Abstract: A system and a method of operating the system for non-disruptively inserting a node into the operations of an ATM ring uses the ring operations to update topology information and routing tables at the existing nodes to include therein the new node and one or more virtual paths associated with the new node. Basically, the node to be inserted establishes communications with a ring hub node over an established intra-ring management channel. The node and the ring hub node then exchange information over the management channel and the node performs its initializing routines in order that the node may operate to pass through traffic on the existing virtual paths. The new node next requests from the hub node the assignment of one or more virtual paths for directing traffic between that node and other nodes on the network. In response to the request, the hub node assigns one or more virtual paths to the requesting node and establishes a signaling channel to the node over one of the virtual paths.

Abstract: A unidirectional ring operates in accordance with a call setup procedure in which a single node on the ring, referred to herein as the “hub node,” simultaneously (i) processes call setup information from and provides call setup information to an ATM network, and (ii) controls the call setup operations of the nodes on the ring. When a source node that is part of the ring initiates a call, the node directs a call setup message to the hub node. The hub node determines if there is sufficient bandwidth available on the ring for the call. If so, the hub node passes the call setup message to the ATM network, and simultaneously multicasts call setup information to the nodes on the ring. While the call setup message is progressing over the ATM network in a conventional manner, the nodes on the ring simultaneously set up the associated virtual path and/or virtual circuit and send back connection information to the hub node.

Abstract: A system with predefined primary and secondary routes sets up corresponding virtual circuits over both routes. A destination node maintains primary and secondary sets of routing tables that contain, respectively, routing information over each of the rings for every virtual circuit. A destination node disables the appropriate entries in the routing tables for the non-selected route, such that the node ultimately discards the traffic received over that route. To switch a virtual path, and thus all of the virtual circuits included therein, from the selected route to the nonselected route, the destination node disables and enables the appropriate entries in the primary and the secondary routing tables, to switch from using the set-up virtual circuits on the selected route to using the set-up virtual circuits on the non-selected route. To detect an event that triggers protection switching, such as path failure, the system uses “Continuity OAM cells” to provide path status information to the nodes.