Abstract:
The growth -of existing and new services will create a large increase of traffic flow in telecommunication network in the coming years .The demand for bandwidth in a communication network increase continuously .The world wide web alone ‘for example require a yearly 8 fold increase in bandwidth per user . All optical networks may be the only solution to cope with such increasing bandwidth .In these network transmitter signals remain in optical format on the way from source to destination

The wave length division multiplexing WDM technology offers a practical way to exploit the bandwidth of fiber optics by partitioning the optical bandwidth into separate channels .Photonic packet switching offers high speed ,data rate transparency ,and configurability which are some of the important characteristics needed in future networks supporting different forms of data

2. TYPES OF SWITCHING

There are three main types of switching:
1. Circuit switching
2. Packet switching
3. Cell switching

Circuit Switching :
This type of switching is the one used in the field of conventional telephony . In an end-to-end dedicated link is set up before communication starts. This link is solely used for this communication and after that it is broken .The steps involved in the process of circuit switching are
1. Circuit setup
2. The actual communication
3. Clearing of the circuit

Packet switching:
Here data is sent as packets .Due to this fact, there is an efficient utilization of the communication line. The earlier problem of waiting does not occur here as more than one source can use the line at the same time.