Network support for multimedia applications using the Netlets architecture

Multi-party multimedia networking applications such as e-commerce, distributed data analysis, Internet TV and advanced collaborative environments feature stringent end-to-end Quality of Service (QoS) requirement and require globally distributed user groups to be interconnected. The variety of delivery requirements posed by such applications are best satisfied using highly customised networking protocols. Hence, a demand for networks to migrate from the current fixed service model to a more flexible architecture that accommodates a wide variety of networking services is emerging. New approaches are required in order to build such service oriented networks. Active networking is one such approach. Active networks treats the network as a programmable computation engine, which provides customised packet processing and forwarding operations for traffic flowing through network nodes. User applications can download new protocols into network elements at runtime, allowing rapid innovation of network services. This thesis makes the case for employing mobile agents to realise an active networking architecture, and describes such an architecture called the Netlets architecture. Netlets are autonomous, mobile components which persist and roam in the network independently, providing predefined network services. This thesis presents the design and implementation of the Netlet node and the service deployment m echanisms that are required to distribute Netlet services in the network. Using the Netlet toolkit, variety of network services were designed to provide network support for multimedia applications in the Internet. A service was implemented to enhance the working of the RSVP protocol in order to provide robust end-to-end QoS support even when the network is only partially QoS provisioned. A scalable and reliable multicast protocol was implemented using the unicast communication model that accommodate heterogeneous receiver terminals. Another service integrates client-side server selection support into web sessions established over the Internet. A service was also developed which provides QoS signalling support to legacy applications. It is shown that these Netlet services are of practical value using performance measurements to assess Netlet responsiveness. Netlet based solutions maybe deployed using existing technologies to provide support for a wide range of multimedia applications in the Internet. The Netlets architecture has thus been shown to allow value-added services to be added to existing networks. By optimising the Netlet architecture implementation, this may be extended to services operating on high-speed (1Gb/s and upwards) links. It thus shows promise as an architecture for building the next generation of active networking solutions

CLARA: A CLuster-based Active Router Architecture

Abstract — Personalization of web-based content coupled with a proliferation of heterogeneous terminals and devices will dramatically increase the need for computational services. Current trends towards thin clients make it difficult to perform such computation at the terminal end, while service providers frequently out-source computation, especially when operating under varying load. Today, most computational services utilize a traditional distributed systems model, which does not scale to Internet proportions. To alleviate this problem, we believe that computational services should instead be provided on a highly-distributed, besteffort basis, which has proven successful for packet routing in IP networks. In this paper, we describe an architecture that collocates routing and computational functionality, thereby providing a scalable computational service within a network. The prototype we have built utilizes multiple off-the-shelf PC’s to provide the necessary computational power. Initial experiments indicate that our proposed architecture can be utilized to perform real-time transcoding of video with minimal overhead. Moreover, the architecture does not incur any overhead on conventional IP routing. Keywords—cluster computing, active network, router architecture, multimedia streaming, MPEG transcoder I

A cluster-based active router architecture supporting video/audio stream transcoding services

Active routers allow computation to be performed within the network by processing packets when they pass through the routers. We design and implement a cluster-based active router system that provides multimedia stream transcoding service. The performance of the system is evaluated with three different load balancing schemes. We evaluate the out-of-order phenomenon and analyze the tradeoff between this phenomenon and the processing speed. We present a stream-based round robin algorithm for the transcoding service offered in the router and demonstrate its superiority over the conventional round-robin scheme. The main design criteria are to minimize the total transcoding time and maintain the order of media units for each outgoing stream. 1