10/100 Fast Ethernet Switch User’s Guide
Switch Management
27
that Switch, in order to prevent the duplication of frames.
Frames transmitted between a pair of end stations can be
confined to LANs that form a path between those end
stations.
The functions that support the use and maintenance of
filtering database information are:
1.
Permanent configuration of reserved addresses.
2.
Explicit configuration of static filtering information.
3.
Automatic learning of dynamic filtering information through
observation of Switched Local Area Network traffic.
4.
Aging out of filtering information that has been
automatically learned.
5.
Calculation and configuration of Switched Local Area
Network topology.
Aging Time
The Aging Time is a parameter that affects the auto-learn process
of the Switch in terms of the network configuration. Dynamic
Entries, which make up the auto-learned-node address, are aged
out of the address table according to the Aging Time that you set.
The Aging Time can be from 10 seconds to 1,000,000 seconds. A
very long Aging Time can result with the out-of-date Dynamic
Entries that may cause incorrect packet filtering/forwarding
decisions.
In the opposite case, if the Aging Time is too short, many entries
may be aged out soon, resulting in a high percentage of received
packets whose source addresses cannot be found in the address
table.
