VDE is an ethernet compliant virtual network which includes tools such
as 'vde_switch' and 'vdeqemu'. VDE switch has several virtual ports
where virtual machines, applications, virtual interfaces and
connectivity tools can be virtually plugged in. VDE qemu works as a
wrapper for running qemu virtual machines that connects transparently
to a specified vde_switch

VDE is dependant upon TUN/TAP support in the Linux Kernel; this comes
enabled by default with Slackware 13's 'generic' kernel.  To enable
TUN/TAP support manually, you must set the following entry in your 
kernel's '.config' file and recompile:
	CONFIG_TUN=m

##  Experimental features
If you know/want vde2's experimental features, execute the script as:
EXPERIMENTAL=true sh vde2.SlackBuild

## Configuration
An init script has been provided in /etc/rc.d/rc.vde2 to use with 
vde_switch. Edit this script and provide the TAP inteface name as 
well as the subnet for your Virtual Switch to use.  Do NOT choose
a subnet which is already in use. More than likely, the default 
values will work fine.

## VDE + Qemu/kvm
A common usage for vde_switch is to be able to have emulated OS's 
via Qemu behave as if they were actually attached to a Local Network.
To enable this functionality with Qemu, replace any calls to 'qemu'
with the following command:

vdeqemu -net vde,vlan=0 -net nic,vlan=0,macaddr=AA:BB:CC:DD:EE:FF

Note that the 'macaddr' string is optional but can prove to be
quite useful when used in conjuction with a DHCP server (such as
dhcpd or dnsmasq) to assign IP's based upon MAC address.

Do not forget to include the options which point vdeqemu to your
ISO image to boot along with any other options you may have used
with 'qemu' such as -localtime, -nographic etc.

## Startup
To have this start upon each boot, add the following lines to
/etc/rc.d/rc.local and make sure rc.vde2 is executable.

	# Start vde_switch
	if [ -x /etc/rc.d/rc.vde2 ]; then
	   /etc/rc.d/rc.vde2 start
	fi

## For more information you can check:
http://wiki.virtualsquare.org
http://alien.slackbook.org/dokuwiki/doku.php?id=slackware:vde&s=qemu