High Efficiency Television Channel Transport On ASON

Automatically Switched Optical Networks(ASON) provides efficient, flexible and convenient service provisioning and network operation by constructing an intelligent control plane for optical equipments. It provides permanent connection, soft-permanent connection and switched connection. Multi-cast applications such as video conference, content distribution and interactive multi-media have stringent QoS requirements, and since optical multi-cast can ensure QoS, it is suitable for television channel transport. Television channel transport is an important profitable application of ASON. Multi-cast on ASON makes use of optical multi-cast instead of IP multi-cast in core networks, but encapsulate content in IP packets and still use IP switch at the access networks which makes this over-lay optical multi-cast compatible with traditional solutions. In the core networks, a single source connects several leaves with a multi-cast tree. Each tree node is configured with splitters and connected by point-to-multipoint connections. Though optical layer properties limits this configuration, such as node fan-out degree, signal power loss, wavelength conversion capability, it avoids O/E/O conversion and provides transparent signal path. It is suitable for high bandwidth, real-time data transport and it is an ideal multi-cast solution. The advantage of overlay of IP multi-cast and optical multi-cast is: a) It saves bandwidth by setting up multi-cast tree consist of optical multi-cast routers to substitute multiple point-to-point connections. b) It is compatible with traditional IP multi-cast in access networks since content is encapsulated inside IP packets. c) Circuit switching inside core network can improve QoS. However, television channel transport has new problem with this solution. Some of them is caused by television channel passes through switching capable networks while others are caused by ASON's control plane. This paper will primarily deal with high efficiency television channel transport on ASON.This paper discusses the following aspects: a) IP multi-cast makes use of group management protocol and multi-cast protocol to transport video stream for IPTV. End users join/leave multi-cast groups with group management protocol and television channel data flows through the multi-cast tree under control of multi-cast protocol. End users will experience channel zapping time caused by complex protocol processing. Service group...