Lucent Technologies Inc.

At&t Bell Laboratories

At+t Corp.

P Harshavardhana

Bharat Tarachand Doshi

Kathleen S Meier-Hellstern

Arik Kashper

Steven S Katz

N Farber

Rajiv Kapoor

Subrahmanyam Dravida

Thomas S Giuffrida

David S Einstein

Thomas S Guiffrida

An Asynchronous Transfer Mode (ATM) network comprising a plurality of ATM switches may be arranged so that it receives calls from Synchronous Transfer Mode (STM) switches that employ in-band signaling by first converting in-band signals received from an STM switch to an out-of-band signaling message and then transmitting the message to the ATM switch that will route the associated call toward its destination. At an interface which interfaces the ATM switch with the out-of-band signaling network, the contents of the received message are converted to a form suitable for presentation to the ATM switch. For example, the identity of the trunk over which the call will be routed from the STM switch to the ATM switch is converted to a virtual channel identifier.

ATM network arranged to interface with STM in-band signaling

An Asynchronous Transfer(ATM) network comprising a plurality of ATM switches may be arranged so that it receives calls from Synchronous Transfer Mode (STM) switches that employ out-of-band signaling such that the ATM switches communicate telephone call signaling information between each other and the STM switches via an out-of-band signaling network associated with the ATM network and interface with out-of-band networks associated with the STM switches.

ATM network architecture employing an out-of-band signaling network

An Asynchronous Transfer Mode (ATM) network comprising a plurality of ATM switches may be arranged so that it may receive for routing telephone calls originating at Synchronous Transfer Mode (STM) switches. This may be done in the ATM network by accumulating voice signals as they are received from a STM switch and forming an ATM data-cell payload when the accumulation includes a predetermined number of the voice signals, e.g., 48 voice signals. The payload and a header, including a virtual channel identifier determined as a function of the identity of the STM trunk over which the voice signals were received, may then be supplied to an associated ATM switch for routing to an intended destination.

Terminal adapter for interfacing an ATM network with a STM network

Congestion in a high speed connection oriented packet network carrying bursty data and real time service is avoided by a novel in-call negotiation scheme for reserving bandwidth for real time calls and reserving buffer capacity for bursty calls. For a real time call, a centralized call controller in each switch in the network determines which of its outgoing trunks has available to it the peak bandwidth needed to accommodate the call. Once one of these trunks is found, the call routing is set up so that the call is directed through that trunk and the peak bandwidth requirement of the call is allocated on that output trunk for the duration of the call. The network contains one or more switches, each of which has a centralized call controller and a plurality of trunk controllers. The call controller routes calls from a plurality of input trunks to a plurality of output trunks, identifies kinds of calls, and allocates bandwidth on the output trunks. The trunk controllers perform in-call buffer reservation independent of the routing, identification, and bandwidth allocation performed by the call controller. This relieves the call controller of the extra burden of performing buffer reservation and it permits buffer reservation to be accomplished in a shorter period of time.

Congestion control for high speed packet networks

A congestion control scheme for connectionless networks relieves congestion by routing a portion of traffic on a congested primary path onto a predefined alternate path constructed such that loop-freedom is guaranteed. Explicit care is taken to avoid spreading congestion onto alternate paths. The control actions are taken in a completely distributed manner, based on local measurements only and therefore no signaling messages need to be exchanged between nodes. If desired, lower loss priority may be assigned to alternate routed traffic. Congestion is monitored locally and thresholds defined to declare the onset and abatement of congestion. The present invention affords at least an order of magnitude improvement in end-to-end cell blocking under sustained focussed overload.

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Freehold, NJ, United States of America

P Harshavardhana