HP Network Direr Software Products manual 3Com Network Director Vlan Concepts

508CHAPTER 13: VLAN MANAGEMENT

Figure 262 VLANs Connected Using an 802.1Q Tagged Link Between Switches

3Com Network

Director VLAN

Concepts

To avoid any VLAN subdivision, it is recommended that all inter-switch connections are made members of all available VLANs to ensure connectivity at all times. For example, the connections between Switches A and B, and between Switches A and C should be 802.1Q tagged and carrying VLANs 1 and 2 to ensure connectivity.

Discovering VLANs in 3Com Network Director

When you perform a network discovery 3Com Network Director will retrieve the following information from each supported switch:

■the textual description of the VLAN

■the 802.1Q VLAN ID

■the ports on the device that are tagged members of the VLAN

■the ports on the device that are untagged members of the VLAN

■any Layer 3 information associated with the VLAN e.g. IP address and subnet mask, or protocol type if a non-IP VLAN.

In addition to gathering VLAN information from switches, 3Com Network Director will also infer the VLAN membership of devices that have no VLANs configured.