Friday, September 16, 2005

When a Wireless Adapter Is Not a Wireless Bridge

Several weeks ago I was looked for a way to provide my desk laptop with 802.11g connectivity. Sometimes I operate two or three systems on my desk. I thought it might be helpful to purchase an 802.11g wireless bridge. Using the bridge, I could connect those multiple systems via Ethernet to the bridge, and have the bridge speak 802.11g to my Linksys wireless access point.

I had not had good experiences with 802.11b Linksys WET11 bridges, so I turned to NetGear. I noticed they sold the WGE111 54 Mbps Wireless Game Adapter pictured upper left. I thought, "I can buy that, connect it to a hub, and then connect wired systems to the hub." With a price around $50 after rebate this seemed like a great deal, especially compared to the NetGear WGE101, for $80 or more, pictured upper right. A competing product from Linksys, the WET54G costs about $120. (I do like the WET54GS5 that has a five port switch built into it, but that costs about $150.)

It turns out that the WGE111 will not support my requirements unless I trick it. The WGE111 appears to keep track of the MAC address of the wired side device and will not let more than one system connect to the wireless network at a time. The way to fool the WGE111 to support more than one wired client is to put the wired systems behind a small NAT gateway router. I guess I got what I paid for!

Incidentally, I perused the reference manual for the WET54GS5 and learned it supports one-to-one port mirroring. In other words, you can copy the traffic on one port to one other monitoring port. That is a nice way to gain access to traffic in a switched environment. I would like to see similar features in other low-end switches.

For the moment I don't plan to buy any wireless bridges. It would be nice if I could use the WRT54G, the cheap ($60 or less) wireless workhorse, in bridging mode. I found a how-to that relies on third-party firmware; more details here. I might try this.

6 comments:

Erich said...

I have to say that I use two WRT54G's in a WDS setup similar to the guide you've mentioned. It works very well and I recommend the WRT54G's to anyone looking for a cheap AP/Router/Firewall that can do many things. You can even make the devices a Kismet drone!

http://www.renderlab.net/projects/wrt54g/index.html

Justin Mason said...

One bit of customer feedback -- I'd strongly recommend avoiding NetGear hardware.

Before I replaced it with a reflashed Linksys WRT54G, I was using a NetGear MR814 on my home network. It was atrocious.

It hung on average once a day, requiring a (manual) power-cycle to recover; dropped SSH and VPN connections; had interoperability problems with other bits of 802.11b hardware; hung under heavy load; and, best of all, one of the less buggy firmware revisions even included code that DDOS'd the University of Wisconsin!

Stick with the reflashed WRT54G, IMO -- open source hackers know how to do this stuff, even if it requires a little RTFMing upfront ;)

WBG Links said...

I've had no problems with the WET11, though the "hack" of placing a router behind it for multiple connections is also necessary...come on, shouldn't a bridge act like a router also!?

:-)

Adam said...

The upgraded firmware for the WRT54G add alot of nice features not normally in an AP. I would recommend checking it out.

Anonymous said...

Adding another vote for the WRT54G option. I've been running mine as a bridge for a couple months now and have been very happy with the results. I have my desktop, xbox, tivo connected with no problems.

Anonymous said...

I've managed to deploy dozens of linksys wrt54g with third party firmware openwrt (www.openwrt.org), before that I've tried other third party firmware (sveasoft, hyperwrt etc), but openwrt is by far the most flexible firmware I've ever use, it allows you to make openwrt as a bridge, a router, wireless client, wireless access point, and the website contains helpfull information to setup one.