Configuring VLANs 191

VLAN Names

To create a VLAN, you must assign a name to it. VLAN names must be globally unique across a Mobility Domain to ensure the intended user connectivity as determined through authentication and authorization.

Every VLAN on a WX has a VLAN name, used for authorization purposes, and a VLAN number. VLAN numbers can vary uniquely for each WX and are not related to 802.1Q tag values even when used.

You cannot use a number as the first character in a VLAN name.

Roaming and VLANs

WX switches in a Mobility Domain contain a user’s traffic within the VLAN the user is assigned to. For example, if you assign a user to VLAN red, the WX switches in the Mobility Domain contain the user’s traffic within VLAN red configured on the WX switches.

The WX switch through which a user is authenticated must be a member of the Mobility Domain the user is assigned to. However, you are not required to configure the VLAN on all WX switches in the Mobility Domain. When a user roams to a WX switch that is not a member of the VLAN the user is assigned to, the WX switch can tunnel traffic for the user through another WX switch that is a member of the VLAN. (For more information about Mobility Domains, see “Defining a Mobility Domain” on page 90.)

Because the default VLAN might not be in the same subnet on each WX switch, 3Com recommends that you do not rename the default VLAN or use it for user traffic. Instead, configure other VLANs for user traffic.

Traffic Forwarding A WX switches traffic at Layer 2 among ports in the same VLAN. For example, suppose you configure ports 4 and 5 to belong to VLAN 2 and ports 6 and 7 to belong to VLAN 3. As a result, traffic between port 4 and port 5 is switched, but traffic between port 4 and 6 needs to be routed by an external router.

802.1Q Tagging The tagging capabilities of the WX are flexible. You can assign 802.1Q tag values on a per-VLAN, per-port basis. The same VLAN can have different tag values on different ports. In addition, the same tag value can be used by different VLANs but on different network ports.

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HP Manager Software manual Vlan Names, Roaming and VLANs