WRT54G cuts my bandwidth in half

slowbiz

slowbiz

2[H]4U
Joined
Aug 24, 2004
Messages
2,457
Linksys support = shit.

Okay, so this is the second WRT54G (v6) I've had. I returned the first one because of this problem that I'm having, and clearly it's something in the settings. The firmware is the most up to date stuff on there. I'm using wireless channel 11. The beacon interval and RTS threshold settings have been adjusted as per Linksys support. The signal strength is excellent at 54Mbps. I do live in an apartment, but I've got WPA turned on. Also, I've got a cordless phone, but it's 5.4GHz.

HOWEVER when I go to http://www.speedtest.net, I'm getting like 3.5MB down and .3MB up. If I'm using a wired connection, it's 10MB down and 1.5MB up. That's what I'm paying for.

WTF? I don't know why I didn't just ask you guys first.
 
WPA kills wireless speed, its the price you pay for wireless "security." It is unlikely that you will ever achieve wired performance with wireless.
 
That makes no sense though. I'm connected to the thing with a 54Mbps connection. Surely I should be able to squeeze 10 out of the 54 that I have going.
 
WPA has less overhead than WEP.

If possible, return that v6 POS. Less RAM, less flash, just not that good of a router. The bean counters got involved and tried to make the WRT54G cheaper to make, thus it isn't as good.
 
Interesting... I have a WRT54GC and can only get about half of the 6 Mbps I'm paying for through a wireless connection. I have no problems when wired. It seems broken if it can't manage 6 Mbps out of a possible 54.
 
In related news, wireless sucks. "54 Mb/s" is marketing. At best you'll get around 20 Mb/s real throughput via standard 802.11g.

While there are several potential problems here -- e.g. interference, running out of steam processing WAN filtering together with wireless encryption, protocol quirks in wireless, one feature that has helped me with this problem is TCP window scaling.

So the reverse conjecture (this solved the problem, so what was the problem?) goes that wireless adds additional latency, and at higher bandwidth, this creates a larger bandwidth-delay product. A typical solution for this is window scaling. Hopefully Vista will automate some of this stuff for us, but in the meanwhile, here's what I did:

Add key Tcp1323Opts and set it to 1
Add key TcpWindowSize and set it to 146000

Here's some more on the settings:
http://www.speedguide.net/read_articles.php?id=157

You could spend a few days on variations on these options, and not necessarily help matters, so I'd start with keeping it simple and doing the least possible. The speedguide has a different suggestion (as does everywhere else) for the TcpWindowSize. I have nothing against their suggestion; try it first if you like.

You can find more on this from Microsoft directly (which is a better source), but in a brief look, I didn't find anything as concise as speedguide's.

I don't have a really high-speed internet service for testing this further, but I was able to see my wireless download speed go from around 2.5-3.5 Mb/s (depending on the testing tool) up to my wired max, around 4.3 Mb/s.
 
Linksys is shit. My wrt54g finaly conked out. I am replacing it today with a Buffalo.
 
underdone said:
could you explain what window scaling is?
Click to expand...

TCP window scaling is a part of TCP window sizing -- the scaling feature basically allows the TCP window size to go higher than 64 KB. This is in RFC 1323, which is why the Tcp1323Opts setting is required above.

Here's one of many online sources that try to explain some of this stuff; this one has animations.

http://www.kehlet.cx/articles/99.html

Some more pictures here:

http://www.pcca.org/standards/architecture/tcp_window_size.pdf
 
You must log in or register to reply here.
Back
Top