Studies On Key Technologies Of Converged Channel Bilateral Transmission In HFC Network

"Triple play" refers to the process of absorption, adaption and integration among the networks of telecommunication, cable TV and Internet, with the aim of establishing a uniform network of communication. Not only it will implement the integration and connection of current network resources, but also encourages novel services and operation mechanism, as well as the optimization of the information industry structure.Currently, with the advantages of interaction, Internet is competing for "Primary Media", which belongs to TV for many years. However, cable TV still only provides services mainly in unilateral transmission, in other words, in the traditional broadcasting way, which can not satisfy the customers."Triple play" is the inevitable trend of future network development. The opportunity of HFC network bilateral reconstruction, which is the necessarily choice of the development of cable TV network, will greatly promote the services of digital TV, broadband access and interactive TV, and finally increasing the competitive strength of cable TV network.In this articla, Converged Channel Gateway, or CCGW, is proposed as a transition scheme for HFC bilateral reconstruction according to the current demand for high-speed bilateral interactive services. Survey showed that, bilateral interactive services have the obvious characteristics of asymmetric transmission, which means the requirements is weak on uploading as well as strong on downloading. The CCGW make use of two different data transmission channels, which include the bilateral narrow-band IP channel and unilateral high-speed broadband HFC channel, to provide services of proxy and performance improvement, satisfy the customers'demand for high-speed interactive services, and improve the users'experience. Meanwhile, CCGW, which belongs to gateway devices logically, will face the challenge of a large amount of concurrent requests of data transmission, such as the packing and forwarding the data of high-resolution video clips. Such challenge will make great requirements on the processing capability of CCGW.This article first introduced the background of CCGW, included the concept of "Triple play" and HFC network bilateral reconstruction, followed by the introduction of the key technology involoved in the implement process of CCGW, which mainly included the tunnel packing technology, Netfilter kernel data package capture technology, Libpcap data package capture technology, Libnet data package sending technology, etc. This article breifly introduced the implement principle and calling method of such technologies. Finnaly, application coded in C++will be proposed to implement the mainly function of CCGW, which included the tunnel packing transmission, and the capture, convertion and transmission of data package.Finnaly, this article tested the performance of CCGW according to the original design. The result showed that CCGW did implement the function of converge two different data transmission channels for telecommunication, and the capability of data process is sufficient for practical application.