AT-S79 Management Software User’s Guide
For example, if you had a port-based VLAN titled Marketing that spanned three AT-GS950 Series switches, you would assign the Marketing VLAN on each switch the same VID.
You can assign this number manually or allow the AT-S79 management software to do it automatically. If you allow the management software to do it automatically, it selects the next available VID. This is acceptable when you are creating a new, unique VLAN.
If you are creating a VLAN on a switch that will be part of a larger VLAN that spans several switch, you must assign the number yourself so that the VLAN has the same VID on all switches.
You need to specify which ports on the switch are to be members of a port- based VLAN. Ports in a port-based VLAN are referred to as untagged ports and the frames received on the ports as untagged frames. The names derive from the fact that the frames received on a port will not contain any information that indicates VLAN membership, and that VLAN membership will be determined solely by the port’s PVID. (There is another type of VLAN where VLAN membership is determined by information within the frames themselves, rather than by a port’s PVID. This type of VLAN is explained in “Tagged VLAN Overview” on page 80.)
A port on a switch can be an untagged member of only one port-based VLAN at a time. An untagged port cannot be assigned to two port-based VLANs simultaneously.
Each port in a port-based VLAN must have a port VLAN identifier (PVID). The switch associates a frame to a port-based VLAN by the PVID assigned to the port on which the frame is received, and forwards the frame only to those ports with the same PVID. Consequently, all ports of a port-based VLAN must have the same PVID. Additionally, the PVID of the ports in a VLAN must match the VLAN’s VID.
For example, if you were creating a port-based VLAN on a switch and you had assigned the VLAN the VID 5, the PVID for each port in the VLAN would need to be assigned the value 5.
Some switches assign the PVID value automatically when you assign an untagged port to a VLAN. However, with the AT-S79 management software you must perform this task manually.
Below are the guidelines to creating a port-based VLAN.
Each port-based VLAN must be assigned a unique VID. If a particular VLAN spans multiples switches, each part of the VLAN on the different switches should be assigned the same VID.
A port can be an untagged member of only one port-based VLAN at a time.
