Re: Throughput riddle
On Fri, 18 Mar 2016 13:25:04 -0600 (MDT)
"John L. Ries" <jries@salford-systems.com> wrote:
> Forgot to mention:
>
> I use NetworkManager on the main box to configure the connection with
> the NAS (if you're using something else, consult your documentation).
> Under "IPv4 settings" (or IPv6 if you prefer), select "Link-local only"
> as the method. We expect that the NAS will do this automatically when
> it finds out the connection is point to point.
Thanks.
> On Friday 2016-03-18 12:44, John L. Ries wrote:
>
> >Date: Fri, 18 Mar 2016 12:44:30
> >From: John L. Ries <jries@salford-systems.com>
> >To: Celejar <celejar@gmail.com>
> >Cc: debian-user <debian-user@lists.debian.org>
> >Subject: Re: Throughput riddle
> >
> > I don't know if it will help, but I hook up my Iomega NAS directly to my
> > desktop machine with a regular cat 5/6 cable (each has two gigabit
> > Ethernet ports, so each can connect to the rest of my network, as well
> > as to each other) and that seems to help the throughput by a lot (but I
> > don't have any numbers for you). So if your NAS has an extra Ethernet
> > port, you might want to hook it up to your laptop when you're in the
> > same room with it and use your wifi interface to connect to your
> > network. Certainly, you should avoid connecting to your NAS over wifi
> > if you're using it heavily, as that will definitely slow things down (it
> > seems that a lot more handshaking is required to connect through the air
> > than through a physical cable).
> >
> > --------------------------|
> > John L. Ries |
> > Salford Systems |
> > Phone: (619)543-8880 x107 |
> > or (435)867-8885 |
> > --------------------------|
> >
> >
> > On Friday 2016-03-18 10:48, Celejar wrote:
> >
> >> Date: Fri, 18 Mar 2016 10:48:24
> >> From: Celejar <celejar@gmail.com>
> >> To: debian-user <debian-user@lists.debian.org>
> >> Subject: Throughput riddle
> >>
> >> Hi,
> >>
> >> I'm trying to understand the throughput across the different links of
> >> my little home network, and am perplexed by the measured wireless
> >> throughput.
> >>
> >> The three main devices I'm interested in:
> >>
> >> Router: Buffalo WZR-HP-G300NH running OpenWrt (Chaos Calmer 15.05).
> >> Gigabit WAN and LAN, 802.11bgn wireless.
> >>
> >> https://wiki.openwrt.org/toh/buffalo/wzr-hp-g300h
> >>
> >> Laptop: Thinkpad T61 running Jessie 8.3. Gigabit ethernet, 802.11abgn
> >> wireless.
> >>
> >> NAS: Seagate GoFlex Net [STAK100] runninng Debian Jessie 8.3.
> >>
> >> https://archlinuxarm.org/platforms/armv5/seagate-goflex-net
> >>
> >> All throughput measurements taken with iperf (run three times and using
> >> the median result), unless specified otherwise. These first results are
> >> with the laptop connected to the router via cat5:
> >>
> >> Laptop - NAS: ~874 Mbps.
> >>
> >> I suppose this is close enough to the gigabit theoretical max, and there isn't
> >> any significant bottleneck.
> >>
> >> Router - NAS: ~217 Mbps
> >> Router - laptop: ~198 Mbps
> >>
> >> Here the router CPU is apparently the bottleneck (top shows close to
> >> 100% CPU utilization by iperf for at least part of the 10 second iperf
> >> runs). I suppose that this is due to the bits needing to be copied out
> >> of the kernel networking stack into iperf's userspace memory, or
> >> something like that. I don't understanding why the NAS seems to be
> >> doing better, but I suppose it could be an artifact of the data.
> >>
> >> Here's the part that baffles me - these are with the laptop connected
> >> to the router wirelessly:
> >>
> >> Laptop - router: ~11.8 Mbps
> >>
> >> These numbers actually exhibit significant variance, but they're
> >> generally at least this much, and at most about 15-20 Mbps.
> >>
> >> Laptop - NAS: ~14.7 Mbps
> >>
> >> Once again, these numbers vary widely, but are in line with the laptop
> >> - router numbers.
> >>
> >> But here's the kicker: Ookla's speedtest (run on the laptop with
> >> speedtest-cli) shows 29.01/5.89 (d/u), and this is fairly consistent.
> >> I'm paying Comcast for 25/5, and they apparently provision at
> >> 31.25/6.25, so I'm getting quite close to the theoretical max, even
> >> when the laptop is connected to the router wirelessly. Additionally,
> >> various Android phones also get close to the Comcast provisioned max
> >> when connecting wirelessly to the router.
> >>
> >> So the wireless link can apparently push at least 30 Mbps or so, so why
> >> are my local wireless throughput numbers so much lower?
> >>
> >> I was originally using one of the common 1/6/11 channels, and I switched
> >> to 3 since I saw a lot of other stations on those channels. This may
> >> have resulted in some improvement, but I'm still stuck locally as
> >> above. What's the explanation for this - how can I possibly be getting
> >> much better throughput to servers tens of miles away than to my local
> >> stations? Does iperf somehow work fundamentally differently from
> >> speedtest? If so, which is a better representation of actual throughput?
> >>
> >> Celejar
> >>
> >>
> >
> >
Celejar
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