Overview

The use of multimedia conferencing tools has become widespread within the business world. The opportunities offered by videoconferencing over a Wide Area Network have lead to the development of several tools – some at UCL under projects such as MECCANO – for use over fixed networks.

We are extending these tools to work within a mobile environment. The major issue raised by mobility is the sometimes dramatically reduced bandwidth and increased error rate between mobile hosts and the fixed network. A transcoding gateway is being produced that uses techniques such as frame dropping and image degradation to reduce the size of data sent over the link, and forward error correction to reduce the impact of errors.

The latest version of the Internet Protocol, IPv6, addresses this and other mobility issues. We have set up a mobile testbed using wireless networking and IPv6 to assess how well it meets our needs, and how our transcoding gateway can best fit into the network.

Security concerns are vitally important. Wireless links leave communications wide open to interception. But protecting the confidentiality of information using encryption causes problems for a transcoding gateway that needs access to the plaintext of the stream it is processing. A major focus of our work has been how active networks can cope with encrypted data.