Introduction to Multicast Technology

The multimedia communication over the Internet needs the multicasting delivery scheme. In this chapter the sophisticated group management and routing protocols required for multicasting are presented. The different kinds of transport protocols for satisfying the special requirements of the multimedia applications are also included. Finally the current design principles of the multicast-based multimedia applications are discussed.

A Model for Dynamic QoS Negotiation Applied to an MPEG4 Applications

The traffic generated by multimedia applications presents a great amount of burstiness, which can hardly be described by a static set of traffic parameters. The dynamic and efficient usage of the resources is one of the fundamental aspects of multimedia networks: the traffic specification should first reflect the real traffic demand, but optimize, at the same time, the resources requested. This chapter presents: a model for dynamically renegotiating the traffic specification (RVBR), how this can be integrated with the traffic reservation mechanism RSVP and an example of application able to accommodate its traffic to managing QoS dynamically. The remainder of this chapter focuses on the technique used to implement RVBR) taking into account problems deriving from delay during the renegotiation phase and on the performance of the application with MPEG4 traffic.

Mobile Multimedia over Wireless Network

In the last few years the rapidly growing Internet has pushed new multimedia applications in the field of entertainment, communication and electronic commerce. The next step in the information age is the mobile access to multimedia applications: everything everywhere any time! This tutorial chapter addresses a key point of this development: data transmission for mobile multimedia applications in wireless cellular networks. Addressed networks are existing standardized terrestrial wireless systems such as GSM, D-AMPS, IS-95 and PDC, including their evolutions HSCSD, GRPS, HDR, IS-136+ and IS-136HS. Furthermore, proprietary satellite networks like Orbcomm, Globalstar, ICO, Ellipso and Courier are considered. Finally, future high bandwidth terrestrial/satellite third-generation systems based on the UMTS standard, as well as future proprietary systems like Astra-Net, Skybridge, Teledesic and Spaceway, are discussed. For each of these networks, an overview on the data channels is given with respect to their capacity, temporal organization, error characteristic, delay and availability. Further, the architecture, the functions and the capacities of the mobile terminals are reviewed. Having studied this chapter, the reader is able to answer questions like: · Which network will be capable to transmit real-time video? · Does a rainfall interrupt my mobile satellite Internet connection? · When will high bandwidth, wireless networks be operational? · How to tune existing multimedia applications to be efficient in wireless networks? The chapter is closed by a glossary of terms, a reference list to in-detail literature and a list of Web sites of companies and organizations providing useful information.

IP Multicast

Without doubt, multicast communication as a means for one-to-many or many-to-many delivery of data has become a hot topic in multimedia environments. A lot of people are interested in multicast: the research community, standards groups and Internet Service Providers (ISP) among them. Although IP multicast is a very good solution for Internetworking multimedia in many-to-many communications, there are still issues that have not been completely solved. Protocols are still evolving and new protocols are constantly coming up to solve these issues because that is the only way for making multicast become a true Internet service. The main goal of this chapter is to describe the evolution of IP multicast from the obsolete MBone (Multicast Backbone) and intra-domain multicast routing to the actual inter-domain multicast routing scheme. We will pay special attention to the challenges and problems that need to be solved, the problems that have been solved and the way they were solved. We will make a complete picture of the state of the art explaining the idea behind each protocol and how all those protocols work together.

A Layered Multimedia Presentation Database for Distance Learning

Multimedia presentations are suitable for instruction delivery. In a distance learning environment, multimedia presentations are lecture materials to be broadcasted among a number of workstations connected by networks. In order to manage these course materials efficiently, a multimedia database management system (MDBMS) is essentially important. We propose a MDBMS, which has five layers. Attributes of elements in each layer as well as database operations are discussed. The system supports storage sharing and object reuse. The system is implemented on Windows ’98 with the support from a conventional database management system. Also, we present an instruction-on-demand system, which is an application of the underlying MDBMS. The instruction-on-demand system is used in the realization of several computer science-related courses in our university.

