Automatic Vlan Registration; Garp; Garp Timers; Gvrp - ZyXEL Communications ZyXEL Dimension GS-4012F User Manual

GS-4012F/4024 User's Guide
The egress (outgoing) port(s) of a frame is determined on the combination of the destination
MAC address and the VID of the frame. For a unicast frame, the egress port (based on the
destination MAC address) must be a member of the VID, also; otherwise, the frame is
blocked. A broadcast frame (or a multicast frame for a multicast group that is known by the
system) is duplicated only on ports that are members of the VID (except the ingress port
itself), thus confining the broadcast to a specific domain.
Whether to tag an outgoing frame depends on the setting of the egress port on an individual
VLAN and port basis (remember that a port can belong to multiple VLANs). If the tagging on
the egress port is enabled for the VID of a frame, then the frame is transmitted as a tagged
frame; otherwise, it is transmitted as an untagged frame.

8.2 Automatic VLAN Registration

GARP and GVRP are the protocols used to automatically register VLAN membership across
switches.

8.2.1 GARP

GARP (Generic Attribute Registration Protocol) allows network switches to register and de-
register attribute values with other GARP participants within a bridged LAN. GARP is a
protocol that provides a generic mechanism for protocols that serve a more specific
application, for example, GVRP.

8.2.1.1 GARP Timers

Switches join VLANs by making a declaration. A declaration is made by issuing a Join
message using GARP. Declarations are withdrawn by issuing a Leave message. A Leave All
message terminates all registrations. GARP timers set declaration timeout values.

8.2.2 GVRP

GVRP (GARP VLAN Registration Protocol) is a registration protocol that defines a way for
switches to register necessary VLAN members on ports across the network. Enable this
function to permit VLANs groups beyond the local switch.
Please refer to the following table for common IEEE 802.1Q VLAN terminology.

Table 13 IEEE 802.1Q VLAN Terminology

VLAN PARAMETER TERM
VLAN Type
84
DESCRIPTION
Permanent VLAN This is a static VLAN created manually.
Dynamic VLAN This is a VLAN configured by a GVRP registration/
deregistration process.
Chapter 8 VLAN