ZTE IPTV Data Bearer Network Solutions

IPTV on-demand service would typically adopt IP unicast technology for transmission, while IPTV direct-broadcast service would adopt IP multicast technology. Therefore, video service network are usually categorized into two types, namely, the on-demand service network and the direct-broadcast service network. These two types of video service networks have different technical requirements and require different technical features on the bearer network.

Generally, as the current network does not support the multicast technology, it is technically difficult in implementing multicast throughout the bearer network. In this case, it is recommended to implement the IPTV service quickly using the current features of the existing network, thus minimizing investment:

If the current network has enough bandwidth, but does not support multicast, the bearer networking plan can make no change on the current network by constructing a direct-broadcast transmission network for the direct-broadcast service according to the transmission resources, or using direct-broadcast trunks.

The VoD distribution network would still use the current network as the bearer, while the direct-broadcast video service is transmitted through the direct-broadcast transmission network. In this way, the direct-broadcast transmission network is physically separated from the Internet access network and the VoD distribution network, and their downlinks are combined on the BRAS or the DSLAM. As the direct-broadcast video service is transmitted through the multicast technology, and its flow in the transmission network is related to the number and contents of the channels only and stays unchanged when the user´s operation changes, the transmission network constructed facilitates network planning and construction. And a small-scale direct-broadcast transmission network can be constructed according to the actual requirement to decrease the cost. The schematic diagram of this solution is shown in Figure 1.

Figure 1 Bearer Network Solution in Case of Enough Bandwidth of the Current Network Which Does Not Support Multicast (1)

In this solution:

• The direct-broadcast video service enters the independent direct-broadcast transmission network from the video source. The direct-broadcast transmission network can be a unidirectional multicast network, which takes charge of multicast data report transmission only. It transfers the direct-broadcast video service to the access network.
• The original network bears the VoD service. According to the strategies, it stores, distributes, and unicasts the contents to the edge streaming server, which is next to the user and transfers the contents to the user through the access network.
• The Internet service is connected to the Internet through the broadband network.

The networking mode of the direct-broadcast transmission network varies with the equipment. It includes the router networking, layer-3 switch networking, and MSTP multicast. Carriers can select the proper networking plan according to their actual requirements.

Direct-broadcast trunk bearer

Different from constructing a direct-broadcast transmission network, the direct-broadcast trunk function supported by the IPTV service system makes the bearer network of the video service distribution network provide unicast support only when the bearer network does not support multicast. In the video service distribution network, the unicast mode is adopted to transmit the direct-broadcast service from the IPTV central server to the edge server of the IPTV system. Then, starting from the edge server, the direct-broadcast traffic is distributed to the IPTV broadband access network through the multicast mode. The schematic diagram of this solution is shown in Figure 2.

Figure 2 Bearer Network Solution in Case of Enough Bandwidth of the Current Network Which Does Not Support Multicast (2)