Layer 2 LAN Switching Services for Layer 3
Along with significant performance improvements, Layer 2 switching has also provided additional functions to enhance the deployment and performance of Layer 3 protocols. Three of these functions are Virtual LANs (VLANs), Layer 2 traffic prioritization, and Layer 3 switching. These functions, like port trunking and full-duplex port operation, are made possible by adding additional logic features to the switching logic's ASIC chip.
A switch that supports VLAN provides the capability to partition the switch's ports into artificial Layer 2 broadcast domains. A VLAN behaves exactly like a physical Layer 2 broadcast domain. Unicast, broadcast, and multicast traffic sent into the VLAN are only visible ...