【作者】 陈美燎；

【导师】 窦军；

【作者基本信息】 西南交通大学 ， 计算机应用技术， 2007， 硕士

【摘要】 Internet是上一世纪七十年代以文本数据传输为主的应用背景下诞生的网络，因此对正确性要求高，对实时性要求低。但随着多媒体网络应用数据流在Internet中的增加，使得Internet的“尽其所能”的服务难以满足新数据流的服务质量的需求，成为Internet面临的一大挑战。虽然Internet学界试图通过在IP层上增加服务质量保障技术，如资源预留协议、集成服务、区分服务，来改进Internet的服务质量。但现有的Internet的三层数据传输平台用户数据传输效率低，实施服务质量控制困难。针对现有网络体系结构在服务质量保障方面存在的不足，四川省网络通信技术重点实验室提出了“单物理层用户数据传输与交换平台体系结构”(SUPA - S ingle Physical layer User-data transfer & switching Platform Architecture)网络(SUPANET)。SUPA利用带外信令控制思想将用户数据传输平台(U平台)与信控、管理平台(S&M平台)相分离，而利用面向以太网的物理帧时槽交换(EPF7S - Ethernet-oriented Physical Frame Timeslot Switching)技术将用户数据传输与交换平台(U-platform)简化为单物理层结构，将服务质量保障机制嵌入该平台之中，直接保障用户数据交换的服务质量。SUPA在信控、管理平台支持服务质量协商、最少跳数(hop)的基于服务质量的波长路径选择(Shortest Path - Lambda QoS Rout ing，SP-LQR)、呼叫入网控制(CAC)一系列服务质量保障措施和策略，与用户平台的内嵌的服务质量保障机制，共同实现了SUPANET的服务质量保障。因为网络中的资源可能出现故障，所以为提高网络的可靠性SUPANET需要提供故障恢复能力。SUPANET的故障恢复机制是采用保护切换的方法，保护切换是一种可以在虚通路上的虚线路或节点出现故障时，使其上传输的业务流经过很小的中断后能快速的从故障中得到恢复的方法。在保护切换中，备份虚通路是故障发生之前预先建立的，当虚通路出现故障时，数据会被在切换点从失效了的虚通路切换到备份的虚通路上。SUPANET中基本的保护切换有四个步骤。首先，备份的虚通路必须在故障发生前事先建立。第二，SUPANET需要对故障进行检测。第三，检测到故障的节点必须向切换节点通知故障信息。第四，切换节点将业务流转发到备份虚通路上而不是原本的虚通路。在进行理论研究的同时，本文利用OPNET网络仿真软件对受保护的虚通路中的业务流进行了保护切换的仿真实验。建立了一个简化的SUPA网络模型，对切换处理过程中的数据丢失进行了仿真统计，仿真结果基本符合保护切换的特征，验证了保护方法的可行性。更多还原

【Abstract】 Internet was developed for text-oriented network applications in the 1970s, and it requests correctness of contest without real-time requirement. But with increase of multimedia application traffic in Internet, the "best effort" service provided by Internet does not able to satisfy users’ different QoS requirements and become one of challenges to Internet. Although the Internet communit attempts to improve the technology in the IP level to improve the quality of service, they are RSVP、Integrated Service、Differentiated Service and etc. But the low efficiency of the existing 3-layers user-data switching platform is difficult to insure the QoS of the service.To solve these problems, Sichuan Network Communication Technology Key Laboratory, Southwest Jiaotong University has defined a new network architecture called SUPA (Single physical layer User-data transfer & switching Platform Architecture). The SUPA simplifies User-data transfer & switching platform (U-platform) into a single physical layer platform by adopting the out-band signaling concept. The key technique enabling the single U-platform is called EPFTS (Ethernet-oriented Physical Frame Timeslot Switching),and guarantee the QoS of the data.SUPA has defined a set of mechanisms both in the S&M-platform and U-platform.In S&M-platform they are QoS Negotiation Protocol (QoSNP), QoS-based lambda Routing Information Protocol (λQoS RIP), Traffic Monitoring & Exchange Protocol (TMEP), Call Admission Control (CAC),and together with the mechanism in U-platform they guarantee the QoS of SUPANET(network supports SUPA). An important component of providing QoS, is the ability to do so reliability and efficiency. To make SUPANET reliable there is need for failure recovery mecasims in SUPANET. The failure recovery mecasim in SUPANET is Protection Switching, which is a method of ensuring recovery from link or node failure without disruption to the data traffic. In Protection Switching, the backup VP is pre-provisioned, when the pximary path is failed ,data traffice is switched from the failed VP to a backup VP.The basic protection switching consists of four steps. First, backup VP must be established. Second, the SUPANET must be able to detect the failure. Third, nodes that detect the failure must notify switching node in the SUPANET of the failure. Forth, instead of sending traffic on the primary VP switching node must send traffic on the backup VP instead.OPNET is used to simulate the protection in SUPANET to validate its availability and efficiency by constituting a simplified SUPA network topology structure while doing fundamental research. The relevant simulation results indicate the validity of protection in SUPA networks which basically complies with the feature of restoration procedure.更多还原