Policy-Based VLANs

Rather than making VLAN membership decisions simply based on port configuration, each incoming frame can be examined by the classification engine which uses a match-based logic to assign the frame to a desired VLAN. For example, you could set up a policy which designates all e-mail traffic between the management officers of a company to a specific VLAN so that this traffic is restricted to certain portions of the network. With respect to network usage, the administrative advantages of policy classification would be application provisioning, acceptable use policy, and distribution layer policy. All of these provisions may involve simultaneous utilization of inter-switch links by multiple VLANs, requiring particular attention to tagged, forbidden, and untagged egress settings.

As described above, PVID determines the VLAN to which all untagged frames received on associated ports will be classified. Policy classification to a VLAN takes precedence over PVID assignment if:

• policy classification is configured to a VLAN, and
• PVID override has been enabled for a policy profile, and assigned to port(s) associated with the PVID.

For more information, refer to the Policy Classification chapter.