IronPort Systems 4108GL User Manual

Page 338

14-32

Port-Based Virtual LANs (VLANs) and GVRP
GVRP

-Ba

sed V

tual

LANs

(VLAN

s) a

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.

Figure 14-21. 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 14-35.)

■

Ignore the advertisement for that VID.

■

Don’t participate in that VLAN.

Switch “A”
GVRP On

Switch “B”
(No GVRP)

Switch “C”
GVRP On

Switch “D”
GVRP On

Tagged
VLAN 22

Switch “E”
GVRP On

Tagged
VLAN 33

Switch “C”:
Port 5 dynamically joins VLAN 22.
Ports 11 and 12 belong to Tagged VLAN 33.

Switch “E”:
Port 2 dynamically joins VLANs 22 and 33.
Port 7 dynamically joins VLANs 33 and 22.

Switch “D”:
Port 3 dynamically joins VLANs 22 and 33.
Port 6 dynamically joins VLAN 22 and 33.