To make the PVRST+ module completely operational, you must configure the VLAN module. A VLAN is a network of computers that behave as if they are connected to the same wire even though they are physically located on different segments of a LAN. VLANs are configured through software rather than hardware, which make them extremely flexible. One of the biggest advantages of VLANs is that when a computer is physically moved to another location, the computer can stay on the same VLAN without any hardware reconfiguration.
For VLAN information to be passed between switches, trunking must be configured between the switches. VLAN trunking allows a port to pass traffic from multiple VLANs between the two switches. Frames traveling over a trunk are tagged to identify to which VLAN the frames belong. When implementing trunking between switches, the ports at either end of the connection is set up for trunk mode and the trunk encapsulation mode must match.
To configure the VLAN module when the spanning tree mode is set to PVRST+, you must:
Disable the GVRP module.
Create all VLANs on each switch in the network, as dynamic VLAN learning (GVRP) is not supported.
Configure the ports as a trunk or access port.
Restart PVRST+ in the case of multiple instances of VLANs after you have mapped the ports to any context in MST mode.
These configuration guidelines must be met:
A port that is an untagged member of a VLAN cannot be configured as a trunk port.
An access port must become a member of the VLAN that is configured as PVID.
Port membership is not allowed in the PVRST+ software. The port becomes a member of a VLAN only after you configure the port as a trunk or access port.
Because explicit VLAN member port configurations are not encouraged in PVRST+ mode, you should explicitly configured ports as access or trunk to ensure that they are assigned to different VLANs.
The port configured as trunk automatically becomes a member port for all VLANs created on the switch.