Per-port options for handling GVRP "unknown VLANs"

An "unknown VLAN" is a VLAN that the switch learns of by receiving an advertisement for that VLAN on a port that is not already a member of that VLAN. If the port is configured to learn unknown VLANs, then the VLAN is dynamically created and the port becomes a tagged member of the VLAN.

GVRP unknown VLAN settings

Suppose that in the Example of GVRP operation, port 1 on switch A is connected to port 5 on switch C. Because switch A has VLAN 22 statically configured, while switch C does not have this VLAN statically configured (and does not "Forbid" VLAN 22 on port 5), VLAN 22 is handled as an "Unknown VLAN" on port 5 in switch C. Conversely, if VLAN 22 was statically configured on switch C, but port 5 was not a member, port 5 would become a member when advertisements for VLAN 22 were received from switch A.

The CLI show gvrp command and the menu interface VLAN Support screen show a switch's current GVRP configuration, including the Unknown VLAN settings.