Multiobjective evolutionary approach to cost-effective traffic grooming in unidirectional SONET/WDM rings

Traffic grooming in optical networks is the process of multiplexing and demultiplexing low-speed traffic streams onto high-speed wavelengths. The research in the domain of traffic grooming mainly focuses on minimizing number of SONET add/drop multiplexers (SADMs) in SONET/WDM rings and it has been shown that they can potentially be reduced by careful assignment of low-speed traffic streams onto high-speed wavelengths. However, the cost of the network not only depends on the number of SADMs, but also the number of wavelengths and the grooming ratio. It is often the case that all of them cannot be minimized simultaneously. In this article, the problem of minimization of cost of a SONET/WDM unidirectional ring has been modeled as a multiobjective optimization problem which simultaneously minimizes the number of SADMs, the number of wavelengths, and the grooming ratio. A popular multiobjective genetic algorithm (NSGA-II) has been used as the underlying optimization tool. The resultant set of near-Pareto-optimal solutions contains a number of nondominated solutions, which the user can judge relatively and pick up the most promising one according to the problem requirements. Performance of the proposed algorithm has been demonstrated on different network topologies.

Combining GA with Splitting Methods for Rearrangeably Nonblocking Grooming of Dynamic Traffic in SONET Ring Networks

SONET/WDM rings are widely deployed in today’s networks. To reduce the total cost of such a network, an efficient way is using the traffic grooming technique to minimize the number of add/drop multiplexers (ADMs) on the ring. Since traffic often changes frequently, the problem of supporting dynamic traffic patterns with minimum number of ADMs and wavelengths becomes incresingly important, which is referred to as grooming of dynamic traffic. In this paper, we will deal with rearrangeably nonblocking grooming of arbitrary dynamic traffic in such ring networks. We will discuss in detail the benefit of splitting methods to such a grooming way and apply them to this kind of grooming. A novel genetic algorithm (GA) approach with a hierarchical chromosome structure for each individual is proposed in combination with splitting methods to address such grooming problems. Computer simulation results under different conditions show that our algorithm is efficient in reducing both the numbers of ADMs and wavelengths.     

MSF250的DS1/E1信号格式

MSF250是一个多业务成帧芯片。它带有DS1／E1接口，可将28个DS1或21个E1信号以位异步方式映射／解映射到VT．5／TU2路径中。文章从各种不同的帧格式和成帧原理论述了MSF250在DS1／E1映射／解映射中的应用方法。     

下一代网络技术:IP over DWDM浅谈

就当前IP传输发展的趋势，介绍了IP over DWDM技术的特点及其在上承载IP业务的几种解决方案。     

PDH,SDH／SONET技术及其应用（一）

本文论述了ＳＤＨ／ＳＯＮＥＴ技术产生和发展及应用，并从理论上对ＰＤＨＴ和ＳＤＨ／ＳＯＮＥＴ作了技术比较，此外，还介绍了ＳＤＨ传输网络结构和ＳＤＨ传送设备。     

新一代的因特网--光因特网

光因特网是新一代的因特网，是网络发展的重要动向。本文从为什么会提出光因特网着手，介绍了什么是光因特网，其网络结构和帧结构，还分析了光因特网的好处。     

智能光网络的技术及其发展

分析了网络业务对光网络发展的推动,智能光网络兴起之后,对智能光网络(10N)的关键技术进行了详细的分析和讨论,最后展望了智能光网络的发展前景。     

2.5Gb/s SDH/SONET传送开销处理器芯片实现

设计了一种2.5Gb/s同步光纤网络SDH/SONET中传送开销处理器芯片.采用双向4路总线流水线结构,77.76MHz的系统时钟,即可实时处理2.5Gb/s的SDH/SONET数据.支持STM-16、4路STM-4和STM-1的再生段开销和复用段开销处理以及STS-48、4路STS-12和STS-3的段开销和线路开销处理.采用TSMC 0.13μm工艺流片,电路规模约48万门,技术指标符合ITU-T标准.     

2.5Gb/s SDH/SONET指针处理器芯片实现

提出了一种2.5Gb/s同步光纤网络SDH/SONET中指针处理器芯片实现结构.指针处理器执行指针解释、通路开销性能监测功能,产生新的与系统时钟同步的STM/STS帧.指针解释模块对输入STM/STS通道的H1/H2指针进行解释,支持48通道的指针解释和每个通道的通路开销监测.采用4路总线流水线结构,77.76MHz的系统时钟,即可实时处理2.5Gb/s的SDH/SONET数据.采用TSMC 0.13μm工艺流片,技术指标符合ITU-T标准.     

分组环:城域网传输的未来技术

本文介绍了分组环网络,解释了它在城域网环境中的优越性,并且还提供了关于IEEE802.17 RPR标准的制定进展信息,IEEE 802.17 RPR工作组旨在开发弹性分组环的工业标准。