Understanding Communication Network Systems

At its simplest form, a communication network is a system of interconnected electronic devices that can send and receive messages to each other. Small networks can be linked together to form larger networks and can employ varied means of transmitting messages. The term is broad and can be used to refer to a small local or in-house computer network, the Internet (which is a world-wide network of networks) or even the old public switched telephone network.

Whatever form, type or function, all communication network systems have three basic elements. These are (1) terminals, (2) communication processors, and (3) communication channels. Terminals are where communication may begin and end. Any device used for input or output can be called a terminal. Communication processors are intermediate devices that help terminals receive and transmit messages. These devices provide support functions such as converting analog signals to digital, or decoding encrypted messages. Communication channels are the routes the transmitted messages travel. Communication network systems inevitably integrated computers and these machines installed with control software became a central component of most communication networks.

Electronic devices in a communication network are able to transmit and receive messages because they follow a standardized set of rules or conventions. These standard rules are called network protocols. Protocols define how network devices may identify, locate and connect with each other. They also include conventions on how messages should be formatted and transferred. Numerous protocols have been developed to perform specific functions within a network and work within particular settings. One broad set is called Internet protocol (IP) and under this large category are actually more specific protocols that function in tandem with IP. Hypertext transfer protocol (HTTP) for example defines request and response interactions of client and server computers. HTTP is a high-level protocol that works with computer software such as Web browser applications. Another set are called low-level protocols and these instead operate with computer hardware such as network adapters.

Computer networks follow a certain prescribed structure called the Open System Interconnection Reference Model or OSI Model. This model recommends that a network should have seven layers. A layer is a set of similar operations or functions. From the highest to the lowest level, these are: application, presentation, session, transport, network, data-link and physical. Each layer requests a service from the layer below it and provides a service to the layer above it.

The network layer is where message transfer procedures are enacted. It is at this layer that devices are able to identify and locate each other through the process called host addressing. Another significant process that occurs at this layer is called message forwarding. Most networks are divided into sub-networks and connect to other networks. Message forwarding ensures that data is transmitted successfully through the possible complex linkages of a network.

Communication network systems are not a simple subject that can be tackled in one sitting. It involves principles from electronic and communications engineering to computer science. The workings of the Internet and all the possible communication operations that can be done through it may seem quite arcane to some regular users. But they can acquire a deeper understanding of such matters through the numerous online resources that provide condensed and basic information and even networking tutorials that touch on the various aspects of the field.