The problem of routing and wavelength assignment (RWA) in WDM (wavelength division multiplexing ) networks is addressed in this paper. Most of the attention has been devoted to RWA algorithm. In this article, some concepts on RWA are studied first. Then we studied the associated research problems and challenges on RWA. Various RWA approaches are examined and compared. Finally, we proposed a new RWA algorithm based on multi-objective. In this new algorithm, we consider multiple network optimizing objectives to setup a lightpath with maximize profit and shortest path under the limited resources. By comparing and analyzing, the proposed algorithm is much better than the algorithms, which only consider one optimizing objective. This new RWA algorithm may be useful to a network maker.
WDM ring network is gaining acceptance as its flexibility, simple management and well survivability. This paper looks at several kinds of WDM ring protection networks and some problems, which we must pay attention to, and then analysis and compares their performance. Finally, we give some principles of design the WDM ring protection networks.
With the development of transport networks, it must face many new challenges for the increased network survivability. In this paper, we analyses the problems of coordination between the individual layers recovery mechanisms. Based on the comparing of present three coordination methods, we propose a new coordination method, that is ¡° recovery ratio platform¡± method. This method can efficiently increase the restoration ratio and decrease the restoration time.
The more and more telecommunication networks are constructed with multi-techniques. This paper looks at several aspects of survivability ATM over SDH networks. Considered the specialty of ATM over SDH networks architecture, and focused on meshed networks, we proposes a new ATM over SDH network survivability scheme based on failures for the multi-layer networks: using failure-case-oriented restoration/protection implementations in order to meet the demands for the survivability of networks.
The SDH network self-healing mechanism is a very important content in research of SDH networks survivability and is also key to ensure network reliability. Based on the analyzing of traditional SDH self-healing ring, we proposed a new four fibers bi-directional intelligent path protection self-healing ring (BSHR/4IP) mechanism. By computer simulation, we estimate the performance of the proposed mechanism and prove that it has a high performance at restoration time, restoration ratio, utilization and complexity.
Because of the economic and technical advantages, laser processing technology has been developed rapidly in recent years. Jilin Province Laser Institute laser processing center set up a laser cutting production line, a laser heat- treatment production line, and a laser marking machine. In this paper we describe applied examples of laser cut, laser heat-treatment and laser marking.
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