Just tracked this down. Kernel 2.6.26.3/5 wireless connections drops data.
Using a ethernet wireless bridge,
connects ok in adhoc mode. Pinging the other end of the link just stops gettting responses after a while. Reset the link, using ifdown/up at the laptop starts everthing working again.
Thought it was the ethernet wireless bridge. Original boot was with 2.6.26.5-45 -> no go. Backtracked to kernel 2.6.26.3-29 -> no go. Backtracked to 2.6.25-14 -> works. Appears to the the 4965 driver.
On the 2.6.26 kernels, sometimes the ping returns nothing initially then starts getting responses, then after about 10-20 pings stops getting a response. After that nothing except a restart (wireless only) gets it going again. On the 2.6.25 kernels no problems at all.
Anyone with similar problems? I am running a x86_64 Fedora 9 system. Updated regularly. Latest firmware is installed.