Wireless significantly slower than ethernet?

[Jschultz]

My wireless connection over my comcast cable line seems to vary greatly between wireless and wired. Even though I pay for a 6 mb line, I still see between 800 kbps and 4 mbps on ethernet, but only 162 kbps on wireless. What am I doing wrong that it varies so much?

 

[MikeTheC]

Well, first off, 802.11b and 802.11g are each slower than 100baseT Ethernet, which is what typically comes off of any DSL or cable modem, and is also what typically comes off of any normal commercial router. That's just a fact of life.

As far as it being "significantly" slower, well...

100baseT means 100 Mb (that's Mega-bits) per second transfer.

802.11g has a theoretical top speed of 54Mbps. However, usually the top you'll ever see is about half (or less) than that. Let's be uber-conservative here and say 12Mbps is typical.

Now, your cable modem connection, like many others -- myself included -- is 6Mbps, which is roughly half of what you "should" get via wireless g. However, you have to remember other factors impact wireless. One is the amount of re-transmission of error'd packets due to interference and/or general signal loss. If you have any security settings turned on (which absolutely you *should* have turned on), they add to the "overhead", which then naturally consumes some of the bandwidth.

You need to keep an eye on your signal strength. A useful thing is also to know your computer's signal strength at your router's location (that is, how strong is the signal that your wireless router is seeing from your computer). Sadly, most commercial wireless router firmware lacks the capability of measuring and/or showing this. If you have a compatible router, you could always flash it to the DD-WRT Project's firmware which does contain this functionality.

In my own installation, I have a cable modem connected to a Buffalo WHR-HP-G54 wireless router, which then is wirelessly linked to a Linksys WRT54G v5 (both of which are running DD-WRT, btw) which is set up as a wireless <-> ethernet bridge, into which are connected my web server, an iMac G4, and (previously) also my PowerBook G4. I did this precisely because wireless is just too darned slow when trafficking in files. With the setup that I have, traffic between my two workstation Macs and my Debian Etch-running "Beige" Desktop G3/300 is 100Mbps, and only their respective links to the Internet are wireless.

Hopefully this helps. Maybe someone else here who's more familiar with wireless technology can comment further to give greater clarification.

 

[Jschultz]

Thank you for the info. I'm not far from my router at all, and my apartment is relatively small. I have my airport signal strength running at all bars, so I'm not quite sure what's going on.

 

[Makosuke]

This may not be helpful, but one thing that could cause major slowdowns like you're describing is interference, and I'm not sure that that's necessarily going to show up in the signal strength bar. You might make sure that "Use Interference Robustness" is turned on, and if that doesn't help, maybe try manually cycling through a few different channels on the router to see if that makes any difference.

Do you have two computers around? If so, transferring a file from a wireless one do a wired one will allow you to confirm the speed of the connection--if THAT works fine, then it's an interaction between the wireless router and the cable modem (unlikely, but possible). If not, at least it's an easier test.