Amer Networks SS2R48G4i V2 - Manual (Page 90)

SS2R24G4i/SS2R48G4i
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added to the MAC table.
4. Now the MAC table has two dynamic entries, MAC address 00-01-11-11-11-11 - port 5 and
00-01-33-33-33-33 -port 12.
5. After the communication between PC1 and PC3, the switch does not receive any message sent
from PC1 and PC3. And the MAC address mapping entries in the MAC table are deleted after 300
seconds. The 300 seconds here is the default aging time for MAC address entry in SS2R24/48G4i
switch. Aging time can be modified in the switch.
8.1.2 Forward or Filte
The switch will forward or filter received data frames according to the MAC table. Take the above
figure as an example, assuming DCN switch have 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 DCN
switch will be
MAC Address Port number Entry added by
00-01-11-11-11-11 5 Dynamic learning
00-01-22-22-22-22 5 Static configuration
00-01-33-33-33-33 12 Dynamic learning
00-01-44-44-44-44 12 Static configuration
z Forward data according to the MAC table
If PC1 sends a message to PC3, the switch will forward the data received on port 5 from port 12.
z 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
z Broadcast frame
z Multicast frame
z 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 frames 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 ports; when the destination
MAC address in a unicast frame is not found in the MAC table, the switch will broadcast the unicast