A computer network is a system in which multiple computers are connected to each other to share information and resources.
Characteristics of a Network:-A network is a group of systems that are connected to allow sharing of resources—such as files or printers—or sharing of services-such as an Internet connection .There are two aspects of setting up a network: the hardware used to connect the systems together and the software installed on the computers to allow them to communicate.
Basic Communication Model :-Communication model is used to exchange data between two parties. For example communication between a computer, server and telephone (through modem).
•Source- Data to be transmitted is generated by this device, example: telephones, personal computers etc.• Transmitter- The data generated by the source system are not directly transmitted in the form they are generated. The transmitter transforms and encodes the information in such a form to produce electromagnetic waves or signals.
• Transmission System- A transmission system can be a single transmission line or a complex network connecting source and destination.
• Receiver- Receiver accepts the signal from the transmission system and converts it to a form which is easily managed by the destination device.
• Destination-Destination receives the incoming data from the receiver.
Network Topology:-
Topology is the geometric arrangement of a computer system. Each computer system in a topology is known as a node.
Network topology is determined only by the configuration of connections between nodes.
• Bus Topology:- A bus topology is such that there is a single line to which all nodes are connected and the nodes connect only to this bus.
• Mesh Topology:- This type of network topology contains at least two nodes with two or more paths between them.
• Ring Topology:- In this network topology, every node has exactly two branches connected to it. The ring is broken and cannot work if one of the nodes on the ring fails.
• Star Topology:- In this network topology, the peripheral nodes are connected to a central node, which rebroadcasts all transmissions received from any peripheral node to all peripheral nodes on the network, including the originating node.
•Tree Topology:- This is a network topology in which nodes' are arranged as a tree. The function of the central node in this topology may be distributed.