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based on the Filtering Database. If you want to allow tagged frames to be forwarded to a certain port, this port must be the egress port of this VID. The egress port is an outgoing port for the specified VLAN, that is, frames with a specified VID tag can go through this port. Filtering Database stores and organizes VLAN registration information useful for switching frames to and from switch ports. It consists of static registration entries (Static VLAN or SVLAN table) and dynamic registration entries (Dynamic VLAN or DVLAN table). SVLAN table is manually added and maintained by the administrator.
DVLAN table is automatically learned via GVRP protocol, and can't be created or updated by the administrator.
VLAN entries in Filtering Database have the following information:
1.VID: VLAN ID
2.Port: The switch port number
3.Ad Control: Registration administration control. There are 3 types of ad control, including forbidden registration, fixed registration and normal registration.
z Forbidden registration: This port is forbidden to be the egress port of the specified VID.
z Fixed registration: While ad control is fixed registration, it means this is a static registration entry. This port is the egress port of the specified VID (a member port of the specified VLAN). Frames with the specified VID tag can go through this port.
z Normal registration: While ad control is normal registration, it means this is a dynamic registration entry. The forwarding decision is depended on the Dynamic VLAN table.
4.Egress tag Control: This information is used for Egress Process. The value
may be tagged or untagged. If the value is tagged, outgoing frames on the egress port is tagged. If the value is untagged, the tag will be removed before a frame leaves the egress port.
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