LandMARC is addressing a range of issues in the area of Video on Demand, and Quality of Service. A number of existing components that together provide an end-to-end QoS scenario, including a Video on Demand client and server (with support for RSVP), are being moved to Windows-based platforms. This is a continuation of work completed within the Eurescom project P702 and the ACTS project PeterPan. P702 investigated the support of user-initiated bandwidth-on-demand for the Internet, using Non-Broadcast Multiple Access (NBMA) networks to transport specific IP flows with a specified Quality of Service (QoS). The project worked on combining IPv6 and RSVP in order to allow the identification of IP traffic flows through the use of a flow ID (based on the combination of IPv6 source address and IPv6 flow label value). Flow label support was demonstrated to be beneficial as it avoided a full router table look-up during packet classification, thus offering reduced packet delay in routers. PeterPan furthered this work, addressing the issue of the convergence of RSVP and ATM. While the overall aim of the project was to develop an integrated functional architecture for edge and core network devices in order to efficiently support IP over ATM, Lancaster's focus was on the convergence of RSVP, ATM and IPv6. A Linux-based platform was developed enabling further performance comparisons to be made between IPv4 and IPv6, including end-to-end delay comparisons, and further router load calculations.
Further work includes the development of a transparent network cache for MPEG-2 streamed media. As technological advances continue to be made, the demand for more efficient distributed multimedia systems is also affirmed. Current support for end-to-end QoS is still limited; consequently mechanisms are required to provide flexibility in resource loading. One such mechanism, caching, may be introduced both in the end-system and network to facilitate intelligent load balancing and resource management.
New work within LandMARC is investigating the use of transparent network caches for MPEG-2 streamed media. A novel architecture is proposed, based on router-oriented caching and the employment of large scale dynamic RAM as the sole caching medium. The architecture also proposes the use of the ISO/IEC standardised DSM-CC protocol as a basic control infrastructure and the caching of pre-built transport packets (UDP/IP) in the data plane. In order to maximise throughput performance between RAM and the network interfaces, the node uses pre-built IP, which stores video data in memory in a pre-packetised format ready for immediate transmission by the network layer, thus avoiding the need for fragmentation or packet/header assembly.
As the work is in its infancy, the current focus is on the design and implementation of the caching architecture. An analysis of performance benefits will be reported in future publications.