Wireless speed drops

[David Timms]

Georgi Hristozov wrote:
> I'm having an odd problem with Fedora 10. I'm using the x86 version 
> (fully updated) on Toshiba Satellite A200. My network card is Intel 
> 3945ABG and I'm using 802.11g with WPA.
> 
> After a few minutes with this maximum speed of my home network 
> (20-23MBps), it suddenly drops to values around 1MBps and doesn't 
> increase again, no matter what I try. The only solution is to restart 
> Network Manager. After deactivating NM and trying wicd, the problem 
> persisted. And I was able to solve it by restarting wicd, like the case 
> with NM. Some people from the Bulgarian LUG suggested that it's from 
> iwl3945, because they have similar issues. But they don't have a 
> solution yet. Unfortunately, I don't see anything suspicious in the 
> logs.
Did you check /var/log/messages between the time it's working well, to 
when it starts to go slow ?
Does NM go through a disconnect, connected process ?

> Any ideas how can I debug this issue?
- With another wireless machine, can you prove to yourself that access 
rate stays high even when problem laptop goes slow ?

- Once troubled, does a WAP gateway restart help ?

- Does the laptop only have trouble with this WAP, ie test it with 
another WAP ?

- Could the wireless card be getting put in low power mode/asleep where 
waking doesn't working properly ?

- Are you using power suspend or sleep modes ?

- can a wired connection to the same network stay up and continually 
download at good wired rates (eg 60Mbps on 100M connection ?

- Is the wap a router as well ?

- are you using any peer-peer network apps on either wired or wireless 
parts of your network, or even the on the troubling laptop ?

- Does the WAP log show any trouble ?

- Are you moving too close or far away from the WAP ?

- Interference from too many 802.11 frequency devices like other WAPs, 
microwave, DECT cordless phones etc ?

- does the wireless tools like iwconfig etc show that the connection 
speed has been adjusted ?

- does it matter if your notebook is running of mains or battery ?

These are just random guesses really, since my 3945 on HP nx6320 works 
just fine, and continues to work when I take the notebook downstairs, 
some obstructions away. However, my WAP Netgear WTG624 needs a power 
reboot about every one-two weeks because it stops responding anymore, ie 
the client network cards (notebook and 802.11G mobile phone) can no 
longer connect.

DaveT.