Study On Mechanism Of QoS Guarantee For CATV Broadband Integrated Service Network

CATV network has large excess bandwidth and high penetration to the home. The HFC broadband access system based on CATV network is becoming a main broadband access mode according with the situation of our country. With the fast development of modern network, communication and multimedia technologies, CATV network is evolving to a broadband integrated service network plant, and provides high speed transmission service of data, voice, image and video for residential subscribers. Broadband integrated services have special request to the transmission ability of network because of their special service property. Networks need adopting corresponding methods to control and guarantee the quality of these services. Quality of service (QoS) provided by the network for the broadband integrated services will determine whether the subscribers be satisfied or not and affect the growth of CATV broadband integrated service network. Traditional CATV networks only provided broadcasting TV program. Researches and experience on how to provide QoS guarantee for interactive multimedia broadband integrated services are comparatively lacking. Thus, study on the mechanism of QoS guarantee for CATV broadband integrated service network has important practical signification. It is also an important problem which must be solved in the CATV broadband integrated service network.In this dissertation, we gave a thorough study on the QoS architecture and mechanism of QoS guarantee for CATV broadband integrated service network, based on predecessor's researching results related to HFC broadband access system and network's QoS. And we proposed some advanced, reliable and applicable methods. The main contents and creative results of this paper are given as follows:(1) Giving some analysis and study on CATV network and its evolutionary trends. With the fast development of HFC broadband access and broadband IP network technology, modern CATV network is developing to a broadband integrated service network plant. We have a greatest CATV network in the world. Developing CATV broadband integrated service network is according with the situation of our country, and has practical signification and feasibility.(2) Giving a thorough research on mechanism of QoS guarantee for data service in CATV broadband integrated service network. TCP is the main protocol for controllingthe transmission of data service. We analyzed the traffic and congestion control of TCP, and how its performance and the QoS of data service are affected by the asymmetric character, upstream bandwidth allocation mechanism and upstream data transmission scheduling mechanism in the CATV broadband integrated service network. Methods to improve the QoS of data service in asymmetric networks are discussed. We proposed new upstream bandwidth allocation mechanism—Active Grant and upstream data transmission scheduling mechanism—Poll based on downstream data transmission rate. They improve the throughput and guarantee the QoS of data service in the CATV broadband integrated service network. The experimental results are showed in this paper and proved their function.(3) Giving deeply study on mechanism of QoS guarantee for real-time service in CATV broadband integrated service network. Based on analyzing the problem and limitation of proposed architecture and mechanism of QoS guarantee, we proposed a segment QoS architecture for the CATV broadband integrated service network, and improved the mechanism of reserving the network resource. The necessity of admission control to the broadband integrated service is discussed, and an admission control algorithm is proposed for the CATV broadband integrated service network.(4) Giving thoroughly research on the fault recovery ability of CATV broadband integrated service network. A mathematical model is built for the initialization ranging process of cable modem, while the network undergoing fault recovery. We emphasized on analyzing the average time of network completely recovering from fault. We proposed some methods to improve the faul...