Planet GS-5220 User Manual page 335

• Hold Time
Port Configuration
The table has one row for each port and a number of columns, which are:
Object
• Port
• Mode
• Limit
User's Manual of GS-5220 PoE Series Managed Switch
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 the remaining ports have already used all available MAC addresses.
335