Interlogix NS3502-8P-2S User Manual - Manual (Page 277)

IFS NS3502-8P-2S User Manual
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use the functionality.
The Aging Period can be set to a number between 10 and
10,000,000 seconds.
To understand why aging may be desired, consider the following
scenario: Suppose an end-host is connected to a 3rd party switch
or hub, which in turn is connected to a port on this switch on
which Limit Control is enabled. The end-host will be allowed to
forward if the limit is not exceeded. Now suppose that the
end-host logs off or powers down. If it wasn't for aging, the
end-host would still take up resources on this switch and will be
allowed to forward. To overcome this situation, enable aging.
With aging enabled, a timer is started once the end-host gets
secured. When the timer expires, the switch starts looking for
frames from the end-host, and if such frames are not seen within
the next Aging Period, the end-host is assumed to be
disconnected, and the corresponding resources are freed on the
switch.
Port Configuration
The table has one row for each port on the selected switch in the stack and a number of columns,
which are:
Object Description
• Port The port number for which the configuration below applies.
• Mode Controls whether Limit Control is enabled on this port. Both this
and the Global Mode must be set to Enabled for Limit Control to
be in effect. Notice that other modules may still use the
underlying port security features without enabling Limit Control
on a given port.
• Limit The maximum number of MAC addresses that can be secured on
this port. This number cannot exceed 1024. If the limit is
exceeded, the corresponding action is taken.
The stack switch is "born" with a total number of MAC addresses
from which all ports draw whenever a new MAC address is seen
on a Port Security-enabled port. Since all ports draw from the
same pool, it may happen that a configured maximum cannot be
granted, if the remaining ports have already used all available
MAC addresses.