Controlling how individual ports handle advertisements for new VLANs (CLI)

When GVRP is enabled on the switch, use the unknown-vlans command to change the Unknown VLAN field for one or more ports.

Syntax: 


interface <port-list> unknown-vlans [learn | block | disable]

Changes the Unknown VLAN field to control how one or more ports handle advertisements. Use at either the Manager or interface context level for a port.

Changing the Unknown VLANs field

In the following example, the first command changes the configuration to Block, the second command displays the new configuration: 

switch(config)# interface 1-2 unknown-vlans block

Switch(config)# show gvrp
 GVRP support
  Maximum VLANs to support [256] : 256
  Primary VLAN : DEFAULT_VLAN 
  GVRP Enabled [No] : Yes

  Port Type      | Unknown VLAN Join  Leave Leaveall
  ---- --------- + ------------ ----- ----- --------
  1    10/100TX  | Block        20    300   1000
  2    10/100TX  | Block        20    300   1000
  3    10/100TX  | Learn        20    300   1000
  4    10/100TX  | Learn        20    300   1000

When you enable GVRP on a switch, you have the per-port join-request options listed in the following table:

Options for handling unknown VLAN advertisements

Unknown VLAN Mode

Operation

Learn

(the Default)

Enables the port to become a member of any unknown VLAN for which it receives an advertisement. Allows the port to advertise other VLANs that have at least one other port on the same switch as a member.

Block

Prevents the port from joining any new dynamic VLANs for which it receives an advertisement.Allows the port to advertise other VLANs that have at least one other port as a member.

Disable

Causes the port to ignore and drop all GVRP advertisements it receives and prevents the port from sending any GVRP advertisements.