ZyXEL Communications XGS2220 Series User Manual page 600

Figure 446 VLAN Forwarding Frame
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.
79.32.2.1 Automatic VLAN Registration
GARP and GVRP are the protocols used to automatically register VLAN membership across switches.
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.
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 Declarations are withdrawn by issuing a Leave message.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.
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 VLAN
groups beyond the local Switch.
Please refer to the following table for common IEEE 802.1Q VLAN terminology.
Table 348 IEEE 802.1Q VLAN Terminology
VLAN PARAMETER
VLAN Type
VLAN Administrative
Control
Chapter 79 Networked AV Mode
TERM DESCRIPTION
Permanent VLAN This is a static VLAN created manually.
Dynamic VLAN This is a VLAN configured by a GVRP registration or de-registration
process.
Registration Fixed Fixed registration ports are permanent VLAN members.
Registration Ports with registration forbidden are forbidden to join the specified
Forbidden VLAN.
Normal Registration Ports dynamically join a VLAN using GVRP.
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