Image Number 14 for United States Patent #6925062.
ATM test equipment are used as a source node and a responder node for conducting a test in a number of modes. At the source node, a test cell is formulated according to a selected test mode with a header identifying the source node and a responder node and a test mode value identifying the selected test mode, and transmits the test cell to an ATM network, and receives a response cell from the network to analyze data contained in the received response cell according to the test mode value of the response cell. The response cell is formulated at the responder node with a header identifying the responder node and the source node and the test mode value of the received test cell. At the responder node, data contained in the received test cell is also analyzed according to the test mode value of the test cell.