Filter
Top Products
Chapter 9 VLAN
MGS3700-12C User’s Guide
118
9.1.1 Forwarding Tagged and Untagged Frames
Each port on the Switch is capable of passing tagged or untagged frames. To
forward a frame from an 802.1Q VLAN-aware switch to an 802.1Q VLAN-unaware
switch, the Switch first decides where to forward the frame and then strips off the
VLAN tag. To forward a frame from an 802.1Q VLAN-unaware switch to an 802.1Q
VLAN-aware switch, the Switch first decides where to forward the frame, and then
inserts a VLAN tag reflecting the ingress port's default VID. The default PVID is
VLAN 1 for all ports, but this can be changed.
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.
9.2 Automatic VLAN Registration
GARP and GVRP are the protocols used to automatically register VLAN
membership across switches.
9.2.1 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.
9.2.1.1 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 Declarations are withdrawn by issuing a Leave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.
9.2.2 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 VLAN groups beyond the local Switch.