ARRANGEMENT FOR TESTING PACKET SWITCHING NETWORKS

A packet network test arrangement where a test packet is transmitted from a test source to a test destination via successive nodes of the packet network. Any node that fails to receive acknowledgement within a predetermined time of transmitting the test packet to a subsequent node responds by transmitting information to the test source concerning the failure and particularly defining the involved nodes. Accordingly, a single test can be used advantageously both to detect faults and to localize such faults between two network nodes. The test arrangement also provides for the loop-around of test packets received at the test destination thus enabling the test source to verify successful packet communications.