Computer Network Assignment A134609 & A134568

Computer Network

Computer network can be defined as the connection between two or more computer devices. It provides connectivity to a group of computer systems and enables communication and resources sharing between them.

Introduction
A computer network allows sharing of resources and information among interconnected devices. In the 1960s, the Advanced Research Projects Agency (ARPA) started funding the design of the Advanced Research Projects Agency Network (ARPANET) for the United States Department of Defence Background and it became the first computer network.

Background
Before the advent of computer networks that were based upon some type of telecommunication system, communication between calculation machines and early computers was performed by human users by carrying instructions between them. Many of the social behaviors seen in today's Internet were demonstrably present in the nineteenth century and arguably in even earlier networks using visual signals.

Computer networks and the technologies needed to connect and communicate through and between them, continue to drive computer hardware, software, and peripherals industries. This expansion is mirrored by growth in the numbers and types of users of networks from the researcher to the home user.

Benefits
1. File Sharing

2. Printer / Peripheral Sharing

3. Internet Connection Sharing

4. Multi-Player Games

5. Internet Telephone Service

6. Home Entertainment

What is network classification?
Network classification is the ways in differentiate the networks type from their categories.

Connection method
Computer networks can be classified according to the hardware and software technology that is used to interconnect the individual devices in the network. Ethernet uses physical wiring to connect devices. Frequently deployed devices include hubs, switches, bridges, or routers. Wireless LAN technology is designed to connect devices without wiring.

Wired technologies

 * Twisted pair
 * Coaxial cable
 * Optical fiber
 * Wireless technologies
 * Terrestrial microwave
 * Communications
 * Cellular and PCS systems
 * Wireless LANs
 * Infrared communication

Scale

 * Local area network (LAN)
 * Wide area network (WAN)
 * Metropolitan area network (MAN)
 * Personal area network (PAN)
 * Virtual private network (VPN)
 * Campus area network (CAN)
 * Storage area network (SAN)

Functional relationship (network architecture)
Computer networks may be classified according to the functional relationships which exist among the elements of the network, e.g., active networking, client–server and peer-to-peer(workgroup) architecture.

Network topology
Network topology is the coordination by which devices in the network are arranged in their logical relations to one another, independent of physical arrangement.
 * Bus network
 * Star network
 * Ring network
 * Mesh network

Two types of computer networks based on physical scope
Type of networks is usually determined based on their scale.

Local Area Network
A local area network (LAN) is a network that connects computers and devices in a limited geographical area. Each computer or device on the network is a node, connected by Ethernet technology. All interconnected devices must understand the network layer, because they are handling multiple subnets. The defining characteristics of LANs, in contrast to WANs (Wide Area Networks), include their higher data transfer rates, smaller geographic range, and no need for leased telecommunication lines.

Wide Area Network
A wide area network (WAN) is a computer network that covers a large geographic area, using a communications channel that combines many types of media such as telephone lines, cables, and air waves. A WAN often uses transmission facilities provided by common carriers. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.

Basic hardware components

 * Network interface card

A network card, network adapter, or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network. It provides physical access to a networking medium and often provides a low-level addressing system through the use of MAC addresses.


 * Repeaters

A repeater is an electronic device that receives a signal, cleans it of unnecessary noise, regenerates it, and retransmits it at a higher power level, or to the other side of an obstruction, so that the signal can cover longer distances without degradation.


 * Hubs

A network hub contains multiple ports. When a packet arrives at one port, it is copied unmodified to all ports of the hub for transmission. The destination address in the frame is not changed to a broadcast address. It works on the Physical Layer of the OSI model.


 * Bridges

Bridges come in three basic types: (1) Local bridges: Directly connect local area networks (LANs), (2) Remote bridges: Can be used to create a wide area network (WAN) link between LANs. Remote bridges, where the connecting link is slower than the end networks, largely have been replaced with routers, (3) Wireless bridges: Can be used to join LANs or connect remote stations to LANs.


 * Switches

A network switch is a device that forwards and filters OSI layer 2 datagram between ports based on the MAC addresses in the packets. A switch is distinct from a hub in that it only forwards the frames to the ports involved in the communication rather than all ports connected. A switch breaks the collision domain but represents itself as a broadcast domain. Switches make forwarding decisions of frames on the basis of MAC addresses.


 * Routers

A router is an internetworking device that forwards packets between networks by processing information found in the datagram or packet. In many situations, this information is processed in conjunction with the routing table. Routers use routing tables to determine what interface to forward packets.

Conclusion
Networking is one of the most important component in information technology. it serves as the main connector between different parties around the world. the technology of networking is growing faster and faster to meet user demands of faster, and more efficient data transfer in order to ease everything else related.