Chapter 23 Mac Table; Introduction To Mac Table; Figure 87 Mac Table Filtering Flowchart - ZyXEL Communications AAM1212 User Manual

This chapter introduces the MAC Table screen.

23.1 Introduction to MAC Table

The MAC table lists device MAC addresses that are dynamically learned by the AAM. The
table shows the following for each MAC address: the port upon which Ethernet frames were
received from the device, to which VLAN groups the device belongs (if any) and to which
channel it is connected (for devices connected to DSL ports).
The switch uses the MAC table to determine how to forward frames. See the following figure.
1 The switch examines a received frame and learns the port on which this source MAC
address came.
2 The switch checks to see if the frame's destination MAC address matches a source MAC
address already learned in the MAC table.
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•
•

Figure 87 MAC Table Filtering Flowchart

Chapter 23 MAC Table

If the switch has already learned the port for this MAC address, then it forwards
the frame to that port.
If the switch has not already learned the port for this MAC address, then the frame
is flooded to all ports. Too much port flooding leads to network congestion.
If the switch has already learned the port for this MAC address, but the destination
port is the same as the port it came in on, then it filters the frame.
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