PLANET GS-5220-16S8C - Manual (Page 261)

User’s Manual of GS-5220 Series
The Page includes the following fields:
System Configuration
Object 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 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.
261