Planet IGS-10020HPT-U User Manual page 307

The page includes the following fields:
System Configuration
Object
• Aging
Enabled
• Aging Period
• Hold Time
Port Configuration
The table has one row for each port and a number of columns, which are:
Object
• Port
• Mode
• Limit
Description
If checked, secured MAC addresses are subject to aging as discussed under
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.
The hold time - measured in seconds - is used to determine how long a MAC address is
held in the MAC table if it has been found to violate the limit. Valid range is
between 10 and 10000000 seconds with a default of 300 seconds.
The reason for holding a violating MAC address in the MAC table is primarily to ensure that
the same MAC address doesn't give rise to continuous notifications (if notifications on
violation count is enabled).
Description
The port number for which the configuration below applies.
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.
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
User's Manual of IGS-10020HPT-U
307
Aging