Abstract: Content delivery network (CDN) is a comprehensive, end- to-end solution for optimizing global networks for Web content delivery. Users requesting information from a Web site may have those requests served from a location closer to them than the original server on which it is generated. By serving content from points a lot closer to the user, a CDN reduces the likelihood of hot spots by dispersing the different points of convergence and by distributing the workload among multiple servers. Delivering content from the edge of the network instead of the original server has the added benefit of additional reliability. The probability of the lost packets is decreased, while the performance of streaming audio and video is improved.
CDNs deploy servers in multiple geographically diverse locations in order to redirect users requests to the nearest available servers. End users observe higher QoS, while content providers offer more reliable and larger volumes of the service. At the same time, Internet service providers (ISPs) can also benefit from deploying CDN servers in their networks, as the total amount of the traffic transmitted in the backbone is reduced. In order to address the issue faced by many content providers, companies started to provide a service called content distribution network service. Content distribution network is a "shared" infrastructure in that the mirror servers (also called replica servers) belonging to a network service provider are usually "shared" between multiple content providers. The value provided by the network service providers is measured by the amount of content downloaded from the major servers and the peak bandwidth needed to serve the content from the mirror servers. One of the main challenges for providers is to be able to find the "nearest" mirror server corresponding to a client. Typically, the IP address of the client is used to identify the location of the client.
This plenary speech is organized as follows. After the introduction, showing the current status in the area, the next section will describe the evolution of content delivery technologies, together with content delivery network functions. The fact that the content delivery technique offers the service of large scale based on IP networks is taken into account. In order to satisfy QoS requirements for heterogeneous Internet applications, system performances are improved. The second part deals with potential solutions to problems in IP networks. The emerging applications require varying amounts of reliability, functionality, speed, efficiency, cost, effectiveness and scalability. Therefore, it is necessary to bridge the gap between the emerging heterogeneous applications with various demands of service capacity and IP networks. The emerging challenges are server placement and organization, content distribution, request routing and system management. Several approaches are opened for consideration like: efficient streaming in future Internet, end-to-end multimedia communications across complex combinations of networks, peer-to-peer hybrid or fully distributed networking for content handling, content adaptation to facilitate content capabilities, etc.

Brief Biography of the Speaker:
Prof. dr Zoran Bojkovic is full professor of Electrical Engineering, University of Belgrade, Serbia. Also, he is a permanent visiting professor at the University of Texas at Arlington, TX, USA, EE Department. Until now, he has taught a number of courses in Electrical Technology, Telecommunication Systems, Image and Video Processing, Multimedia Wire/Wireless Communication Systems. He is the author or co-author of 6 international books published in USA, Canada, Singapore, China, India, Greece and Romania. Also, he has published 2 national monographies, 13 textbooks as well as more than 400 papers in peer-reviewed journals and conference proceedings. He has been Editor-in-Chief in 2 and Associate Editor in 3 WSEAS Journals. At present, he is a member of Editorial Board in 6 International Journals. He is co-editor in 51 International Books and International Conference Proceedings. He has conducted workshops/tutorials and seminars worldwide and participated in more than 70 research and industrial projects all over the world. Also, he has been a consultant to industry, research institutes and academia. Prof. Bojkovic is an active researcher in wire/wireless multimedia communications. He is a Senior Member of IEEE and WSEAS member of EURASIP. He is a full member of Engineering Academy of Serbia and a member of Serbian Scientific Society.