Abstract: A method and system for monitoring a first virtual circuit in an asynchronous transmission mode (ATM) network comprises the steps of establishing in the network a second virtual circuit with the same path and QoS parameters as the first virtual circuit, and monitoring the first virtual circuit by determining the QoS parameters of the second virtual circuit. Specifically, a monitoring station determines the QoS parameters of the second virtual circuit by inserting monitoring information in cells transmitted and received on the second virtual circuit. The monitoring station inserts the monitoring information immediately before transmitting each cell and immediately after receiving each cell. Furthermore, the monitoring station compares the QoS parameters of the second virtual circuit with the QoS parameters of the first virtual circuit to determine network alarm information.

Abstract: Management packets are defined that are modified in the payload by each node along a virtual connection and are used to measure both end-to-end QoS and specific individual intermediate node performance parameters. Management packets are implemented by defining entirely new packets or by modifying ATM OAM cells. Switches or routers for use as intermediate nodes are defined that modify the payload of the management packet and locally measure packet delay and packet loss. An intermediate node measures and records the difference between the arrival and departure times of management packets at that switch utilizing delay-stamp fields within the management packets and either the switch internal routing header or timestamp fields within the packet. At the endpoint of the virtual connection, delay-stamp fields in the management packet indicate individual node delays and the cumulative delay.

Abstract: The present system provides a means to record an image of an item which is extremely difficult to inspect because of its peculiar shape or because the person who is inspecting it cannot come in close proximity thereto, such as red hot glass being measured for form and size immediately upon being formed into a bottle. The present system employs a television camera and logic circuitry to electronically compare the profile of said image against a standard item whereby the item being inspected or measured can either be rejected or accepted.