From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ej1-x62d.google.com (mail-ej1-x62d.google.com [IPv6:2a00:1450:4864:20::62d]) (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 913F03B29D for ; Wed, 27 May 2020 13:16:35 -0400 (EDT) Received: by mail-ej1-x62d.google.com with SMTP id n24so29003317ejd.0 for ; Wed, 27 May 2020 10:16:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=3YxQwJDMZ1SVo10/P5trPOfGwaLOzy3XxFDODbviSjU=; b=e+RlwOxXv1+2xINIuj36gi1BBR0jAr6RHssg8xYX3SGrisJOZOU9RlenWiNFTI84aw B2V5qV5HrEJKpSGVrjiHv+BhHX+8lxq2P/WcnLUmJNuwnoeVxW0l7LFdB2iT8/7vTT1a 8cA/Zb/8/gZ7ri6p456DGrQ7HNkPK6+znHEJY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=3YxQwJDMZ1SVo10/P5trPOfGwaLOzy3XxFDODbviSjU=; b=jPx+CVLunzOppkDzpkbe1iZXK7mMZMRkZ+k/hFPl4/y37W/eMNNCFhN+LU4el3M+ww 5uZqqvoS9SAkoDl8jRAgJiOscuWOYCjv7v4wr6vDcJW9B8spQ6DrwOV2BGf+FRK8TmpZ fh9P/lt+0qLL/gFVbJAKnaJ/1ARyQFSNafOcCKjT7DGcFZ0bThB1ZFXDieBnqWZCZxbk uo/ZEKChBxQsQx116B8vLP60F3Z8DsO7C5NjYuCb0EyzwxcY9hzwWdTId2A6kpZSN8LX Cm2ePUnaa10DLp1lq6PTDHEvQ2nm2+8rCes/d92d2QugGoAWwmMKQpYPU1BlNKnez/QR SSnQ== X-Gm-Message-State: AOAM533qmb8qYEC+78dY0J8Nb5ThcEfbkHGXqvZZCdVDImrdTk9Zj0o9 SNM47Vi8v2DrxlC/Wr+UWLgZCz+vLUknGN1YFgkNbSeu X-Google-Smtp-Source: ABdhPJyoprS0uhie87KbWR5afbpxTax4KekYP8UzYa29abjGGHRjx/xFUbrxLvRjIq2GwRghDjigYepuSdF0RXKA41U= X-Received: by 2002:a17:906:194b:: with SMTP id b11mr6741355eje.159.1590599794475; Wed, 27 May 2020 10:16:34 -0700 (PDT) MIME-Version: 1.0 References: <4337569f-8df2-426f-013f-d9748f7695c1@smallnetbuilder.com> In-Reply-To: <4337569f-8df2-426f-013f-d9748f7695c1@smallnetbuilder.com> From: Bob McMahon Date: Wed, 27 May 2020 10:16:23 -0700 Message-ID: Subject: Re: [Make-wifi-fast] REPOSTED: SmallNetBuilder Article: Does OFDMA really work? Part 2 To: Tim Higgins Cc: Make-Wifi-fast Content-Type: multipart/alternative; boundary="000000000000bb0f2005a6a45f08" X-List-Received-Date: Wed, 27 May 2020 17:16:35 -0000 --000000000000bb0f2005a6a45f08 Content-Type: text/plain; charset="UTF-8" I would make a small packet run too. For iperf2 use -l 40 and -b 20000pps and vary the pps number. I would hope that OFDMA would increase this. Also, don't forget about jitter - the derivative of latency. Some protocols care more about jitter than they do latency. I'd look into measuring the actual latency and jitter of the traffic vs using a ping as a proxy. This will be supported in iperf 2.0.14 using the write (server) side clock and --write-ack. Better though is to synchronize the clocks and use one way trip times. While I like to synchronize the realtime clocks to the GPS atomic clock as the reference, using PTP and synchronizing to a common reference of any PC oscillator may be good enough. PTP stats will give you errors and corrections and per the corrections one can get an idea of the error. Thanks for posting. I really don't think OFDMA is going to affect such large latencies in a noticeable manner. I think it will be the ultra low latencies or near zero queuing that will matter. For data center switches this is driven mostly by high frequency traders. For WiFi it's going to be newer games with VR/AR. Those latencies are going to need to be very low compared to today's use cases. my $0.02, Bob On Wed, May 27, 2020 at 7:37 AM Tim Higgins wrote: > Tests have been redone and article is back up. > =========================== > Hi All, > > This article uses the benchmark test described in Part 1 to test 6 Wi-Fi > consumer routers. Results are not impressive. > > https://www.smallnetbuilder.com/wireless/wireless-features/33223-does-ofdma-really-work-part-2 > > =========== > Tim > _______________________________________________ > Make-wifi-fast mailing list > Make-wifi-fast@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/make-wifi-fast --000000000000bb0f2005a6a45f08 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I would make a small packet run too. For iperf2 use -l 40 = and -b 20000pps and vary the pps number. I would hope that OFDMA would incr= ease this.=C2=A0

Also, don't forget=C2=A0about jitter - the der= ivative of latency. Some protocols care more about jitter=C2=A0than they do= latency.

I'd look into measuring the actual=C2=A0latency and j= itter of the traffic vs using a ping as a proxy. This will be supported in = iperf 2.0.14 using=C2=A0the write (server) side clock and --write-ack.=C2= =A0 Better though is to synchronize the clocks and use one way trip times. = While I like to synchronize the realtime=C2=A0clocks to the GPS atomic cloc= k as the reference, using PTP and synchronizing=C2=A0to a common reference = of any PC oscillator may be good enough. PTP stats will give you errors and= corrections and per the corrections one can get an idea of the error.
<= br>Thanks=C2=A0for posting. I really don't think OFDMA is going to affe= ct such large latencies in=C2=A0a noticeable manner. I think it will be the= ultra low latencies or near zero queuing that will matter.=C2=A0 For data = center switches this is driven mostly by high frequency traders. For WiFi i= t's going to be newer games with VR/AR. Those latencies are going to ne= ed to be very low compared to today's use cases.

my $0.02,
Bob

On Wed, May 27, 2020 at 7:37 AM Tim Higgins <tim@smallnetbuilder.com> wrote:
=20 =20 =20
Tests have bee= n redone and article is back up.
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D
Hi All,

This article uses the benchmark test described in Part 1 to test 6 Wi-Fi consumer routers. Results are not impressive.
https://www.smallne= tbuilder.com/wireless/wireless-features/33223-does-ofdma-really-work-part-2=

=20
=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D
Tim
_______________________________________________
Make-wifi-fast mailing list
M= ake-wifi-fast@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/make-wif= i-fast
--000000000000bb0f2005a6a45f08--