ZyXEL Communications MES3500-24 Benutzerhandbuch

MES3500-24/24F User’s Guide

This chapter introduces the MAC Table screen.

The MAC Table screen (a MAC table is also known as a filtering database) shows how frames are 
forwarded or filtered across the Switch’s ports. It shows what device MAC address, belonging to 
what VLAN group (if any) is forwarded to which port(s) and whether the MAC address is dynamic 
(learned by the Switch) or static (manually entered in the Static MAC Forwarding screen).

The Switch uses the MAC table to determine how to forward frames. See the following figure.

The Switch examines a received frame and learns the port on which this source MAC address came.

The Switch checks to see if the frame's destination MAC address matches a source MAC address 
already learned in the 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.

MAC Table Flowchart