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Security | Network | Limit Control
Item
System Configuration
Indicates if Limit Control is globally enabled or disabled on the MP1204-XT. If globally
Mode
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.
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 uses 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
Aging Period
the MP1204-XT on which Limit Control is enabled. The end-host is allowed to forward if
the limit is not exceeded. Now suppose that the end-host logs off or powers down. If it was
not for aging, the end-host would still take up resources on the MP1204-XT and is
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 MP1204-XT 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 MP1204-XT.
Port Configuration
Port
The port number to which the configuration below applies.
Controls whether Limit Control is enabled on this port. Both this and the Global Mode
Mode
must be set to Enabled for Limit Control to be in effect. Note that other modules may still
use the underlying port security features without enabling Limit Control on a given port.
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 MP1204-XT is born with a total number of MAC addresses from which all ports draw
Limit
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.
76 - Configuration Pages
Configuration | Security | Network | Limit Control
RocketLinx MP1204-XT User Guide: 2000644 Rev. A
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