A computer network includes, the network operating system in the client and server machines, the cables, which connect different computers and all supporting hardware in between such as bridges, routers and switches. In wireless system, antennas and towers are also part of the network.
Types of Computer Network
- Local Area Network (LAN):- In LAN, computers are connected locally within a room, building or in a small area. A LAN can range from simple (two computers) to complex (hundred of computers and peripherals). LANs connect workstations and personal computers. User can share data as well as devices like printers, fax etc and can use LAN to communicate with each other, by sending e-mail or chatting.
Characteristics of LAN are:
- Configured to small area i.e it connects several devices over a distance of 5 to 10 KM.
- High Speed.
- Low error rates
- Data and hardware sharing between user
- Operates at speed ranging from 10Mbps to 100 Mbps. Now a days 1000Mbps are available
- Bus topology:- In bus topology, all devices are connected to a central cable, called the bus or backbone. The bus topology connects workstations using a single cable. Each workstation is connect to the next workstation in a point to point fashion. All workstation connect to the same cable. An extension to the bus topology is tree topology.
- Ring topology:- In ring topology, all devices are connected to one another in the shape of a closed loop, so that each device is connected directly to each other i.e the ring topology connects workstations in a closed loop. Data is transmitted around the ring in one direction only. Each station passing on the data to the next station till it reaches its destination. The common implementation of this topology is token ring.
- Star Topology:- Star topology uses a central hub through which, all components are connected. A central hub is the host computer and at the end of each connection is a terminal. Communication on the connecting links between the stations and the central station of star topology can be bi-directional and are point to point.
- Tree topology:- Tree topology is LAN topology in which only one route exists between any two node on the network. It is similar to the star topology but the nodes are connected to the secondary hub, which in turn is connected to the central hub.
- Mesh topology:- Devices are connected with many redundant interconnections between network nodes. In a well connected topology, every node has a connection to every other node in the network. Mesh topology are used in critical connection of host computers (typically telephone exchange). Alternate path allow each computer to balance the load to other computer systems in the network by using more than one connection path available.