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IPTV technology on the existing transmission network, a higher load capacity requirements, including the physical load and the IP bearer. 1 Introduction IPTV or Internet TV, which combines Internet, multimedia and telecommunications and other technology, and use of broadband network infrastructure to home TV (or computer) as the main terminal through the IP protocol to provide TV programs to users within a variety of interactive digital media services and value-added services. IPTV The biggest advantage of "interaction" and "on-demand viewing," and completely changed the way traditional TV Broadcasting Features. According to device functions, a typical IPTV system can be divided into the media platform layer, Service layer, operational support layer, IP bearer layer and the terminal layer five. IPTV technology on the carrying capacity of existing transmission networks put forward higher requirements, including physical bearing and the IP bearer. IPTV system to hold the most important include Video on Demand (VideoonDemand, VOD) and TV Channel (Television) program. 2IPTV system load requirements IPTV is a real time Streaming Media Business, it end to end bandwidth, delay, jitter and bit error rate and so there are higher requirements. To ensure the quality and effectiveness of watch, IPTV bearer network system must be able to provide protection in the following areas. user access bandwidth. Using the MPEG-2 encoding time is not less than 3 ~ 4Mbit / s, using MPEG-4 or higher compression ratio of encoding time is not less than 2Mbit / s. channel switching delay. Cable television Channel switching is very fast network, IPTV end to end should be to minimize the delay. According to the survey, IPTV users within the receiving 1s TV channel switching time and VOD within 10s switching time. (3) IPTV Quality of Service (QoS). Packet loss and jitter, and this will seriously affect the viewing quality of IPTV, IPTV will make users feel as cable TV. 3IPTV system to hold technology IPTV Systems IPTV service bearer network is bearing the physical media, mainly by the access layer, the core layer (ie, special IPTV bearer network) and the convergence layer (other media, and multicast routing and switching equipment) form. In this paper, the existing Broadband Network based on the proposed IPTV system to hold some of the related technology. (1) access layer Access layer is the system the most critical link in the bearer network, which complete the user terminal, IPTV networks and service nodes, responsible for IPTV service access authentication of users, user-oriented multicast replication. IP-DSLAM Technology Taking into account the actual situation of the existing broadband network, it is recommended the use of copper in the IPTV system, access to programs that access technology based on ADSL2 +. In the IP-DSLAM in the exchange of data packets within the device and data aggregation are used Ethernet format and pure IP core, with sophisticated IP Multicast feature. Use IP-DSLAM access network technology of IPTV system structure shown in Figure 1. Present typical ADSL broadband access methods and LAN mainly two. ADSL Modem users access to the central office of the IP-DSLAM equipment, and then access switch, aggregation switches, broadband access server received (BRAS); LAN users through the corridor, switches, access switches and the aggregation switch receives BRAS. Access switch and aggregation switches support VLAN nested function QinQ (IEEE802.1Q-in-QVLANTag), the user business package to support unicast SVLAN (StackableVLAN) switch load, while multicast services only for transparent transmission. I am an expert from scrolltabletpc.com, while we provides the quality product, such as Wrist Watch Phone , Gsm Bugs Manufacturer, Quad Gsm Phone,and more.
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