Investigating the performance of audio/video service architecture. II. Broker network

For pt.1 see ibid., p.120-127 (2005). Increasing network bandwidth and computing power provide new opportunities for videoconferencing systems over Internet. In addition to homes and small officies, even the cell phones have broadband Internet access in the near future. Therefore, we can imagine that the trend in the increasing usage of videoconferencing systems continues. This requires universally accessible and scalable videoconferencing systems that can deliver thousands of concurrent audio and video streams. However, developing videoconferencing systems over Internet is a challenging task, since audio and video distribution requires high bandwidth and low latency. Current videoconferencing systems such as IP-Multicast and H.323 can not fully address the problem of scalability and universal accessibility. We propose service oriented architecture for videoconferencing, GlobalMMCS, and use an event brokering middleware, NaradaBrokering, to deliver real-time audio and video streams to high number of users. The performance of the event brokering network is critical to the success of this videoconferencing system. In this paper, we evaluate the performance of NaradaBrokering broker network in distributed settings in the context of audio/video delivery. The results demonstrate that even small number of brokers can deliver audio/video streams to more than a thousand users with very good quality. They also provide guidelines for the deployment of GlobalMMCS in particular, and they provide useful insights for the feasibility of using software based audio/video delivery systems in general