From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bobcat.rjmcmahon.com (bobcat.rjmcmahon.com [45.33.58.123]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 759B33B2A4 for ; Sun, 19 Feb 2023 19:02:51 -0500 (EST) Received: from mail.rjmcmahon.com (bobcat.rjmcmahon.com [45.33.58.123]) by bobcat.rjmcmahon.com (Postfix) with ESMTPA id B8CD71B258; Sun, 19 Feb 2023 16:02:50 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 bobcat.rjmcmahon.com B8CD71B258 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rjmcmahon.com; s=bobcat; t=1676851370; bh=2COr4OtXs1dI8fjqnwkeTtIDrE41SLcP529y/UxGsM4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=E/XI6TjNlvmFZv+MufRGM1QcimnVXIXIMDKRWVc4TwAJY3bRusdvhVhDlo3KndeZ8 Icvaqm8mKPUcA3nMe8CduCykQgdqF1fjXmppWUmr4xdfw4yoBC6y5VqyB3NJixQE7l 1C/JTvh7SVzbdrC8A6Jqfde4a1q7wr5s/XzQvjWA= MIME-Version: 1.0 Date: Sun, 19 Feb 2023 16:02:50 -0800 From: rjmcmahon To: rjmcmahon Cc: Dave Taht , Rpm In-Reply-To: <3f89e35c27c144bbe4b6c8f2128e1557@rjmcmahon.com> References: <26ac4e4e00b1d0f20c816630fafb7e58@rjmcmahon.com> <1209c1b2fb917edc8bf33a73782823bd@rjmcmahon.com> <3f89e35c27c144bbe4b6c8f2128e1557@rjmcmahon.com> Message-ID: <53b644b95d0901ef52f16bf53914517c@rjmcmahon.com> X-Sender: rjmcmahon@rjmcmahon.com Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Rpm] Almost had a dialog going with juniper... X-BeenThere: rpm@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: revolutions per minute - a new metric for measuring responsiveness List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Feb 2023 00:02:51 -0000 Here, look at this. Designed as a WiFi aggregation device. https://www.arista.com/en/products/750-series It supplies 60W PoE and claims support for 384 ports. Oh, the max distance per PoE AP is 100 meters. That's insane as a power source and the 100M distance limit is not viable. Our engineering needs to improve a lot. Bob > Cisco's first acquisition was Crescendo. They started with twisted > pair and moved to Cat5. At the time, the claim was nobody would rewire > corporate offices. But they did and those engineers always had an AC > power plug nearby so they never really designed for power/bit over > distance. > > Broadcom purchased Epigram. They started with twisted pair and moved > to wireless (CMOS radios.) The engineers found that people really > don't want to be tethered to wall jacks. So they had to consider power > at all aspects of design. > > AP engineers have been a bit of a Frankenstein. They have power per AC > wall jacks so the blast energy everywhere to sell sq ft. The > enterprise AP guys do silly things like PoE. > > Better is to add CMOS radios everywhere and decrease power, > inter-connected by fiber which is the end game in waveguides. Even the > data centers are now limited to 4-meter cables when using copper and > the energy consumption is through the roof. > > Bob >> On Sun, Feb 19, 2023 at 3:37 PM rjmcmahon >> wrote: >>> >>> A bit off topic, but the AP/client power asymmetry is another design >>> flaw similar to bloat. >> >> It makes no sense to broadcast at a watt when the device is nearby. I >> think this is a huge, and largely unexplored problem. We tried to >> tackle it in the minstrel-blues project but didn't get far enough, and >> the rate controllers became too proprietary to continue. Some details >> here: >> >> https://github.com/thuehn/Minstrel-Blues >> >>> >>> Not sure why nobody is talking about that. >> >> Understanding of the inverse square law is rare. The work we did at >> google fiber, clearly showed the chromecast stick overdriving nearby >> APs. >> >> https://apenwarr.ca/diary/wifi-data-apenwarr-201602.pdf >> >> >>> https://www.youtube.com/watch?v=Ey5jVUXSJn4 >> >> Haha. >> >>> >>> Bob >>> > Their post isn't really about bloat. It's about the discrepancy in i/o >>> > bw of memory off-chip and on-chip. >>> > >>> > My opinion is that the off-chip memory or hybrid approach is a design >>> > flaw for a serious router mfg. The flaw is thinking the links' rates >>> > and the chip memory i/o rates aren't connected when obviously they >>> > are. Just go fast as possible and let some other device buffer, e.g. >>> > the end host or the server in the cloud. >>> > >>> > Bob >>> >> https://blog.cerowrt.org/post/juniper/ >>> >> >>> >> But they deleted the comment thread. It is interesting, I suppose, to >>> >> see how they frame the buffering problems to themselves in their post: >>> >> https://www.linkedin.com/pulse/sizing-router-buffers-small-new-big-sharada-yeluri/ >>> > _______________________________________________ >>> > Rpm mailing list >>> > Rpm@lists.bufferbloat.net >>> > https://lists.bufferbloat.net/listinfo/rpm > _______________________________________________ > Rpm mailing list > Rpm@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/rpm