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