Elements and Functions of a MAC Address Table
Elements
Each entry in a MAC address table is identified by a MAC address and a VLAN ID or virtual switch interface (VSI). The destination host's MAC address can be bound to multiple VLAN IDs or VSIs in the MAC address table if it joins multiple VLANs or VSIs. Table 2-2 lists four example MAC address entries with their associated VLAN ID/VSI names and outbound interfaces. For example, the first MAC address entry is used to forward the packets destined for 0011-0022-0034 and VLAN 10 through outbound interface GE3/0/1.
MAC Address |
VLAN ID/VSI Name |
Outbound Interface |
|---|---|---|
0011-0022-0034 |
10 |
GE3/0/1 |
0011-0022-0034 |
20 |
GE2/0/4 |
0011-0022-0035 |
30 |
Eth-Trunk 20 |
0011-0022-0035 |
huawei |
GE2/0/5 |
Functions
The MAC address table is used for unicast forwarding of packets. In Figure 2-1, when packets sent from PC1 to PC3 reach the switch, the switch searches its MAC address table for an entry matching the destination MAC address and VLAN ID of the packet. In this example, it finds that MAC3 and VLAN 10 correspond to the outbound interface Port3. The switch then forwards packets to PC3 through Port3.
