Virtual LAN - Protocol-Based VLANs

Protocol-Based VLANs

In a switch that supports protocol-based VLANs, traffic is handled on the basis of its protocol. Essentially, this segregates or forwards traffic from a port depending on the particular protocol of that traffic; traffic of any other protocol is not forwarded on the port.

For example, it is possible to connect to a given switch the following:

• a host generating ARP traffic to port 10
• a network with IPX traffic to port 20
• a router forwarding IP traffic to port 30

If a protocol-based VLAN is created that supports IP and contains all three ports, this prevents IPX traffic from being forwarded to ports 10 and 30, and ARP traffic from being forwarded to ports 20 and 30, while still allowing IP traffic to be forwarded on all three ports.