Voice over ATM: an evaluation of network architecture alternatives

This article describes eight application scenarios in which there is a business case for voice over ATM. It then evaluates alternative network architectures for implementing the required network functionality. The article incorporates much of the ongoing work of the ATM Forum and the ITU, but does not restrict itself to standards and implementation agreements. In addition, it evaluates nonstandardized alternatives for ATM transport of voice traffic. There are two main areas: N/spl times/64 kb/s structured data transfer, also known as composite cell transport-a network operator may aggregate individual voice calls into N/spl times/64 kb/s blocks for transport to an intermediate point in the network. At that point the individual calls need to be remapped into new M/spl times/64 kb/s blocks for the next stage of their transport. Architectural alternatives and advantages of remapping are investigated. Interworking of signalling is of two types: network interworking, in which the end users are connected to non-ATM networks and an ATM network is used for backbone transport; and service interworking, in which an ATM user is connected to a non-ATM user. Functionality and architectural alternatives for network and service interworking are evaluated.