Enterasys Networks 2H258, 2E253, 2H253 Known Unicasts, Vlan Configuration, Managing the Switch

VLAN Configuration

12.7.2.2 Known Unicasts

When a VLAN switch receives a frame with a known MAC address as its destination address, the action taken by the switch to determine how the frame is transmitted depends on the VLAN, the VLAN associated FDB ID, and if the port identified to send the frame is enabled to do so.

When a frame is received it is classified into a VLAN. The destination address is looked up in the FDB ID associated with the VLAN. If a match is found, it is forwarded out the port identified in the lookup if, and only if, that port is allowed to transmit frames for that VLAN. If a match is not found, then the frame is flooded out all ports that are allowed to transmit frames belonging to that VLAN.

For example, assume that a frame is received by the switch depicted back in Figure 12-2. This frame is a unicast untagged frame received on Port 3. The frame is then classified for VLAN C. The switch then makes its forwarding decision by comparing the destination MAC address to its filtering database. In this case, the MAC address is looked up in the filtering database FDB ID 3, which is associated with VLAN C and VLAN D. The switch recognizes the destination MAC address of the frame as being located out Port 4.

Having made the forwarding decision, the switch now examines the Port VLAN List of Port 4 to determine if it may transmit a frame belonging to VLAN C. If so, the frame is transmitted out Port

4.If Port 4 has not been configured to transmit frames belonging to VLAN C, the frame is discarded.

12.8 VLAN CONFIGURATION

This section describes how to set up the switch for local or remote management, and the VLAN Local Management screens used to create and configure VLANs in a SmartSwitch.

12.8.1 Managing the Switch

The switch may be managed locally via a terminal connected to the COM port, or remotely (SNMP or Telnet sessions) from a management station connected to a switch port that is a member of the same VLAN as the switch’s Host Data Port. (By default, this is the default VLAN.) When the switch is configured with VLANs, special precautions must be taken to use remote management.

VLAN Operation and Network Applications 12-11