Interlogix NS3550-2T-8S User Manual User Manual
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IFS NS3552-8P-2S AND NS3550-2T-8S User Manual
269
Figure 4-12-1: Port Limit Control Configuration Overview Page Screenshot
The page includes the following fields:
System Configuration
Object
Description
• Mode
Indicates if Limit Control is globally enabled or disabled on the switch stack. 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
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