Design and implementation of distributed multimedia session manager for efficient multi-point applications

Many multi-point applications become more efficient when they use branch servers (servers that function as branches of a user's system) in the network. For example, efficient multi-point teleconferencing is realized by using multi-point control units as branch servers. HTTP-based file distribution becomes efficient by using mirror file servers as branch servers. We propose a multimedia session manager (MSM) as a network functional entity that manages resources of branch servers distributed in the network and present its design and implementation. MSM is designed with the session and resource concept which is quite comparable to the service session concept in the TINA service architecture. Hence, MSM can be considered as one implementation of the TINA's service architecture concept with the focus on the management of higher-layer resources, such as the MCU, for multi-point applications. The presented MSM achieves scalability through an implementation with distributed CORBA objects. Furthermore, by taking advantage of the similarities among multi-point applications using branch servers, it can be adapted easily to various network services. Hence, using MSM, we can rapidly create a new network service for a new multi-point application. Finally, we show examples of a network service using MSM. Such a network service reduces the ineffective use of network bandwidth and alleviates traffic concentration on a user (application service provider). As a result, it reduces the total cost of the applications.