I have been having problems with my DIR-655 router for months now.
When I got the router (Aug 2010) I set it up no sweat and it worked fine for about nine months with the out-of-the-box, default settings. This last summer I started losing connection on my PCs when on the web. The wireless would disappear for a few minutes every day. Annoying, but it happened so intermittently that I didn't bother to investigate further. (Note: I was never disconnected from XBOX LIVE during this period.) Then about two-three months ago, it got worse and I was dropping multiple times a day. I finally decided to do a complete reboot, refresh of the modem and router. Now it's even WORSE because I'm occasionally disconnected from XBOX LIVE and that never happened before.
Just last night I was watching a video on my XBOX 360 and I saw myself disconnected from XBOX LIVE. I went to my bedroom computer. There was no wireless signal. I went to my office computer, which is hardwired into the router (i.e., it doesn't run on WIFI) and its connection to the Internet was solid. This tells me the modem is fine and the ISP is fine. There is a flaw with the router. (I also temporarily switched out the DIR-655 with an old DI-634M and didn't experience drops with that router.)
Things I've tried: Numerous reboots of the router. ... Checking for new firmware. ... Disabling "auto channel scan" and manually setting channels. (After using "inSSIDer 2.0" to see what channels my neighbors were using.) ... Turning off QoS, the feature that is supposed to prioritize gaming traffic. ... Unchecking the "dynamic fragmentation" box, which I've read may produce undesired results. ... Setting up port forwarding for XBOX LIVE and DHCP reservations for my devices.
I stress that I never had to do anything special to get my router to work for the first nine months.
Can anyone suggest something to try? Or is my router a "lemon?"