Summary

In recent years, IP-based video services have been developed rapidly in cable television (CATV) networks, especially the highly asymmetric IP-based services with large bandwidth, such as 4K, 8K and virtual reality (VR), whose single programme bandwidth might easily exceed 35 Mbps or even go up to 100 Mbps. This requires huge downlink bandwidth of transmission channels and poses challenges to the existing CATV technologies. For this scenario, it is necessary to propose a solution with lower cost and less complexity for meeting the bandwidth requirements of the current asymmetric IP-based video service.

Recommendation ITU-T J.1210 specifies an IP video broadcast (IPVB) technology, which simply adds a one-way IP-based video broadcast system to the existing low-cost bidirectional CATV networks, including both hybrid fibre coax (HFC) and optical networks. The IPVB can greatly increase the bandwidth of downlink programs when using an optical network and at the same time, have the characteristics of low cost and low complexity. The IPVB in downlink transmits IP-based video streams through broadcast channels which are identified by multicast IP addresses and user datagram protocol (UDP) port numbers and broadcasts all the IP-based video streams through the CATV networks to all subscribers. By cooperating with the uplink channel provided by the existing bidirectional access networks, it is capable of providing varieties of IP-based high bitrate video services in CATV networks.