Mac Management - Tripp Lite NGI-M08POE8-L2 Owner's Manual

5.2. MAC Management

Dynamic Address:
The MAC addresses are learnt by the switch. When the switch receives frames, it will record the
source MAC, the received port and the VLAN in the address table with an age time. When the
age time is expired, the address entry will be removed from the address table.
Static Address:
The MAC addresses are configured by users. The static addresses will not be aged out by the
switch; it can be removed by user only. The maximum static address entry is up to 256.
The MAC Table (a MAC table is also known as a filtering database) shows how frames are
forwarded or filtered across the Switch's ports. When a device (which may belong to a VLAN
group) sends a packet which is forwarded to a port on the Switch, the MAC address of the device
is shown on the Switch's MAC Table. It also shows whether the MAC address is dynamic
(learned by the Switch) or static(manually entered).
The Switch uses the MAC Table to determine how to forward frames. See the following figure.
1. The Switch examines the received frame and learns the port from 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 learnt in the MAC Table.
If the Switch has already learnt the port for this MAC address, then it forwards

the frame to that port.
If the Switch has not already learnt the port for this MAC address, then the frame

is flooded to all ports. If too much port flooding, it may lead to network congestion.
If the Switch has already learnt 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.
Notices:
The default MAC address table age time is 300 seconds.
The Maximum static address entry is 256.
Figure MAC Table Flowchart
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