Abstract: A method and system for determining the connectivity of a virtual private network IP security (IPSec) tunnel between two network elements by originating a plurality of connection tests between the network elements. The first network element transmits a connectivity test message to the second network element over the secure tunnel upon receipt of an initiate connectivity test command. The secure tunnel includes two unidirectional tunnels. The second network element receives the connectivity test message over the first unidirectional secure tunnel and transmits a response back to the first network element over the second unidirectional secure tunnel. The number of successful responses received from the second network element are accumulated and the results are reported back to the source of the connectivity test command.

Abstract: A method and system for monitoring the status of an active secure tunnel between a pair of network elements in a communications network. The first network element originates and transmits an Internet Protocol Security (IPSec) test message to a second network element using a first unidirectional secure tunnel in response to the receipt of an active tunnel monitor command. The second network element receives the IPSec test message and transmits a response back to the first network element using a second unidirectional secure tunnel. The number of times that second network element failed to return a response to an IPSec test message is accumulated during a predetermined time interval and then compared with a threshold value to determine if the active secure tunnel has become disabled.

Abstract: A computer, and particularly a mobile client computer system, in which flexibility in use of the system is enhanced by a capability of receiving and dynamically recognizing a variety of what are here called docking options. Docking options are peripheral devices, such as radio transceivers, which can be selectively connected to and used with a mobile client system. A docked option is identified by an exchange of signals between the system and the option, accomplished through a plurality of input/output ports which together define an interface to the option.