Optical Packet Switching

Optical Packet Switching

INTRODUCTION:

Very high bandwidth in data communication is no longer a problem thanks to the recent advantages in optical networks. The main concern is how to utilize all the available bandwidth and how to achieve acceptable throughput. With packet switched networks transmission capacity can be utilized efficiently if the traffic load is mainly composed of asynchronous sources such as the data traffic. Typically electronics is used to carry out sophisticated processing, monitoring, and switching while optics is used is well developed for transmitting data. However, as the moderate advances in electrical switching has not kept up with the rapid development in optical transmission new approaches are required to handle switching at the routers. All optical packet switching fits this role if the technological obstacles can be overcome.
Generally, in digital networking system the message is broken into the small packets and these packets are sent to their destination and reassembled at destination again. And when this packet switching technique is implemented in the optical domain, termed as Optical packet switching. This Optical packet switching switches the packet in optical domain without optical-electrical-optical conversions.
An Optical packet network consists of optical packet switches interconnected with fibers running WDM.Each stream of information from source to destination is split into small packets, which are individually switched. This gives more flexibility than pure WDM approaches as virtually any kind of traffic, at any data rate can be carried. It is more efficient as the capacity is not continuously reserved for a connection but only when data is actually being transmitted. The packet comprises of a header and a payload. At each node the packet header is looked up in a look-up table, which decides the next hop of the packet. This header processing is in electronic domain with research going on to allow all optical processing. The payload is in optical domain only.


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