Plessey Overseas Limited

General Datacomm, Inc.

Ahead Communications Systems, Inc.

John Cumberton

Ronald P Novick

Xing Chen

Cuong T Luu

Alexander S Rae

Vernon J Fernandes

Michael McLoughlin

Ramanathan Ramanathan

Alun E Foster

Pasquale Cassella

Michael R Carter

The invention utilizes two-stage shaping and two-priority queuing thereby allowing both shaped and unshaped virtual circuits to be provisioned in a single virtual path. For each VP, a separate dynamic buffer is set up for each shaped VC and unshaped VC within the VP. The shaped cells stored in dynamic buffers are dequeued via VC scheduling (first stage shaper) to a high priority queue according to the shaped VC contracts, and the unshaped cells stored in dynamic buffers are dequeued in a round robin manner to a low priority queue. The outputs of both the high priority queue and the low priority queue are passed to a second stage shaper where cells from the high priority queue are scheduled according to the VP contract, and cells from the low priority queue are also scheduled according to the VP contract, but only when VP bandwidth is not being used by the high priority cells. In order to avoid overrunning the high priority queue in the second stage, the iPSR (Peak Shaping Rate increment) of the CBR VCs in the VP is chosen to be the iSSR (Sustained Shaping Rate increment) of the VP. The iPSR of the CBR VCs in the VP can be chosen to be higher than the iSSR of the VP as long as cell loss is not experienced at the second stage caused by overrunning the high priority queue. In addition, the calculated bucket for CBR service in the first stage is made a function of the Peak Cell Rate (PCR) of the VP.

Multi-tiered shaping allowing both shaped and unshaped virtual circuits to be provisioned in a single virtual path

A SS7 signalling router receives SS7 signalling regarding narrowband calls to be routed over the ATM network. When the SS7 router receives signalling from the SS7 network, it does not process the signalling, but reads the originator point code (OPC) and forwards the signalling via the ATM network to the ATM switch which is attached to the originator of the message. An interworking function (IWF) at the ATM switch processes the SS7 signalling by generating the appropriate ATM signalling to set up a circuit between the originating ATM switch and the destination ATM switch. The IWF at the originating ATM switch also processes the SS7 signalling by returning it to the SS7 router with the destination point code (DPC) of the PSTN switch coupled to the destination ATM switch. When the SS7 router receives an SS7 signalling message from an ATM switch, it forwards it to the SS7 network where it is sent to the DPC. The IWF at each ATM switch is preferably distributed among several processors including a signalling VSM controller (an SVSM), a plurality of VSM controllers and an ISUP controller. SS7 SUs enter the SVSM controller which separates MSUs from FISUs and LSSUs. The MSUs are sent to the ISUP controller which interrogates the CIC of the IAM messages and forwards the IAM information to the appropriate VSM controller for narrowband to broadband conversion.

Methods and apparatus for transporting narrowband (voice) traffic over a broadband (ATM) network

A data transmission system in which data is transmitted in a form incorporating additional data providing for error correction at the receiver. The data is encoded in a transmitter using a signal mapping system which maps a number of original digits and also digits produced by a convolutional encoder. The data at the receiver is decoded using hard and soft decision decoding which can correct errors in the received data.

Soft decision convolutional code transmission systems

Growing community of inventors

Danbury, CT, United States of America

John Cumberton