I installed a Linksys WRT54GS 802.11G access point (AP) and a Linksys WRE54G range expander (RE) for a location yesterday. With a firmware upgrade, they both were capable and set to use WPA pre-shared keys using TKIP for wireless encryption. The firmware upgrade enabled the communications between both the WRT54GS and the WRE54G to be WPA encrypted as well as communications between the clients connecting to either the AP or the RE.
After basic configuration and lock down of the AP and RE, I spent some time bouncing between channels to get the best wireless performance and signal. Oh, and not to mention, removing/disconnecting a cordless phone that shared the same frequency range. Luckily, the users at the site had only one cordless phone that was causing an issue.
The site had a mixture of wireless NICs both PCI and PCMCIA based cards. The PCI cards still suffer from range issues when installed in computers that are located/placed under a desk. That should be expected since the antenna and card are being placed in a location obstructing the wireless signal. Normally a user can move the PC around a little to get a good signal. I have not tried using an antenna that can be connected to the PCI card and placed on a desk; however, that may be a solution in future installs. For this install, I added a couple of Linksys WMP54GS cards to the desktops.
One other item to mention is that I had to place the RE in a location that was on the borderline wireless range of the main AP. I was pleased when the RE connected with the AP with no issues. The wireless performance for Internet bound requests from the computers that were connecting to the RE appeared to be fine even with the distance between the RE and AP.