Configuration Guide MAC Address Configuration
The capacity of the address table for all linecards in the switch is allocated on
demand: If two users exchange the packets on the same line card, only the
MAC address space of the line card 1 is occupied.
High System Performance: Small system expenditure since the internal system
adopts the dispersive MAC address learning mode.
The disadvantages of the uniform MAC address learning: since the address
tables for all line cards in the switch are asynchronous, the packets are sent in
the unicast form for Line Card 1 while in the broadcast form for Line Card 2.
Figure-10 Uniform MAC address Learning: Unicast and Multicast Packets Forward
When the UserC under the Line Card 2 sends a packet to the UserA, since the
Line Card 2 has learned the MAC address for the UserA, the packet will be
forwarded to the UserA in the unicast form.
When the UserC under the Line Card 2 sends a packet to the UserB, since the
Line Card 2 has learned the MAC address for the UserB, the packet will be
forwarded in the broadcast form. At this time, the UserD that is in the same
VLAN of UserC also receives the packet. The packet will be forwarded in the
unicast form to the UserB after being sent to the Line Card 1.
B. MAC Address Synchronization
In the uniform MAC address learning mode, the Ethernet switch supports the
MAC address synchronization function. All line cards in the switch no longer
learn the MAC address in the dispersive MAC address learning mode and
synchronize the new MAC address learned by any line card.
The advantages of the MAC address synchronization: the MAC addresses
within the switch are synchronous. It helps prevent the packets in the network
from being forwarded in the broadcast form if the number of users connecting
to the switch exceeds the MAC address table limit.
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