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for MAC address entry in ES4626/ES4650. Aging time can be modified in
ES4626/ES4650.
4.1.2 Forward or Filter
The switch will forward or filter received data frames according to the MAC table.
Take the above figure as an example, assuming ES4626/ES4650 has learnt the MAC
address of PC1 and PC3, and the user manually configured the mapping relationship for
PC2 and PC4 to ports. The MAC table of ES4626/ES4650 will be:
MAC Address Port number Entry added by
00-01-11-11-11-11 1/5 Dynamic learning
00-01-22-22-22-22 1/5 Static configuration
00-01-33-33-33-33 1/12 Dynamic learning
00-01-44-44-44-44 1/12 Static configuration
1. Forward data according to the MAC table
If PC1 sends a message to PC3, the switch will forward the data received on port 1/5 from
port 1/12.
2. Filter data according to the MAC table
If PC1 sends a message to PC2, the switch, on checking the MAC table, will find PC2 and
PC1 are in the same physical segment and filter the message (i.e. drop this message).
Three types of frames can be forwarded by the switch:
Broadcast frame
Multicast frame
Unicast frame
The following describes how the switch deals with all the three types of frames:
1. Broadcast frame: The switch can segregate collision domains but not broadcast
domains. If no VLAN is set, all devices connected to the switch are in the same
broadcast domain. When the switch receives a broadcast frame, it forwards the frame
in all ports. When VLANs are configured in the switch, the MAC table will be adapted
accordingly to add VLAN information. In this case, the switch will not forward the
received broadcast frames in all ports, but forward the frames in all ports in the same
VLAN.
2. Multicast frame: When IGMP Snooping function is not enabled, multicast frames are
processed in the same way as broadcast frames; when IGMP Snooping is enabled,
the switch will only forward the multicast frame to the ports belonging to the very
multicast group.
3. Unicast frame: When no VLAN is configured, if the destination MAC addresses are in
the switch MAC table, the switch will directly forward the frames to the associated