Asynchronous Transfer Mode (ATM) is considered to bo the key technology for realizing B-ISDN. This paper discusses current research on ATM switching nodes for high-speed communication networks. Although some ATM switching nodes have been deployed, much work continues for resolving problems as regards operations and maintainability, such as ATM layer performance evaluation including layered management scheme upon detection of line failure, function test methods regarding channel connectivity for multicasting, and real-time ATM traffic-monitoring mechanism with QoS control. To achieve sufficient ATM node maintainability, the ATM cell transfer quality on the VP and VC levels should be ensured both within the ATM node and between adjacent ATM nodes. Since ATM switching nodes handle many kinds of Virtual paths and virtual channels, each channel's connectivity must be confirmed. This paper proposes ATM layer performance evaluation concept, layered management scheme upon detection of line Failure, function test methods for a multicast switch using test cells that periodically pass through pre-determined switching path routes. It also proposes the concept of test cell generation For simulating multiplexed ATM test cells taking ATM traffic characteristics into account. Furthermore, this paper describes a fault diagnosis scheme using test cells that can continually observe the entire ATM connection length in the system. A real-time traffic monitoring hardware configuration and an interface with soft ware control are also discussed and it is clarified that the required functions can be realized by using commercially available DSPs.