On Friday 22 Feb 2013 14:36:22 Helmut Jarausch wrote: > On 02/22/2013 02:55:07 PM, Mick wrote: > > On Friday 22 Feb 2013 08:04:38 Helmut Jarausch wrote:
> > > When copying data from one machine to the other one I see varying > > > speeds from only 0.5 Mbits/s up to > > > more than 20 Mbits/s. I have no idea why it is so slow some times. > > > There are no other wireless devices nearby. > > > > Where do you see these transfer speeds? On the wired machine, or on > > the > > wireless machine? > > > > What do you use to check the transfer speed? > > One tool is ttcp which is very similar to netcat and this concerns me > most. > The other tool is a remote webserver for measure internet speed I suggest that you troubleshoot speeds across your LAN first, before you look at connections across the Internet which tend to be less consistent. > > Do the speeds go up when you used a Cat5e cable at full duplex? > > The PC which is wired doesn't have those problems since I can transmit > data from > my remote office machine at the highest possble rate which is specified > by my > internet provider. What I'm saying is: When you connect BOTH machines to your router with cat5e cables does the performance improve? I didn't know that you were using ttcp and was trying to eliminate other bottlenecks, e.g. storage caching, or drive controller problems if you were transferring a file. > > Have you scanned for access points to be absolutely sure that there > > are no > > other wireless devices, or APs? > > > > Do you use encryption? > > Yes, but since I do get optimal performance "some time" I don't think > this matters. Right, inconsistent performance could be due to interference, rather than someone free-riding your open WiFi network. > > What frequency and channel are you on and have you tried to change > > channel/frequency? (some domestic devices like cordless phones, > > wireless > > earphones, bluetooth, microwaves, perimeter sensors, etc. can cause > > co-channel > > and adjacent channel interference and/or force sharing of the > > bandwidth). This may eliminate interference problems, but only if concentrated on a particular frequency. Broadband transmissions will still interfere. You could try moving your laptop around the premises to see if you can spot some device/appliance that may be causing this. > > Are both machines and the router's LAN on the same MTU? > > Sorry, what's "MTU" ? http://en.wikipedia.org/wiki/Maximum_transmission_unit I was trying to see if there is a mismatch which may cause excessive fragmentation. -- Regards, Mick
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