智慧协同网络分布式映射系统强一致性研究

发布时间：2018-04-25 10:25

本文选题：智慧协同网络 + 映射系统　；参考：《北京交通大学》2017年硕士论文

【摘要】：随着网络的迅猛发展,互联网原始设计的弊端日益体现。北京交通大学下一代互联网互联设备国家工程实验室提出了智慧协同网络模型,通过“三层”、“两域”的范围划分,将多种信息所携带的双重含义分离开,有效地解决了现有网络体系的问题。作为智慧协同网络的核心部分,映射系统将用户的身份信息与位置信息予以映射分离,并为映射关系条目提供了存储管理以及解析查询服务。在使用该网络通信时,接入交换路由器得到通信对端的映射关系后,会把该映射关系缓存至本地,以便再次使用时无需向服务器发起重复查询,从而减小时延。当通信对端映射关系发生改变时,接入交换路由器无法及时与服务器端同步,之前所缓存的映射条目便会过期失效,从而产生一致性问题。由于当前系统使用弱一致性机制,发送方会使用已过期的映射关系,该行为会使数据发往错误终端,导致通信过程受到影响。因此,映射系统中的一致性问题亟待解决。针对该问题,本文设计了一种适用于智慧协同网络分布式映射系统的强一致性方案。首先,对映射服务器与接入交换路由器之间的通信流程和交互模块进行重新设计,引入租约机制,通过在映射服务器与接入交换路由器之间建立租约关系,实现对映射条目租约的授予、维持与无效化,防止失效的映射关系被继续使用,达到映射系统的强一致性。然后,在服务器端,记录下使用过映射关系的接入交换路由器信息,当映射关系发生改变后,服务器会主动向相应的接入交换路由器列表通告其无效化。其次,在接入交换路由器端,对服务器返回的映射条目进行时长为租约期限的计时,当租约到期后,接入交换路由器若想使用该映射条目需向服务器端验证该条目的有效性;在收到服务器发送的无效通告后删除过期映射条目,从而有效保证了缓存的映射信息在失效后不会被再次使用。最后,根据以上设计思路,对映射系统相关模块进行编程实现。本文对上述方案进行了测试。功能测试结果表明,使用租约机制的映射系统能够防止过期的映射关系被继续使用,从而实现了映射系统的强一致性;性能测试结果表明,随着映射关系改变频率的降低或通信对端距离的减小,强一致性较弱一致性的性能提升会更显著。论文结尾对全文工作予以总结,并对后续工作进行了展望。
[Abstract]:With the rapid development of the network, the drawbacks of the original design of the Internet are increasingly reflected. The National Engineering Laboratory of next Generation Internet Interconnection equipment of Beijing Jiaotong University has put forward a intelligent cooperative network model, which separates the double meanings carried by various kinds of information by dividing the scope of "three layers" and "two domains". It effectively solves the problem of the existing network system. As the core of intelligent cooperative network, the mapping system separates the user's identity information from the location information, and provides storage management and parse query services for mapping relational items. When using the network communication, the access switching router will cache the mapping relation to the local area after obtaining the mapping relation of the communication end, so that the repeated query to the server is not necessary when used again, thus reducing the delay. When the communication to end mapping relationship changes, the access switch router can not synchronize with the server in time, and the previously cached mapping items will expire, resulting in consistency problem. Due to the weak consistency mechanism used in the current system, the sender will use the expired mapping relationship, which will cause the data to be sent to the wrong terminal, which will affect the communication process. Therefore, the consistency problem in the mapping system needs to be solved urgently. To solve this problem, this paper designs a strong consistency scheme for intelligent collaborative network distributed mapping system. Firstly, the communication flow and interaction module between the mapping server and the access switching router are redesigned, and the lease mechanism is introduced to establish the lease relationship between the mapping server and the access switching router. In order to achieve the strong consistency of the mapping system, the lease of mapping items is granted, maintained and invalidated, and the invalid mapping relationship is prevented from being used again. Then, on the server side, the information of the access switch router that used the mapping relation is recorded. When the mapping relation changes, the server will announce the invalidation to the corresponding list of access switch routers. Secondly, in the access switch router, the length of the mapping item returned by the server is the timing of the lease term. When the lease expires, the access switch router needs to verify the validity of the item to the server if it wants to use the mapping entry. After receiving an invalid notification from the server, the expired mapping entries are deleted, which effectively ensures that the cached mapping information will not be used again after failure. Finally, according to the above design ideas, the mapping system modules are programmed. The above scheme is tested in this paper. The functional test results show that the mapping system using the lease mechanism can prevent the expired mapping relationship from being used again, thus realizing the strong consistency of the mapping system, and the performance test results show that, With the decrease of the frequency of the mapping relationship or the decrease of the communication distance, the performance improvement of strong consistency is more significant than that of weak consistency. At the end of the paper, the paper summarizes the work of the paper, and looks forward to the follow-up work.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP393.0

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