基于城域网的NAT444资源池的优化方案研究

发布时间：2019-05-23 01:22

【摘要】：如今网络应用越来越多,与之相伴的网络地址的使用越来越匮乏,这一问题已经成为制约网络发展的一个很重要的因素。IPv6可以从根本上解决地址空间问题,但是目前很多网络设备和网络应用都是基于IPv4的,马上转移到IPv6网络是不现实的,因此网络在很长的时间将会处在由IPv4网络向IPv6网络的过渡中。对网络地址转换(Network Address Translation,NAT)过渡技术研究可以缩短向IPv6网络过渡的时期,而为了应对IP地址缺乏的问题,NAT444过渡技术应运而生。NAT444是运营商网络部署NAT的整体解决方案,它基于NAT444网关(即Carrier-Grade NAT,CGN)并与日志服务器、AAA服务器等网络应用系统配套使用,从而给运营商提供运营商级别的NAT服务。不仅如此,NAT444过渡技术因其端口块分配的方式可以支持用户溯源功能,因此,它目前已成为运营商首选的IPv6过渡方案。NAT444过渡技术性能的提高依赖于其资源池的合理配置,因此如何优化NAT444资源池成为业界研究的主要内容。为了优化NAT444资源池的性能,本文首次将优化后的hash算法,即JHash_3words算法应用到NAT444模块的资源池,克服了原来的bitmap算法无法对存在重复的数据进行排序和查找的不足,成功解决了无限连接冲突检测问题。此外,为了实现多核并发,本文首次基于原子操作对bitmap算法做了相应的改进,解决了原有算法单线程工作的弊端,使得NAT444设备可以进行多线程工作。本文在杭州华三通信有限公司型号为F5020集中式设备上进行NAT444资源池核心算法优化前后的性能测试。得到的结果表明,相比优化之前,NAT444设备无一报文丢失,网络地址端口转换的成功率为100%,解决了未优化前设备丢包这个致命的问题;CPU占用率有了明显的下降,新建性能得到了一定的提高。因此本文的改进对于NAT444资源池性能的优化是有明显的效果和意义的。
[Abstract]:Nowadays, there are more and more network applications, and the use of network addresses is becoming more and more scarce. This problem has become a very important factor restricting the development of the network. IPv6 can fundamentally solve the address space problem. However, at present, many network devices and network applications are based on IPv4, so it is unrealistic to transfer to IPv6 network immediately, so the network will be in the transition from IPv4 network to IPv6 network for a long time. The research on (Network Address Translation,NAT (Network address Translation) transition technology can shorten the transition period to IPv6 network, and in order to deal with the lack of IP address, NAT444 transition technology emerges as the times require. Nat 444 is the overall solution for operators to deploy NAT. It is based on NAT444 gateway (that is, Carrier-Grade NAT,CGN) and is used in conjunction with log server, AAA server and other network application systems, thus providing operators with operator-level NAT services. Not only that, NAT444 transition technology can support user traceability because of its port block allocation, so it has become the preferred IPv6 transition scheme for operators. The performance improvement of NAT444 transition technology depends on the reasonable configuration of its resource pool. Therefore, how to optimize NAT444 resource pool has become the main content of industry research. In order to optimize the performance of NAT444 resource pool, the optimized hash algorithm, that is, JHash_3words algorithm, is applied to the resource pool of NAT444 module for the first time, which overcomes the deficiency that the original bitmap algorithm can not sort and find duplicate data. The problem of infinite connection conflict detection is solved successfully. In addition, in order to realize multi-core concurrency, this paper improves the bitmap algorithm for the first time based on atomic operation, solves the disadvantage of the original algorithm single thread work, and makes the NAT444 device can carry on the multi-thread work. In this paper, the performance of NAT444 resource pool core algorithm is tested on Hangzhou Huasan Communication Co., Ltd. F5020 centralized equipment. The results show that compared with before optimization, none of the NAT444 devices are lost, and the success rate of network address port translation is 100%, which solves the fatal problem of device packet loss before optimization. The occupation rate of CPU has been obviously decreased, and the new performance has been improved to a certain extent. Therefore, the improvement of this paper has obvious effect and significance for the optimization of NAT444 resource pool performance.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP393.1

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