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:


This research wants to show how to build novel, hyper-scaleable applications and services using state-of-the-art Application Level and Network Level Active Networking technology. The infrastructure services to be built within this environment will themselves be scaleable, and offer meta-services, such as application level multicast and mobile routing and load balancing, off which other applications and services may leverage. We plan to control the usage of integrated resources like differentiated services and bandwidth brokers, and to support multicast. We plan to build an integrated architecture that factors in authentication, confidentiality and accounting, using the current mechanisms being standardised in the IETF - and will contribute to the Standardisation process. We plan to apply the Active Service techniques to a problem of considerable interest, viz. the monitoring of a substantial number of speech sources.



In earlier work, UCL has developed an Application Level Active Network system, based on mechanisms called "proxylets" which are loaded throughout a distributed set of dynamic proxylet servers to enhance an internet service in a programmable way. For many classes of large-scale application, this allows one the further enhancement of the scale of participation (both in the number of participants and in the range of performance seen in a heterogeneous network). A number of components in this architecture are not yet available. One such set of modules is that of filters/transcoders where there are impedance mismatches in the bandwidth, and where simple source-based layered coding techniques are not appropriate. A good example is when the mismatch is so big that the usual exponential distribution of rates of audio or video is much larger than the actual steps in available bandwidth.


In previous work we have developed a number of active network components, which are important in achieving a Quality of Service (QoS) for multimedia applications. Many of these components require up-dating in view of recent advances in algorithms, architecture and protocols. As another part of our programme, we will implement some of these components in JAVA, ensuring the efficiency and safety of the active elements. Since we are prototyping within the JVM, it will be necessary to apply additional measures to ensure that the components are trustworthy.


Mere design of a language and implementation of components is not enough. As a final step we will deploy the active components, using multimedia applications from other projects, to demonstrate that appropriate Quality of Service can be attained, in a safe way. This deployment will include aspects of secure configuration management - which will investigate the advantages of using secure forms of CORBA in the activity.

Recent Accomplishments:

New Start

Current Plan:


Development of a two-level architecture, with information sharing between the levels the Dynamic Proxylet Servers and the IP Routing levels share information about topology, load and policy. It will include: Intra-domain proxylet services (e.g. congestion control, object location and reservation), Inter-Domain Proxylet Services (e.g. pricing agent, certification agent), and security services (e.g. digital watermarking, signed code).


As a component, we will develop an upgraded version of the transcoding gateway in Java, and adopt a remote multicast proxy suitable for more flexible control, and where necessary, security functionality.


We will complete the implementation of an active service framework on which the components and their services can be mounted.

Technology Transition:

New Start