Abstract: A packet communications network includes both packet switched and circuit switched transmission links. A path test command launched from a source resource on the network to a destination resource follows a current path from the source to the destination. At each resource, the path test command initiates a process which identifies the next resource in the path, the port of the current resource through which the next resource is accessed, and the current time. This data is returned to the source resource 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.