H3C Technologies H3C WX3000 Series Unified Switches - Manual (Page 163)

21-2
Generally, the majority of MAC address entries are created and maintained through MAC address
learning. The following describes the MAC address learning process of the device:
1) As shown in Figure 21-1 , User A and User B are both in VLAN 1. When User A communicates with
User B, the packet from User A needs to be transmitted to GigabitEthernet 1/0/1. At this time, the
device records the source MAC address of the packet, that is, the address “MAC-A” of User A to
the MAC address table of the switch, forming an entry shown in
Figure 21-2 .
Figure 21-1 MAC address learning diagram (1)
Geth 1/0/1
Geth 1/0/3 Geth 1/0/4
User B
User A
User C
Figure 21-2 MAC address table entry of the switch (1)
Port VLAN ID MAC-address
GigabitEthernet1/0/1 1 MAC-A
2) After learning the MAC address of User A, the device starts to forward the packet. Because there is
no MAC address and port information of User B in the existing MAC address table, the device
forwards the packet to all ports except GigabitEthernet 1/0/1 to ensure that User B can receive the
packet.
Figure 21-3 MAC address learning diagram (2)
GEth 1/0/1
Geth 1/0/3 Geth 1/0/4
User A
User B User C