This paper proposes an advanced ATM VP-based self-healing ring. This ring system offers better recovery control and path management than the conventional STM-based self-healing ring. This self-healing ring has two main characteristics. First, protection VP's are established in advance which have the same termination points as the working VP's regardless of the types of path connection. Recovery is accomplished by connecting the working VP's to their protection VP's at nodes adjacent to the failure point. This restores a failed path without internode negotiation. This network, therefore, realizes a simple recovery scheme. Second, recovery is executed in the ATM VP layer. A function to detect and remove the endless looping cells is not needed. The proposed architecture permits the flexibility of VP's to be applied to path management and recovery. The bandwidth of the protection VP's can be shared and effective VPI assignment is achieved. The proposed ring network reliably supports various broadband services in a cost-effective manner.>

A B-ISDN introductory scenario is described from the viewpoint of service, and a virtual-path (VP)-based access network architecture based on this scenario is discussed. In the access network each VP is dedicated to one service, such as a leased circuit, switched circuit, or video distribution. The concept and functions of a subscriber line terminal (SLT) to realize this capability are introduced. Asynchronous transfer mode (ATM) subscriber line system deployment and the main SLT functions are discussed.>