Method for trunk line duplexing protection using a hardware watchdog
The present invention relates to a method for switching dualized trunk lines, more particularly a method for switching dualized trunk lines using a hardware Watchdog function in communication equipments. According to the present invention, trunk interfacing boards are dualized so that a failure of the board does not lead to a failure of the trunk, and switching trunk resources is performed regardless of the failure status of a CPU. More specifically, a method for switching dualized trunk lines using a hardware Watchdog function, comprises the steps of: only monitoring the status of dualized boards via interfaces by a CPU between dualized trunk boards and between processors; performing a response function for a Keep Alive Signal received via trunk line sin real time not to affect a line bandwidth; performing a function for checking a line status and a function for cleaning a Watchdog register at the time of the response; resetting a Watchdog Timer by a sense device register monitoring logic when the CPU writes, which is configured by means of hardware; and generating a timeout in the Watchdog timer in the event that the CPU cannot perform a cleaning operation on the Watchdog register for a predetermined time, thereby switching line sand restarting resources within boards including the CPU. Accordingly, the present invention is a method for switching dualized trunk lines using a hardware watchdog function, which can be applied to a physical line interfacing that requires stability and reliability.
1 . A method for switching dualized trunk lines using a hardware Watchdog function, comprising the steps of:
only monitoring the status of dualized boards via interfaces by a CPU between dualized trunk boards and between processors;
performing a response function for a Keep Alive Signal received via trunk lines in real time not to affect a line bandwidth;
performing a function for checking a line status and a function for cleaning a Watchdog register at the time of the response;
resetting a Watchdog Timer by a sense device register monitoring logic when the CPU writes, which is configured by means of hardware; and
generating a timeout in the Watchdog timer in the event that the CPU cannot perform a cleaning operation on the Watchdog register for a predetermined time, thereby switching lines and restarting resources within boards including the CPU.
2 . A method as claimed in claim 1 , the maintenance for dualized trunk lines is configured so that both an Active/Standby (CPU Restart) type and an Load Share (CPU not Restart) type are possible, and can select overall trunk resources using inter negotiation signals at the time of initial Running;
a default at the time of Dual Running maintains the number of selectable resources with a predetermined ratio, which can be controlled by software;
in the event that trunk resources are beforehand serviced in a Pair Side Board, the maintenance is performed in a way that the forgoing master controls by means of software control.
3 . A method as claimed in claim 1 , the dualization method using the Watchdog, comprising the steps of:
determining whether a Link Enable Register specific bit is available after reset;
if the bit is unavailable, terminating a Watchdog timer operation for the specific trunk, and if available, matching the timer value of the specific trunk with the value of the Watchdog timer for the trunk;
after matching, decreasing the value of the specific trunk timer by one by applying second timer pulses;
if the value of the specific trunk timer becomes zero after decreasing by one, cleaning the specific trunk timer, and at the same time, after disabling the specific trunk timer, switching the link of the specific trunk; and
after switching the link, terminating the Watchdog timer operation for the specific trunk.