On Sun, May 21, 2017 at 02:18:06PM -0000, Dan Purgert wrote: > Mark Fletcher wrote: > > > > My home network consists of 2 Debian machines, one Jessie and one > > Stretch, an LFS mini-ITX machine acting as my firewall, another LFS > > laptop that is connected only occasionally, a Windows 8.1 laptop, 3 > > iPhones of varying ages, 2 iPads, 1 Android tablet device, a couple of > > other proprietary tablets and a Buffalo Linkstation that provides most > > of the connectivity. > > Quick google doesn't show any "Linkstation" devices with more than one > ethernet port (much less wifi). Do you perhaps mean an "Airstation"? > Could you provide the model number, so we can look it up?
Thanks everyone for your suggestions. I"m now travelling for business, hence the delay in replying. I will check on my return at the end of the week and reply. Mark > > > [...] > > I have my doubts about cross-LAN throughput. For example, as I write I > > am using WinSCP on the Windows 8.1 laptop to copy a movie file from my > > Jessie box to the laptop. (The movie concerned is not copyright before > > anyone asks). The Jessie box is connected to the LinkStation by wired > > ethernet, and the Windows 8.1 laptop by WiFi. I am getting a transfer > > rate consistently across the life of the connection of 880KB/s. I'd > > expect it to be a lot faster than that. I checked the WinSCP software is > > capable of limiting the connection speed, but is set not to. > > > 880KB (we'll call it 1 MB) / kilobytes per second is about 8 megabits > per second (1 byte = 8 bits). 8 mbit is a touch low (but in the > "range") of what you can expect from 802.11g. 802.11n may also fall > this low, but generally only when there's interference / poor signal. > > A VERY rough rule of thumb is that on a perfectly clear channel, you can > expect your throughput to be approximately 1/3 to 1/2 of the "on the > box" speed (so 802.11g - 54mbit/sec yields roughly 18-24 mbit) for ONE > device connected to the AP. > > >From there, you have to divide up the available throughput by number of > clients (i.e. a given wifi client's speed is 1/n, assuming that all > clients are using the same technology). So if your wifi was *perfect* > for 802.11g, and one client got 24 mbit -- 2 clients would average 12 > mbit each, 3 would average 8, and so on. > > In addition to "your clients", you have to contend with neighbors on the > same channels (who add to the 1/n throughput troubles). 5 GHz helps > here, as it's less likely that the clients in your home will see the 5 > GHz signal from your neighbors, even if you are on the same channel. > > > [...] > > > > I'd like to be able to diagnose what's going on here, why the transfer > > was so slow. Any recommendations for tools I should research? I am very > > willing to read man pages etc, but am a bit lost where to start. Google > > gave me a lot of Windows-based stuff which I could look into but I would > > prefer to use Linux-based tools if possible. > > > > Pointers to tools I should research -- and even better, links to good > > tutorials on those tools if you know any -- would be much appreciated. > > iperf would be a solid start. Run it from one machine to another (e.g. > the wireless laptop to a wired desktop). Don't try running it on the > router / access point / switch (if you have any of those), as iperf can > be resource intensive, so you "lose" a lot of speed due to their > processor not being able to keep up with the packet generation. > > Also check your wifi channel usage -- 2.4 GHz should be on channel 1, 6, > or 11 (if you're somewhere where 13 is allowed, you could try that too). > If you use any other channel (2-5 or 7-10), you're going to be getting a > lot of interference (and throughput losses) from your neighbors. > > > -- > |_|O|_| Registered Linux user #585947 > |_|_|O| Github: https://github.com/dpurgert > |O|O|O| PGP: 05CA 9A50 3F2E 1335 4DC5 4AEE 8E11 DDF3 1279 A281 >
