14-34
Port-Based Virtual LANs (VLANs) and GVRP
GVRP
Port-Based Virtual LANs
(VLANs) and GVRP
Table 14-2. Options for Handling “Unknown VLAN” Advertisements:
The CLI show gvrp command and the menu interface VLAN Support screen
show a switch’s current GVRP configuration, including the Unknown VLAN
settings.
Figure 14-22. Example of GVRP Unknown VLAN Settings
Unknown VLAN
Mode
Operation
Learn
(the Default)
Enables the port to dynamically join any VLAN for which it receives an
advertisement, and allows the port to adverti se other other VLANs it knows.
Block Prevents the port from dynamical ly joining a VLAN that is not statically
configured on that port. The port will st ill forward advertisements that were
received by the switch on other ports. Block should typic ally be used on
ports in unsecure networks, where there is exp osure to “attacks”, such as
ports where intruders can connect.
Disable Causes the port to ignore and drop all GVRP advertisements it receives and
also prevents the port from sending any GVRP advertisements.
GVRP Enabled
(Required for Unknown
VLAN operation.)
Unknown VLAN Settings
Default: Learn