The local network is a virtual domain, broadcast separate network switch.

every Switch by default, a domain is broadcast, but to prevent a storm of broadcast packets or reducing broadcast packets on Layer 2, you can create a local area network Virtual, a switch to two-or multi-domain plays a distinct breakdown.

the two computers to a switch are connected, if every A in a local area network virtual be different to be able to communicate at Layer 2 will not be.