TELECOMMUNICATIONS NETWORK ARCHITECTURE FOR TRANSPORTING FAX, VOICE AND DATA VIA AN ATM SWITCH USING A CONVENTIONAL SIGNALING SYSTEM FOR CALL SET-UP

摘要

This proposal outlines an approach for interfacing Synchronous Transfer Mode (STM) and Asynchronous Transfer Mode (ATM) networks and for transporting voice, fax and voice-band data calls by the ATM network in an efficient manner. In contrast to the well known ATM Variable Bit Rate (VBR) approach, this proposal allows one to transport 64 kb/s traffic efficiently over ATM by re-using STM network signaling and exploiting the standard AAL-1-type adaptation layer (intended for Constant Bite Rate, CBR, services). We use low bit rate encoding algorithms and achieve additional compression for speech by marking cells that do not contain talk spurts. The invention defines specific rules for STM-to-ATM interfacing, including all routing translation, and identifies necessary Terminal Adapter (TA) and ATM switch capabilities. This approach is an advancement over previous inventions that specified network architecture and terminal adapter requirements to provide a graceful transition from an STM network (for example the AT&T long distance network) to an ATM network. Prior art described how to emulate an STM network in the ATM domain, but did not permit for compression and silence elimination and, therefore, did not allow achieving efficiency gains.