noah Causin Cc: bloat Content-Type: multipart/alternative; boundary=001a1142e14aca276d053518e415 Subject: Re: [Bloat] Questions About Switch Buffering 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: Sun, 12 Jun 2016 18:25:18 -0000 --001a1142e14aca276d053518e415 Content-Type: text/plain; charset=UTF-8 Routers and firewalls are common to have AQMs because they mostly deal with a high to low bandwidth transition from LAN to WAN. Internal networks rarely have bandwidth issues and congestion only happens when you don't have enough bandwidth. LANs are relatively easy to increase bandwidth. Either by binding ports or purchasing 10Gb or 40Gb links. If you have a 1Gb link from your LAN to your router and it's getting bloat issues, I recommend purchasing a 10Gb uplink to your switch. AQMs are difficult to do at line rate, even in hardware, and it will almost always be the case that a faster port is cheaper and better than implementing an AQM in the switch. One paper that I read was saying our rate of bandwidth is increasing much faster than our ability to process packets. Moving data is relatively easy compared to doing branching logic against the data. The paper went one to review several 400Gb ports, most of which actually were capable of doing near line rate 400Gb, but even the best one, once you enabled a simple strict priority QoS nose-dived down to 150Gb. It's becoming a physics issue. In order to do complex logic, you need more transistors, and that is at odds with moving the data faster through the system. At high link speeds in the future, think 1Tb+, QoS may have to go away unless we find some sort of photonic processing breakthrough. The good news is it seems like there's no ceiling on the amount of bandwidth we can push over fiber. On Sun, Jun 12, 2016 at 12:44 PM, Noah Causin wrote: > I have some questions about switch buffering. > > Are there any good switches that have modern AQMs in them like fq_codel? > > Also, If a home router has a built-in switch, is the buffering controlled > by the AQM, or do the switches have their own internal buffering that takes > precedence? > > The scenario I am thinking of is two ports trying to feed data out of a > single port on a switch. > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat > --001a1142e14aca276d053518e415 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Routers and firewalls are common to have AQMs because they= mostly deal with a high to low bandwidth transition from LAN to WAN. Inter= nal networks rarely have bandwidth issues and congestion only happens when = you don't have enough bandwidth. LANs are relatively easy to increase b= andwidth. Either by binding ports or purchasing 10Gb or 40Gb links. If you = have a 1Gb link from your LAN to your router and it's getting bloat iss= ues, I recommend purchasing a 10Gb uplink to your switch. AQMs are difficul= t to do at line rate, even in hardware, and it will almost always be the ca= se that a faster port is cheaper and better than implementing an AQM in the= switch.

One paper that I read was saying our rate of ba= ndwidth is increasing much faster than our ability to process packets. Movi= ng data is relatively easy compared to doing branching logic against the da= ta. The paper went one to review several 400Gb ports, most of which actuall= y were capable of doing near line rate 400Gb, but even the best one, once y= ou enabled a simple strict priority QoS nose-dived down to 150Gb. It's = becoming a physics issue. In order to do complex logic, you need more trans= istors, and that is at odds with moving the data faster through the system.=

At high link speeds in the future, think 1Tb+, Qo= S may have to go away unless we find some sort of photonic processing break= through. The good news is it seems like there's no ceiling on the amoun= t of bandwidth we can push over fiber.

On Sun, Jun 12, 2016 at 12:44 PM, Noah Cau= sin <n0manletter@gmail.com> wrote:
I have some questions about switch buffering.

Are there any good switches that have modern AQMs in them like fq_codel?
Also, If a home router has a built-in switch, is the buffering controlled b= y the AQM, or do the switches have their own internal buffering that takes = precedence?

The scenario I am thinking of is two ports trying to feed data out of a sin= gle port on a switch.
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