i3 International S81 User Manual page 48

Port Security Limit Control Configuration Parameters:
Items Description
Mode Indicates if Limit Control is globally enabled or disabled on the switch. If globally disabled, other
modules may still use the underlying functionality, but limit checks and corresponding actions
are disabled.
Aging Enabled If checked, secured MAC addresses are subject to aging as discussed under Aging Period.
Aging Period If Aging Enabled is checked then the aging period is controlled with this input. If other modules
are using the underlying port security for securing MAC addresses, they may have other
requirements to the aging period. The underlying port security will use the shorter requested
aging period of all modules that 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 and a number of columns, which are:
Port: The port number to 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
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