ZyXEL Communications MES-2110, User Manual

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MES-2110 User’s Guide
127
C
H A P T E R
18
MAC
18.1 Overview
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.
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.
• 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.