Voice Experiments in the UNIVERSE Project

摘要

In the UNIVERSE project,experiments were conducted on a series of Cambridge Ring LANs linked together by (a)satellite bridges(b) local bridges.The Cambridge Ring is a slotted ring which has the considerable advantages for packet voice,when compared with for example CSMA systems,that(1)efficient transmission of small packets is feasible(2)the ring inherently shares bandwidth amongst contenders in a manner favourable to voice in an ISDN environment.An adaptive packet voice protocol (which adjusts to the load and jitter conditions which prevail during the course of any particular call) has been designed,implemented and tested.It proved to be resilient and to give satisfactory sound quality whilst running through bridges,the bridges being subjected to widely varying loads.Design requirements for bridges/gateways in an ISDN,which have to bear both voice and data traffic,are discussed in the light of experience with this protocol.