User manual

APS User Manual
300
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
Port: Physical port of the switch.
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 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.
Action: If Limit is reached, the switch can take one of the following actions:
None: Do not allow more than Limit MAC addresses on the port, but take no
further action.