Port-Based Virtual LANs (VLANs) and GVRP

GVRP

Note also that a port belonging to a Tagged or Untagged static VLAN has these configurable options:

Send VLAN advertisements, and also receive advertisements for VLANs on other ports and dynamically join those VLANs.

Send VLAN advertisements, but ignore advertisements received from other ports.

Avoid GVRP participation by not sending advertisements and dropping any advertisements received from other devices.

IP Addressing. A dynamic VLAN does not have an IP address, and moves traffic on the basis of port membership in VLANs. However, after GVRP creates a dynamic VLAN, you can convert it to a static VLAN. Note that it is then necessary to assign ports to the VLAN in the same way that you would for a static VLAN that you created manually. In the static state you can configure IP addressing on the VLAN and access it in the same way that you would any other static (manually created) VLAN.

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. For example, suppose that in figure 11-25 (page 11-36), 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”.

When you enable GVRP on a switch, you have the per-port join-request options listed in table 11-3:

11-37