Manual

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Москва, Новозаводская ул., 18, стр. 1
163
If PC1 sends a message to PC3, the switch will forward the data received on port 1/5 from
port1/12.
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: For the unknown multicast, the switch will broadcast it in the same vlan,
but the switch only forwards the multicast frames to the multicast group’s port if IGMP
Snooping function or the static multicast group has been configured.
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 ports; when
the destination MAC address in a unicast frame is not found in the MAC table, the switch
will broadcast the unicast frame. When VLANs are configured, the switch will forward
unicast frame within the same VLAN. If the destination MAC address is found in the MAC
table but belonging to different VLANs, the switch can only broadcast the unicast frame in
the VLAN it belongs to.
19.2 Mac Address Table Configuration Task List
1. Configure the MAC address aging-time
2. Configure static MAC forwarding or filter entry
3. Clear dynamic address table
4. Configure MAC learning through CPU control
1. Configure the MAC aging-time
Command
Explanation
Global Mode