Technical Report Input Fields

Principal Investigator:

Profs PT Kirstein and J Crowcroft









Address 1:

Gower St

Address 2:

Department of Computer Science, University College London




United Kingdom








Level Of Participation - Billed:

Prof Kirstein will spend 15%, with this amount billed to the project


Level Of Participation - Unbilled:

Prof Kirstein will spend 15%, not billed to the project

Prof Crowcroft will spend 20%, though this will not be billed to the project since he is paid full time by the University.

Project URL:


The primary purpose of the research project is to develop novel mechanisms for supporting and utilising Internet multicast conferencing. These goals include showing how to deploy new routing protocols with QoS path selection, developing multicast conferencing capability, providing mechanisms to permit a wide take-up of secure conferencing, bringing application-level relays into distributed operation, and developing new functionality for Multimedia Recording. A secondary purpose is to support the International Collaboration Board in developing and carrying out the program of collaborative research that they formulate.



For QoS Multicast forwarding, we have pursued the YAM approach, and the integration of PGM with CBT. Our adaptation of traffic level to the network environment is based on a belief that integrated services will take longer to deploy than formerly believed, and that. pricing work and differentiated services support the idea that adaptation will continue to be the best way to control quality and traffic load on the Internet. To this end, we have pursued three implementations and simulations on adaptation: a new protocol to give weighted proportional fairness to different users with no change to the intermediate routers, a reliable multicast transport protocol suitable for streaming data, and a one-to-many video or audio one using layered FEC - with a congestion control mechanism that shares the network fairly with TCP


For Resource Management in Forwarding Loop, we are experimenting with QoS controlled by signalling and admission control on the CAIRN Network. In view of the problems with RSVP, we have started development of RSVP Proxies and on Dynamic Sender-based Reservation.


In the area of Conferencing Tools, we are extending the UCL audio tool - RAT; the work includes on the operating system, lip synchronisation with video, general improvement in the tools and making the tools work well also on PCs under Windows. For tool control, we are concentrating on a control bus, with an implementation in VIC and RAT. The specification of private announcements of multicast sessions has been advanced, permitting both authentication and encryption..


We are pursuing the provision of an Application Level relay, which relays between Unicast and Multicast. The relay is able to do audio transcoding, and video multiplexing. We have studied the functionality of a UCL multimedia recorder, to allow it to be started from SDR using a plug-in that is distributed with the code, and to provide a better recording through distributed cache recorders.


We have continued to Chair the International Collaboration Board. There we have been attempting to identify worthwhile collaborative projects that the seven participating countries would sign up to supporting for a significant joint project.

Recent Accomplishments:


We have implemented, measured, and published the results of several new protocols. These include a version of TCP that can give weighted proportional fairness to different users with no change to the intermediate routers, and a reliable multicast transport protocol suitable for streaming data and one to many video or audio, that uses layered FEC and shares the network fairly with TCP.

We have made a software release which includes audio with wide-band speech, spatial locations of speakers, lip synchronisation, and private conferencing. An architecture for obtaining good record-ings from distributed caches has been developed and implemented.

Representatives of the Defence Departments of six countries in the ICB have agreed to collaborate on a secured VPN testbed supporting private conferencing, secured mail and secured web servers using IPv6 and IPSEC.

Current Plan:


Provide a full implementation and deployment over CAIRN of Session Initiation and Announcement, with its security aspects and the resulting security infrastructure - using IPSEC where appropriate.


Ensure that all the UCL multimedia conferencing components, including the Servers and relays, can be controlled in a secured way.


Provide an embryo Virtual Private Network between the partners in the International Collaboration Board, supporting Web access and multimedia conferencing.

Technology Transition:


The work we have done on QoS with CBT will be transferred to the NASA Qbone, with resulting impact on its development.


The secure conferencing and VPN will be used by the research arms of the ICB member countries to aid their understanding in how to set up Coalition networks in the manner considered necessary in future conflict situations.