Port-Based Virtual LANs (VLANs) and GVRP

GVRP

For example, in the following figure, Tagged VLAN ports on switch “A” and switch “C” advertise VLANs 22 and 33 to ports on other GVRP-enabled switches that can dynamically join the VLANs.

Switch “A”

 

 

 

 

Switch “C”

 

 

GVRP On

1

5

 

GVRP On

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Tagged

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11

VLAN 22

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Tagged

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VLAN 33

 

 

12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Switch “B”

 

 

 

Switch “D”

(No GVRP)

 

 

 

GVRP On

Tagged

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VLAN 22

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

Switch “D”:

Port 3 dynamically joins VLANs 22 and 33.

Port 6 dynamically joins VLAN 22 and 33.

Switch “C”:

Port 5 dynamically joins VLAN 22.

Ports 11 and 12 belong to Tagged VLAN 33.

2Switch “E” GVRP On

7

Switch “E”:

Port 2 dynamically joins VLANs 22 and 33. Port 7 dynamically joins VLANs 33 and 22.

 

Figure 11-25. Example of GVRP Operation

 

 

N o t e

A port can learn of a dynamic VLAN through devices that are not aware of

 

GVRP (Switch “B”, above). VLANs must be disabled in GVRP-unaware devices

 

to allow tagged packets to pass through.

 

A GVRP-aware port receiving advertisements has these options:

 

 

If there is not already a static VLAN with the advertised VID on the

 

receiving port, then dynamically create the VLAN and become a member.

 

If the switch already has a static VLAN assignment with the same VID as

 

in the advertisement, and the port is configured to Auto for that VLAN,

 

then the port will dynamically join the VLAN and begin moving that

 

VLAN’s traffic. (For more detail on Auto, see “Per-Port Options for

 

Dynamic VLAN Advertising and Joining” on page 11-39.)

 

Ignore the advertisement for that VID.

 

Don’t participate in that VLAN.

11-36