Download SMC (SMC6924MTNMM) Network Management Device
Transcript
ADVANCED TOPICS Port-based VLANs are tied to specific ports. The switch’s forwarding decision is based on the destination MAC address and its associated port. Therefore, to make valid forwarding and flooding decisions, the switch learns the relationship of the MAC address to its related port—and thus to the VLAN—at run-time. When the switch receives a frame, it assigns the frame to the port’s default VLAN if the frame is untagged (determined by the PVID of the receiving port), or maps it for output to the broadcast domain associated with the frame’s VLAN tag. Port Overlapping Port overlapping can be used to allow access to commonly shared network resources among different VLAN groups, such as file servers or printers. Note that if you implement VLANs which do not overlap, but still need to communicate, you can connect them using a Layer 3 switch or a router. Automatic VLAN Registration (GVRP) GVRP defines a system whereby the switch can automatically learn the VLANs each endstation should be assigned to. If an endstation (or its network adapter) supports the IEEE 802.1Q VLAN protocol, it can be configured to broadcast a message to your network indicating the VLAN groups it wants to join. When this switch receives these messages, it will automatically place the receiving port in the specified VLANs, and then forward the message to all other ports. When the message arrives at another switch that supports GVRP, it will also place the receiving port in the specified VLANs, and pass the message on to all other ports. VLAN requirements are propagated in this way throughout the network. This allows GVRP-compliant devices to be automatically configured for VLAN groups based solely on endstation requests. 4-5