D-Link DIR-655 Wireless problems

Okey, so here's the deal.

I have a 16.000kbps ADSL2+ broadband,
and a D-Link DIR-655 Wireless Router connected to it.

Currently I have a laptop, a stationary computer, and my xbox 360 connected
to it. All wireless.

Everything is fine when I have only one connected at a time,
but when I connect my stationary and my xbox 360 at the same time, it seems
like I get a crash somewhere now and then, and I cant figure out what it is.

When I logon COD4 to play, I get 'connection interrupted' every.. ~15-30min,
wich causes me to go offline.

When I download anything on my stationary, it seems like the internet
connection 'goes down', or 'hangs' for ~20secs.
That would be the same problem on both systems (x360 and PC).

I have tried to lock an IP to their MAC-Adresses, so an IP-Conflict could
not be possible.

I have UPNP enabled, and all ports etc.
Still this is happening.

Anyone got any ideas?
Would be appriciated alot

1 Do you have the latest Firmware for your Router?
2 The latest Network Adaptor Drivers?
3 Try unbinding(untick) TCP/IPv6 in Network Connections, as it can cause
probs with some ISPs.
--

I'm using the same router. It is very fast and stable. I did have to upgrade
the firmware to version 1.11 before it worked properly. I was having similar
problems to yours.

Aye, I've upgraded the firmware a few times.
The newest atm is like 1.11eu2 or whatev, wich came out in 2008.
However, when I upgrade to it (it does say 1.11EU on 192.168.0.1),
it says that the firmware is from 2007.
Might just be that they didnt update the date inside the firmware tho.

And yes, I got the newest drivers for my wireless.
Tried the IPv6 trick as well, didnt do the trick :\

Hi Dag. I'm using one of this router's predecessors, but encountered
issues similar to yours. What worked for me was to assign a static IP
to the 360, then add that IP to the router's DMZ zone.

The following website has a great trouble-shooting guide for getting
XBox Live up and running on a wireless network, including info on
configuring the DMZ (albeit on a different vendor's router):