Switching

 Introduction 

Switching refers to the methods of data transmission between hosts through nodes. As data transmissions pass to each other they must travel through a network of nodes in the form of a data whole transmission or in segments called packets.

Circuit Switching

In circuit switching a designated path through the nodes is created and held for the duration of data transmission. Data is transmitted as a whole entity along the same route, this provides full bandwidth and ensures an uninterrupted connection to the network. This also causes inefficiency as a route may remain reserved even if no actual data is currently being transmitted. circuit switching is now being phased out for the more popular and faster packet switching methods so is now found only in older applications such as phone lines.

 Packet switching 

Packet switching separate data transmissions into several data chunks know as packages. Packages contain two parts the header which consists of data relating to its recipients location and restructuring, and the payload which hold the segment of the origination transmission which the packet is carrying. in packet switching the data may take different routes through the nodes in order to achieve a more efficient path by preventing congestion and allowing a nodes to remain open to other transmissions on the same network. this also allows for packet priority to be integrated as more important transmissions can be allowed access to the fastest routes while less important packet can be assigned to slower nodes. packet switching is less reliable than circuit switching as nor connection is guaranteed and faulty nodes may result in packet loss and corrupted data. packet switching is used on modern large scale application such as the internet and smaller networks.

Virtual Circuit

virtual circuit switching is one of two methods of data transmission on a packet switching network. In virtual circuit much like circuit switching an established route between nodes is formed however instead of a bulk transmission data is transmitted in the form of packets. This method is more reliable that datagram as packets arrive in the correct order and there is a much lower packet loss rate. however it is also slower as transmission speed is limited to the chosen route.

Datagram

In datagram data transmissions are sent in the form of packets and are treated as individual data transmissions. This means a faster transmission rate is achieved as some packet may find faster paths, this results in an end collection of packets in the incorrect order due to the differing speeds of the different nodes. There is a larger packet loss with datagram as the use of many nodes increases the failure rate, however this sacrifice results in much faster overall data transmissions.

- Alex Carolan