Abstract: A solution for emulating a hardware device is provided. In particular, a communication device that includes a standard mode of operation and a mapping mode of operation is used together with a control program to emulate communication with the hardware device. The mapping mode of operation is used to implement communication functionality that requires hardware, while the control program emulates other communication functionality previously provided by the hardware device. As a result, a protocol, such as a channel protocol, that requires hardware functionality can be successfully emulated using both the control program and the communication device.

Abstract: A packet communications network includes a route testing system which launches a plurality of route testing messages from the source node to each of the nodes along the route, including the destination node, and returning to the source node. Time stamps in each of theses testing messages are compared to reception times to determine round trip delays which can be halved and compared to determine link transit times. These link transit times can, in turn, be analyzed to localize congestion or identify failed resources. The source resource is where the data is accumulated for the entire path and then analyzed to determine the location of failed links, if any, the response time from the source to the destination, the response time of each resource in the path, and the location of congested links. Packet switched resources identify the path test command themselves and carry out the testing procedure. Circuit switched resources utilize the control point controlling that resource to carry out the testing procedure.

Abstract: A method and apparatus for allowing the higher layers of two nodes on a connection that uses an asynchronous link protocol to synchronize the exchange of messages so that, without knowledge of the lower data link protocols, the protocols at higher layers can complete when the data link protocols are also complete. The upper layer of a node sends messages for transmittal to another node to the lower layer of its node and receives messages from another node via the lower layer of its node. A first message, including an initiator flag is sent from the upper layer of the first node to the lower layer of the first node. In response, the lower layer transmits a second message including the initiator flag from the first message to the lower layer of the second node. The second message is transmitted as a command or a response in accordance with the send process state of the lower layer of the first node.