HP Network Direr Software Products manual Communication between VLANs

504CHAPTER 13: VLAN MANAGEMENT

Figure 260 Example of VLANs Distributed Amongst More Than One Switch

The Default VLAN A new or initialized switch contains a single VLAN, the default VLAN. This VLAN has the following definition:

■VLAN Name — typically Default VLAN or just Default

■802.1Q VLAN ID — 1 (if tagging required)

All ports on the switch are initially placed in this VLAN, untagged.

Communication between VLANs

Communication between two different VLANs can only take place if they are connected to an appropriately configured router or a Layer 3 switch. Alternatively, if the switch containing the VLANs is itself a Layer 3 switch and is configured correctly, it will be able to route the traffic from one VLAN to the other internally.

In an IP environment, communication between VLANs is achieved by defining VLAN-based IP interfaces on a Layer 3 switch or router. Commonly, each VLAN corresponds to one IP subnet, although it is possible to have more than one IP subnet per VLAN.

For example, a network has two VLANs: one VLAN with ID 2 defines devices on the subnet 192.168.50.0/255.255.255.0 and another VLAN with ID 3 defines devices on the subnet 192.168.51.0/255.255.255.0. For devices on one VLAN to communicate with devices on the other