An Isochronous Approach to Multimedia Synchronization in Distributed Environments

In this chapter, we provide a new look at the synchronization issue in distributed environments. We attempt to explore the power of isochronous protocols, as advocated by Lamport, to the multimedia synchronization. It is based on the use of synchronized physical clock time instead of any form of logical clock or sequence numbers, and thus the clock synchronization across the distributed system is assumed. An isochronous protocol for achieving multimedia synchronization is presented. Derived from the globally synchronized clock, there exists a lattice structure in a system. Media conference participating processes in the system execute a simple clock-driven protocol, and all significant events (the sending and delivering of media data) are restricted to occur at lattice points of the globally synchronized space/time lattice. This lattice structure greatly simplifies the multimedia synchronization and readily maintains the temporal and causal relationship among the media. The basic simplicity of the approach makes it easier to understand the precise properties and behavior of a system. The availability of globally synchronized clock (for example, the new version of Internet NTP) and predictable quality of service of advanced communication networks make the isochronous synchronization approach not only attractive but also practical.

Network Dimensioning for MPEG-2 Video Communications Using ATM

This chapter discusses various issues related to the shaping of Motion Picture Experts Group (MPEG) video for generating constrained or controlled variable bit rate (VBR) data streams. MPEG-2 defines a set of standards for coding and compression of digital video. VBR video can offer constant picture quality without incorporating too much processing overhead in the network or transmission system’s architecture. In addition, they can offer substantial (20% to 50%) savings in both storage and transmission bandwidth requirements compared to constant bit rate (CBR) video. Either source coding or encoder’s output shaping or a combination of both can be used for adapting the MPEG-2 video streams for transmission over real-time VBR (rt-VBR)-type asynchronous transfer mode (ATM) channel.

QoS - Aware Digital Video Retrieval Application

Delivering high quality video content to customers is now expected to be one of the driving forces for the evolution of the Internet as it can be deployed in many niches of the emerging e-market. This chapter presents an originally developed Video Retrieval application with its unique features including a flexible user interface based on HTTP browser for content querying and browsing, support for both unicast and multicast addressing and a user-oriented control of QoS of video streaming in Integrated Services IP networks. The remaining part of the chapter is devoted to some selected methods of information systems’ modelling requested for the prediction of a system performance and an influence of different control mechanisms on quality of service perceived by end users.

VBR Traffic Shaping for Streaming of Multimedia Transmission

In multimedia applications, media data such as audio and video are transmitted from server to clients via network according to some transmission schedules. Different from the conventional data streams, end-to-end quality-of-service (QoS) is necessary for media transmission to provide jitter-free playback. Therefore, each data packet has been assigned with related timing constraints for transmission. As network resources are allocated exclusively in fixed-size chunks to serve different data streams, it is simple to support constant-bit-rate (CBR) transmission. Grossglauser and Keshav (1996) have investigated the performance of CBR traffic in a large-scale network with many connections and switches. They concluded that the network queuing delay for CBR transmission is less than one cell time per switch even under heavy loading. Besides, resource allocation and admission control are simple as there are no variations in resource requirements. However, media streams are notably variable-bit-rate (VBR) in nature due to the coding and compression technologies applied (Garrett and Willinger, 1994). The average data rate of an MPEG-1 movie is usually less than 25% of its peak data rate. It is inherently at odds with the goals of designing efficient real-time network transmission and admission control mechanisms capable of achieving high resource utilization (Sen et al., 1997). The conventional CBR service model that allocates the peak data rate to transmit the VBR stream would be a waste of bandwidth. Furthermore, it requires a large size of client buffer. To ameliorate this problem, we need a good traffic shaping algorithm to transmit VBR video in a less bursty (i.e., smoother) manner by exploiting different performance measurements. In a multimedia system, we usually measure the performance of a transmission schedule by the following four indices: peak bandwidth, network utilization, initial delay and client buffer.

Methods for Dealing with Dynamic Visual Data in Collaborative Applications - A Survey

Many important collaborative applications require the sharing of dynamic visual data that are generated from interactive 3D graphics or imaging programs within a multimedia environment. These applications demand extensive computational and communication costs that cannot be supported by current bandwidth. Thus, suitable techniques have to be devised to allow flexible sharing of dynamic visual data and activities in real time. This chapter first discusses important issues that need to be addressed from four perspectives: functionality, data, communication and scalability. Current approaches for dealing with these problems are then discussed, and pertinent issues for future research are identified.