Abstract
Nowadays, with the evolution of digital video broadcasting, as well as, the advent of high speed broadband networks, a new era of TV services has emerged known as IPTV. IPTV is a system that exploits the high speed broadband networks to deliver TV services to the subscribers. From the service provider viewpoint, the challenge in IPTV systems is how to build delivery networks that exploits the resources efficiently and reduces the service cost, as well. However, designing such delivery networks are affected by many factors including choosing the suitable network architecture, load balancing, resources waste, and cost reduction. Furthermore, IPTV contents characteristics; particularly size, popularity, and interactivity play an important role in balancing the load and avoiding the resources waste for delivery networks. Ignoring the content status in solving delivery networks issues particularly replica placement, request distribution, and resource allocation problems leads to load imbalance, which in turn, leads to performance degradation in IPTV system. In this survey paper, we introduce IPTV delivery networks terminology and taxonomy. Upon that, we investigate the challenges related to the contents' awareness in those delivery networks. At the end of the paper, we propose a content-awareness in ITV delivery networks and CDN as the future direction and discuss its importance in different aspects as request redirection, resource allocation, and replica placement.