As part of a broader organisational restructure, data networking research at Swinburne University of Technology has moved from the Centre for Advanced Internet Architecture (CAIA) to the Internet For Things (I4T) Research Lab.

Although CAIA no longer exists, this website reflects CAIA's activities and outputs between March 2002 and February 2017, and is being maintained as a service to the broader data networking research community.

Re-Engineering For Internet Telephony(REFIT)


Voice over Internet Protocol (VoIP) or Internet Telephony is an emerging technology that can be used as a platform for various communication media like voice, text messaging and video conferencing. As the Internet grows and broadband access technologies become increasingly available and widely adopted, VoIP has a potential to completely change a traditional telephone system and the way we use it. Cost-saving and flexibility are some of the advantages of VoIP technology which make this fundamental shift in telecommunications happen.

VoIP is generally cheaper than equivalent phone service over traditional telephone networks, especially for long distance calls and for users who could add VoIP traffic without additional cost using their existing data network. Furthermore, VoIP is more flexible as it allows users to make and receive calls anywhere in the world where Internet access is available. And more importantly, VoIP can integrate with other applications offered by the Internet to facilitate new functionalities and services.

However, there are many technical problems in VoIP that still need to be addressed. In particular, VoIP uses the Internet protocol to deliver its packets relying on a so call “best effort” service. As a result, real-time information of conversations via VoIP can be lost, delayed or out of order. Improving reliability and quality of service (QoS) in VoIP applications while keeping it cost-effective and flexible is therefore a challenging task. As VoIP is no longer confined to a fixed location or a subscriber’s identity, its nomadicity creates other problems in relation to the reliability of information, numbering and security. Other important issues that need to be studied are mobility, call management and signalling, and many more.

REFIT projects

In REFIT we will address fundamental technological challenges that pose problems for the deployment of VoIP services. In particular we will investigate: 

  • Improving QoS for VoIP, especially when the bottleneck is a last-hop wireless access link
  • Reliability in VoIP including issues related to power failure, network congestion or user mobility
  • Peering that includes numbering, addressing and call management in VoIP services
  • Security in VoIP
  • Implementation of VoIP including deployment strategy and network design.

Program Members

Hai Vu
Lawrence Stewart
Warren Harrop
Grenville Armitage



Last Updated: Monday 5-Jun-2006 18:34:29 AEST | Maintained by: Hai Vu ( | Authorised by: Grenville Armitage (