This invention relates generally to the field of communications and, more particularly, to a system and method for communicating telecommunication information using asynchronous transfer mode (ATM).
The public switched telephone network is a circuit-switched network that uses dedicated lines to communicate telephone calls. At a central office, a digital Class 5 switch receives analog telephone signals from a user, digitizes the analog telephone signals, and then multiplexes the digital signals over a network of circuit-switched backbone transport lines. An interexchange carrier (IXC) transports the call to a destination Local Access and Transport Area (LATA), where it is handed to a local service provider and reconverted to an analog signal for delivery to a second user.
New broadband communication protocols, such as ATM, have emerged that allow the delivery of telephone calls using data packets. Although ATM Adaptation Layer type 2 (AAL2) is best suited for delay sensitive applications, such as communicating voice or other telecommunication information to customer premises, many broadband service providers do not support end-to-end AAL2 service to customer premises. As a result, this lack of support for AAL2 quality-of-service has hindered widespread deployment of voice over ATM.
In accordance with the present invention, a system and method for communicating telecommunication information using ATM is provided that substantially eliminates or reduces disadvantages or problems associated with previously developed systems and methods.
In one embodiment, a gateway for communicating telecommunication information between a telecommunication network and customer premises equipment includes a telecommunication interface and a packetization module. The telecommunication interface receives first telecommunication information for a first subscriber and second telecommunication information for a second subscriber. The packetization module generates first ATM cells for communicating the first telecommunication information using a first ATM adaptation layer associated with the first subscriber and generates second ATM cells for communicating the second telecommunication information using a second ATM adaptation layer associated with the second subscriber.
In another embodiment, a gateway for communicating telecommunication information between a telecommunication network and customer premises equipment receives telecommunication information from the telecommunication network for communication to the customer premises equipment. The gateway generates AAL2 information encapsulating the telecommunication information, generates ATM cells encapsulating the AAL2 information, sets a field in each ATM cell to indicate that each cell includes an end of a data unit, and communicates the ATM cells to the customer premises equipment.
The present invention provides a number of important technical advantages. Unlike previous techniques, the present invention provides a gateway that communicates telecommunication information using alternative ATM adaptation layers. As a result, if a broadband distribution platform between the gateway and a subscriber""s customer premises equipment supports end-to-end AAL2 service, gateway 18 may communicate the subscriber""s telecommunication information using AAL2. But, if the broadband distribution platform does not support AAL2, the gateway may communicate the subscriber""s telecommunication information using AAL5 or any other suitable AAL type. In addition, if AAL2 is not available, the gateway may communicate the subscriber""s telecommunication information using a hybrid AAL2/5 that provides significant advantage over AAL5. For these and other readily apparent reasons, the present invention represents a significant advance over prior art systems and methods.