Abstract: Methods for determining at least two pre-computed paths to a destination in a communications network are provided. The two paths are maximally disjoint. Maximally disjoint paths are paths where the number of links or nodes common to the two paths is minimized. This minimization is given a priority over other path considerations, such as bandwidth or cost metrics. By pre-computing a maximally disjoint pair of paths, the probability that an inoperable link or node is in both paths is minimized. The probability that the inoperable link or node blocks a transfer of data is minimized. Additionally, a pair of maximally disjoint paths is determined even if absolutely disjoint paths are not possible. The communications network may include at least four nodes, and maximally disjoint pairs of paths are pre-computed from each node to each other node. A third path from each node to each other node may also be computed as a function of bandwidth or a cost metric.

Abstract: The invention comprises a series of architectures that are implemented in four phases to provide a migration path from an initial ATM service offering to a full service ATM network. The initial ATM network includes several metropolitan ATM networks that are interconnected by a core ATM network. Each metropolitan ATM network includes a service node that controls ATM network elements to deliver services. In Phase I, a business hub that is connected to the metropolitan ATM network integrates voice, data, and Internet traffic over a single ATM connection that contains permanent Virtual Connections (PVCs) to various destinations, such as other business hubs, a gateway to local and long distance networks, the Internet, a frame relay network. In Phase II, the architecture is extended to smaller business markets. Businesses are provided with the PVC-based ATM service using xDSL/ATM connections that are multiplexed at a central office and then provided to the service node over the metropolitan ATM network.

Abstract: The invention is an ATM communications system that provides the option of advanced communications services or conventional telephone service to the customer. Advantageously, the ATM communications system does not require the widespread deployment of class 5 telephone switches to provide telephone service. A residential communications hub is located at a residence and communicates with the telephones at the residence using the analog telephony format. The residential communications hub converts between the analog telephony format and the ATM format. The residential communications hub is connected to a DSL mux by telephone wiring that carries the ATM/DSL format. The residential communications hub and the DSL mux communicate using the ATM/DSL format. The DSL mux converts between the ATM/DSL format and the ATM/SONET format. The DSL mux is connected to the an ATM switch by a broadband connection that carries the ATM/SONET format. The DSL mux and the ATM switch communicate using the ATM/SONET format.

Abstract: An ATM reference traffic system records packet information representative of ATM packets transmitted over an ATM network. The system also creates and transmits ATM packets from packet information on a schedule representative of ATM packet transmission over an ATM network. The preferred system uses a personal computer with the operating system modified to schedule events with microsecond resolution while providing interrupts to the operating system on a periodic basis.