Arrangement for synchronization of a stream of synchronous traffic delivered by an asynchronous medium

Abstract

An ATM cell constructor ( ) of an ATM transmitter assembles a stream of frames of constant bit-rate traffic received on a listen TDM bus ( ) into cell payloads ( ) using ATM adaptation layer (AAL ). Once every eight cells, the AAL structured data transfer (SDT) cell constructor layer ( ) introduces a one-octet SDT offset pointer ( ) into the payload. This pointer designates traffic-block (TDM frame) boundaries. The payload with an attached ATM header forms an ATM cell, and the constructor transmits a stream of the ATM cells to an ATM cell deconstructor ( ) of an ATM receiver. The deconstructor disassembles the payloads of the received ATM cells and transmits the stream of frames of constant bit-rate traffic on a talk TDM bus ( ). In response to each received SDT offset pointer, the deconstructor's time slot interchanger (TSI ) resets to the start of frame-processing, thereby aligning frames formed by the TSI with the received frames. The deconstructor ( ) detects occurrence of TDM frames on the talk TDM bus and synchronizes (aligns) transmission of the frames formed by the TSI with the TDM frames on the talk TDM bus. The listen and talk TDM buses are thereby synchronized with each other.