This article is represent on Computer Network Overview System. In modern age Computer networking or data communication is a most important part of the information technology. Computer network use for smooth operations, flexibly, instant communication and data access. There are various kind topology of a computer network. A topology defines the physical layout or a design of a network. These topologies are star topology, bus topology, mesh topology, star bus topology etc. There are different standards and devices which is most commonly used standard for a local area network is Ethernet.