With rapid growth of broadband network deployment and multimedia streaming development, IP multicast networks soon become a delivery mechanism for real-time broadcasting television content. Unlike analog television broadcasting, IPTV is to provide two-way interactive service for viewers to access the selected program channel with high quality multimedia presentation and fast channel surfing capability. However, the traditional IP multicast network can not meet above requirements for IPTV between service provider and end users. To cope with this problem, we propose a hybrid mechanism, which combines the advantages of RP (rendezvous point) based shared tree (RPT) and specific source based shortest path tree (SPT) in traditional IP multicast protocol, called hybrid tree based explicit routed multicast (HT-ERM) approach for IPTV service. In particular, thanks to fast-join/leave/switch-over operations for IPTV channel switching and RSVP-TE (reservation protocol with traffic engineering) for explicit routed path setup, HT-ERM can satisfy QoS guarantee. With channel surfing mode, the low-bit-rate quality streams can be accessed by fast-join/leave through aggregated shared multicast tree. In contrast, the high-bit-rate quality stream can be served by fast switch-over to the specific source channel in watching mode. In our simulation, the proposed HT-ERM mechanism can achieve better performance than other QoS based multicast approaches, in terms of channel switching delay, resource utilization, and blocking ratio for IPTV service.
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