By default, any PC or onward LAN segment connected to one of the Vigor’s four Ethernet switch sockets will be able to communicate with any other PC or device on any of the other three ports.
VLAN (Virtual LAN) is available on some Vigor routers and enables you to segment each of the Ethernet ports to create separate groups of users, so that they can or can’t communicate with users in other segments, as required.
Imagine two separate companies within the same building want to share the same broadband connection, but want to be secure from each other (so that they the two companies cannot access each of their LANs). To do this on the Vigor, you would create two VLAN groups. One contains exclusively P1 (Ethernet Port 1 on the back of the Vigor which will connect to Company A’s network) and the other VLAN group contains exclusively P2 (which will connect to Company B’s network). Both companies then have access to the Internet, but not to each other.
Take the same scenario as above, but this time there is a local server which both companies want access to, but still, not to have access to each other. We can connect the common/shared server to port P3 this time, and include P3 in both VLAN Group 1 (which will also include Company A) and to VLAN Group 2 (which will also include Company B).
The VLAN facility allows up to four VLAN groups to be defined which can include or exclude any combination of the router’s four Ethernet port (P1/P2/P3/P4).