Mpls-based Network Qos Mechanism

QoS is a comprehensive indicator, which is to measure the satisfaction when using a service. With the scale of Internet increasing and the emergence of many multi-media businesses, large amount of real-time businesses well up in IP network. Due to real-time businesses' sensitivity towards network's characteristics such as delay, delay jitter etc, and traditional IP network's incapability in some cases, IP network's failure to guarantee the specified QoS of the businesses has become the biggest obstacle of IP network's development into broadband comprehensive services network. How to meet the requirements of IP network's Qos to enable network to supply services according to businesses' characteristics is the most urgent problems in the network industry.To get rid of the limitations of IP network, experts have presented a lot of advanced technologies, among which Multi-protocol Label Switching-MPLS is the most superior tool that can ensure the network's QoS. MPLS supplies a connection oriented environment which facilitate the realization of QoS and traffic engineering in a connectionless environment caused by traditional IP network. In the MPLS forwarding paradigm, once a packet is assigned to a FEC, no further header analysis is done by subsequent routers; all forwarding is driven by the labels. This has a number of advantages over conventional network layer forwarding, including simplifying and acquiring higher speed, as well as achieving the function of constrained route, traffic engineering and VPN etc. As a successful combination of telecommunication network technology and computer network technology, MPLS has become a basic technology in realizing IP core network's QoS in the industry.This paper firstly introduces MPLS's basic theories, core technologies and working mechanism. Then it gives definitions and analysis on the models and parameters of IP network's QoS, and introduction on some prevalent basic models and technologies in realizing network's QoS. In the introduction the DiffServ, an improved method is proposed to alleviate the parameter dependence problem of random early detection (RED) algorithm. The main idea is to adaptively adjust the parameter according to the changed 'price' presented in the network traffic optimization theory. The new algorithm can rapidly adapt to the dynamic network situation and improve the capability of the network. In the main chapter, a new mechanism of QoS achievement in IPv6 network based on MPLS is proposed by using the traffic class field in IPv6 header According to the analysis of IPv6's QoS properties, DiffServ and MPLS. Following, According to the analysis of the rerouting model and the protection switching model for path recovery in MPLS, this paper proposes an efficient path recovery scheme inheriting the characters of the two models.The essay finally concludes the whole discourse and gives prospects for MPLS technology's application and development.