Specifications

Chapter 1 Introduction Installation and Operation Manual
1-10 Functional Description LA-210 Ver. 1.5
Forwarding Process
The forwarding process is performed based on the frame destination MAC VID
pair. The frame is forwarded to the bridge port that was specified in the MAC
table for this MAC VID pair entry.
Untagged frames are forwarded according to the PVID that was attached to that
frame during the ingress process.
Frames are forwarded, dropped, or flooded according to the following guidelines:
• Forwarded: If the bridge port of the pair entry (DA, VID) in the MAC table is
both an active bridge port and a member of the VLAN, the frame is forwarded
to that bridge port only.
• Dropped:
 If the bridge port for the pair entry (DA, VID) in the MAC table is the port
on which the frame was received, the frame is dropped.
 If there are no active ports associated with the frame’s VID, or if the VID
is not defined at all, the frame is dropped.
• Flooded:
 If the pair (DA, VID) is not learned and does not exist in the MAC table,
the frame is transmitted to all bridge ports that are associated with the
frame’s VLAN ID.
 Multicasts and broadcasts are flooded only through the bridge ports
whose VLAN ID is identical to the frame’s VLAN ID.
Transmission Process
After the forwarding process identifies the destination bridge port/ports to which
the frames must be transmitted, the frames are transmitted in the appropriate
format.
The frame format can be configured for each VLAN and port:
• VLAN-tagged: In this mode:
 VLAN-tagged frames are transmitted unchanged.
 Untagged frames are transmitted tagged with priority according to the
default priority of the ingress bridge port, and VID=PVID of the port from
which they entered.
 Priority-tagged frames are transmitted tagged with original priority and
VID = PVID.
• Untagged: In this mode, all frames are transmitted as untagged.