Improving network performance on RasPi / Edimax EW-7811Un

If you're having intermittent network issues with a Raspberry Pi, such as intermittent reachability or delays mid-session on SSH, try the following

Make a file 8192cu.conf in directory /etc/modprobe.d/ with the command

sudo nano /etc/modprobe.d/8192cu.conf

and add the following lines

# Disable power management
options 8192cu rtw_power_mgnt=0 rtw_enusbss=0

(From https://www.raspberrypi.org/forums/viewtopic.php?t=61665)