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EE228a Project Proposal Issues in All-Optical IP Router Design Bo Wu, Fan Mo and Xuesong Jiang Over the past decade, the volume of data traffic transported across telecommunication networks has grown rapidly and the increase in traffic volume is forcing both incumbent and emerging service providers to design, build and add capacity to their networks. In order to satisfy the ever increasing demand for bandwidth brought about by the explosion of Internet, optical networks using wavelength-division multiplexing(WDM) are currently being deployed worldwide. It has been shown that the capacity of WDM is growing at a rate beyond Moore’s law and several Tb/s data transmission rate has been demonstrated in labs. The benefits of optical networking include: Large bandwidth. The bandwidth available in the low-attenuation passband within a standard single-mode optical fiber is 25THz. Multiple channels can be carried by a single fiber. More bandwidth can be requested and allocated dynamically by optical links. Easy Quality of Service(QoS) provisioning. In this project, we will address issues of all-optical IP router design in order to bridge the mismatch between the transmission capacities provided by the WDM layer and the processing power of IP router. We will focus on all-optical networking in which the transmission of data will not go through any optical-electrical conversions(Although the connections or light paths may be controlled by electronics). IP routers perform four main functions: routing, forwarding, switching and buffering. The major elements in an all-optical IP router include: A large optical switching fabric that provide the bandwidth management features and can be duplicated to provide high transmission availability. Transmission interfaces for connection to optical transmission facilities. A control structure that provide high control and maintenance availability. Primary non-volatile memory(NVM) and additional secondary NVM for robust software and database management. Currently, transmission and switching are executed in the optical domain, while routing and forwarding are carried out electrically, where the relatively complex packet header processing occurs independent of optical payload. This decoupling effectively permits the optical packet layer to support a range of networking protocols while attaining the power of WDM transmission. Nevertheless, in order to implement all-optical networking, optical packets should be routed in optical domain as well. Given that WDM allows cheap and easy incremental increases of the transmission bandwidth, frequent updates of the transport layer transmission capacity can be envisaged to match increased demand, which in turn placing heavy demands on the switching process. WDM optical packet switching shifts the bulk of the switching burden into the optical domain, permitting compatible scaling of the switching capability with WDM transmission capacity. The feasibilities and challenges in optical packet switching have been widely investigated in the last few years. Optical IP routers can be used as core routers in internet backbones. The inlets and outlets of a core router are optical fibers which operate in WDM mode with a number of wavelengths per fiber depending on the technology. More wavelengths per fiber could yield a higher degree of statistical multiplexing and lower blocking probability in the router. Nevertheless, problems such as all-optical synchronization, buffering, and node cascadability still need to be solved completely. The solutions available at the moment are far from field implementations. In order to effectively develop an IP router capable of providing a full optical data path at speeds approaching the limits of current electronic devices, namely 10 Gb/s and higher, a transfer mode has to be adopted robustly and efficiently enough to overcome technological limitations. Burst switching has been proposed as a possible solution, and it is well adopted in optical IP routing. However, processing of predominantly short IP packets becomes a problem at such high speed; therefore, it is necessary to introduce some lower limit on the granularity of switched data units in the backbone. A burst switching transfer mode paradigm has been proposed. Incoming packets are collected into bursts in the edge routers and sent through the backbone network where core routers will perform forwarding according to the destination in the burst switching. The core routers are supposed to exploit optical technology to reach a throughput on the order of multiple terabits per second and beyond. The various stages may be implemented by means of different technologies and with different architectures, but the basic functions to be performed are those described above. No optical-electrical conversion of data bursts is performed. This task is achieved by means of an all-optical switching matrix, for instance, based on the use of tunable wavelength converters and semiconductor optical amplifier space switches. Reference: [1]. S. Keshav and R. Sharma, “Issues and Trends in Router Design,” IEEE Communications Magazine, May 1998, pp. 144-51 [2]. D. Hunter and I Andonovic, “Approaches to Optical Internet Packet Switching,” IEEE Communications Magazine, September 2000, pp. 116-122