INTRODUCTION

BACKGROUND

Components of Ground- Ground ATM voice systems has used digital (TDM/PCM - Time Division Multiplexing / Pulsed Code Modulation) or analogue technology during a long time.

Convergence of voice and data into one multimedia network is observed on the market. As a consequence the ATM communication network is evolving into a common infrastructure for voice and data services.

As a result of the above described technological trends, the capability of Voice over IP Technology may fulfil and improve operational and technical ATM communication requirements, including voice / data convergence, specific Quality of Services (QoS), security and safety requirements.

So after analysing the situation regarding:

• Operational and Technical Air-Ground (A/G) and Ground-Ground (G/G) ATM Voice system requirements

• Existing IP Voice protocols and signaling standards

• IP networks capability for Voice services

• Security, QoS, Convergence (infrastructure, protocol, applications)

• Existing IP Voice ATM systems and their service interfaces,

The following tasks were achieved for ground-ground ATM communications and ground-ground segment of air-ground ATM communications:

• Define IP Voice ATM Systems and identify their components (Voice Communication System / VCS, Ground based Radio Station / GRS...)

• Determine possible additional operational and technical ATM requirements for new IP Voice ATM systems, also taking into consideration A/G communications.

• Accordingly, make recommendations to upgrade current standardisation documents.

• Develop a Technical Specification for an IP Voice ATM System including:

o Minimum performance and safety / security requirements for the system and, if appropriate, for components

o Interoperability requirements between IP components of the IP Voice ATM systems

o Minimum performance requirements of an IP Network aimed to support Voice in ATM.

o Guidelines for qualification tests of IP Voice ATM systems and IP Voice ATM components.

So four documents with a common reference to "Vienna Agreement" was provided:

ED-136 VoIP ATM System Operational and Technical Requirements

ED-137 Interoperability Standards for VoIP ATM Components

ED-138 Network Requirements and Performances for VoIP ATM Systems

ED-139 Qualification tests for VoIP ATM Components and Systems

The "Vienna Agreement" defines the different components of the VoIP ATM system and may be resumed by the following figure on which are described the different interfaces between the components.