Task: A.2
Task Leader: UTS
Participants: UTS 4 mm, INRIA 1 mm, SICS 3 mm
From: T0+6 To: T0+24
Input from: A.1, D.1, D.2
Output to: B.2, C tasks, D.2, D.3
Deliverable: UTS-1 (Report): Dynamic protocol configuration
Due at: T0+24
Milestones: First draft at T0+12, second draft at T0+18
Description:
The objective of this work will provide a framework for
demonstrating the viability of using dynamically
adaptive communication software structures to
provide optimum performance under varying
application requirements and quality of service
provided by the underlying network.
To illustrate the dynamic changes in application requirements consider a computer supported collaborative work application between two users. If the two parties involved decide that the opinion of a third person is required, it will be necessary to re-arrange the screen layout and allocate system resources to the new connection. In this case, firstly, the rearrangement of the screen may result in smaller display window sizes, thus altering the application quality of service (QOS) requirements. Secondly, it may not be possible open the third connection while still maintaining the QOS specifications of the original two party dialogue.
Degradation in the service provided by the communication subsystem may result from end system resource limitations and/or deterioration of the links due to network anomalies. Under these conditions, it has been shown [20] [19] that it is possible to obtain performance improvements by varying the application QOS requirements. Therefore it appears that, if the communication system could dynamically adapt and compensate for the degradation in service, the user perceived performance could be further optimized.
This adaptivity can be achieved either through a processes of tearing down and re-establishment of connections or providing mechanisms for "on the fly" adaptivity. The latter has numerous advantages. Firstly, it will be possible to eliminate the handshaking associated with disconnection. Secondly, it will be possible to maintain data flow during the adaptation phase. Thirdly, in the case where the service being subscribed to has an associated connection charge, it could potentially reduce the costs.
This task will determine the generic (self contained) protocol functions that could be combined to provide the respective protocol functionality. This will involve the identification of the generic protocol functions, the determination of the inter- dependencies of the various protocol functions, and implementation issues, such as ILP. This work will be complementary to the work in WP C studying ILP and network architectures.