VLAN Terms and Definitions lists terms and definitions used in VLAN configuration.
VLAN Terms and Definitions
| Term | Definition |
|---|---|
| Default VLAN | The VLAN to which all ports are assigned upon initialization. The default VLAN has a VLAN ID of 1 and cannot be deleted or renamed. |
| Filtering Database | A database structure within the switch that keeps track of the associations between MAC addresses, VLANs, and interface (port) numbers. The Filtering Database is referred to when a switch makes a forwarding decision on a frame. |
| Filtering Database Identifier (FID) | Addressing information that the device learns about a VLAN is stored in the filtering database assigned to that VLAN. Several VLANs can be assigned to the same FID to allow those VLANs to share addressing information. This enables the devices in the different VLANs to communicate with each other when the individual ports have been configured to allow communication to occur. The configuration is accomplished using the Local Management VLAN Forwarding Configuration screen. By default a VLAN is assigned to the FID that matches its VLAN ID. |
| Forwarding List | A list of the ports on a particular device that are eligible to transmit frames for a selected VLAN. |
| GARP Multicast Registration Protocol (GMRP) | A GARP application that functions in a similar fashion as GVRP, except that GMRP registers multicast addresses on ports to control the flooding of multicast frames. |
| GARP VLAN Registration Protocol (GVRP) | A GARP application used to dynamically create VLANs across a switched network. |
| Generic Attribute Registration Protocol (GARP) | GARP is a protocol used to propagate state information throughout a switched network. |
| Multiple VLAN Registration Protocol (MVRP) | An MRP application used to dynamically create VLANs across a switched network. |
| Multiple Registration Protocol (MRP) | MRP is a protocol used to propagate state information throughout a switched network. |
| Port VLAN List | A per port list of all eligible VLANs whose frames can be forwarded out one specific port and the frame format (tagged or untagged) of transmissions for that port. The Port VLAN List specifies what VLANs are associated with a single port for frame transmission purposes. |
| Tag Header (VLAN Tag) | Four bytes of data inserted in a frame that identifies the VLAN/frame classification. The Tag Header is inserted into the frame directly after the Source MAC address field. Twelve bits of the Tag Header represent the VLAN ID. The remaining bits are other control information. |
| Tagged Frame | A data frame that contains a Tag Header. A VLAN aware device can add the Tag Header to any frame it transmits. |
| Untagged Frame | A data frame that does not have a Tag Header. |
| VLAN ID | A unique number (between 1 and 4094) that identifies a particular VLAN. |
| VLAN Name | A 32-character alphanumeric name associated with a VLAN ID. The VLAN Name is intended to make user-defined VLANs easier to identify and remember. |
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