Computer Network Assignment A134334 & A135607

PlaceholderINTRODUCTION
Computer networking is a group of computer and devices interconnected by communications channels that allows users to share information and resources as hard drives, printers, scanners etc with each other.There are two types of network which is peer to peer and client/server.
 * A network refer as peer and peer networking if most computer are similar and run workstation operator.It typically has a mix of Microsoft Windows 9X, Me, Windows XP Homes Addition, or Windows XP Professional.In a peer-to-peer network, each computer holds its files and resources. Other computers can access these resources but a computer that has a particular resource must be turned on for other computers to access the resource it has.
 * A computer network is referred to as client/server if (at least) one of the computers is used to "serve" other computers referred to as "clients". Besides the computers, other types of devices can be part of the network.In a client/server environment, each computer still holds (or can still hold) its (or some) resources and files. Other computers can also access the resources stored in a computer, as in a peer-to-peer scenario. One of the particularities of a client/server network is that the files and resources are centralized. This means that a computer, the server, can hold them and other computers can access them. Since the server is always On, the client machines can access the files and resources without caring whether a certain computer is On.Another big advantage of a client/server network is that security is created, managed, and can highly get enforced. To access the network, a person, called a user must provide some credentials, including a username and a password. If the credentials are not valid, the user can be prevented from accessing the network.The client/server type of network also provides many other advantages such as centralized backup, Intranet capability, Internet monitoring, etc.In these series of lessons, the network we will build is based on Microsoft Windows operating systems.

BACKGROUND
The Advanced Research Projects Agency (ARPA) started funding the design of the Advanced Research Projects Agency Network (ARPANET) for the United States Department of Defense since 1960s. It was the first computer network in the world.Development of the network began in 1969, based on designs developed during the 1960s.Explosive Internet growth in the late 1990s dramatically affected the evolution of computer networking. Several inventions preceded the advent of computer networks, and paved the way for their eventual success. Alexander Graham Bell's telephone, demonstrated in 1876, provided the groundwork for networking connections, and Thomas Edison's work with electricity in the late 19th century gave us the structural framework for future computer technology.

BENEFITs
Computer network provide us a lot advantages.The advantages and benefits are:
 * 1) Facilitating communication. Using a network, people can communicate efficiently and easily via email, instant messaging, chat rooms, telephone, video telephone calls, and video conferencing.It had shorten the distance.
 * 2) Sharing hardware. In a networked environment, each computer on a network may access and use hardware resources on the network, such as printing a document on a shared network printer.
 * 3) Files, data, and information can be sharing efficiently. In a network environment, authorized user may access data and information stored on other computers on the network. The capability of providing access to data and information on shared storage devices is an important feature of many networks.People can send their files from one computer to another easily.Users can create files and store them in one computer then access those files from other computers connected to it.
 * 4) Sharing software. Users connected to a network may run application programs on remote computers.Users can run their programs which are not installed on their computers but are installed on any other user's computer.
 * 5) Save time.Users can done their works and search for the information that they want within a short time by just connecting the network.
 * 6) Save money.You can connect all the computers which are connected through a network to the internet by using a single line. So it means that you can save the connection cost for each computer but you internet connection must be fast.

WHAT IS NETWORK CLASSIFICATION
Connection method Wireless technologies Scale Functional relationship (network architecture) Network topology
 * Computer networks can be classified according to the hardware and software technology that is used to interconnect the individual devices in the network, such as optical fiber,wireless Lan,ethernet and etc.For example,Ethernet uses physical wiring to connect devices.Wireless LAN technology is designed to connect devices without wiring. These devices use infrared signals as a transmission medium.
 * Terrestrial microwave– Terrestrial microwaves use Earth-based transmitter and receiver. The equipment look similar to satellite dishes. Terrestrial microwaves use low-gigahertz range, which limits all communications to line-of-sight. Path between relay stations spaced approx, 30 miles apart. Microwave antennas are usually placed on top of buildings, towers, hills, and mountain peaks.
 * Communications satellites– The satellites use microwave radio as their telecommunications medium which are not deflected by the Earth's atmosphere. The satellites are stationed in space, typically 22,000 miles (for geosynchronous satellites) above the equator. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals.
 * Cellular and PCS systems– Use several radio communications technologies. The systems are divided to different geographic areas. Each area has a low-power transmitter or radio relay antenna device to relay calls from one area to the next area.
 * Wireless LANs– Wireless local area network use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area. An example of open-standards wireless radio-wave technology is IEEE.
 * Infrared communication, which can transmit signals between devices within small distances not more than 10 meters peer to peer or ( face to face ) without any body in the line of transmitting.
 * Networks are often classified as local area network (LAN), wide area network (WAN),metropolitan area network(MAN), personal area network (PAN), virtuall private network (VPN),campus area network (CAN), storage area network(SAN), and others, depending on their scale, scope and purpose.For example LANs tend to be designed for internal use by an organization's internal systems and employees in individual physical locations, such as a building, while WANs may connect physically separate parts of an organization and may include connections to third parties.
 * Computer networks may be classified according to the functional relationships which exist among the elements of the network,such as active networking, client server and peer to peer (workgroup) architecture.
 * Network topology is the coordination by which devices in the network are arranged in their logical relations to one another, independent of physical arrangement. Even if networked computers are physically placed in a linear arrangement and are connected to a hub, the network has a star topology, rather than a bus topology. In this regard the visual and operational characteristics of a network are distinct. Networks may be classified based on the method of data used to convey the data, these include digital and analog networks.

TWO TYPES OF NETWORKS BASED ON PHYSICAL SCOPE
Local area network Home area network
 * Local area network (LAN) is a network that connects over a relatively small geographical are, typically connecting computers within a single office or building. In most cases they connect to a common electronic connection- commonly known as a network backbone. LAN's can connect to other networks either directly or through a WAN or MAN.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.
 * Home area network (HAN) is a residential LAN which is used for communication between digital devices typically deployed in the home, usually a small number of personal computers and accessories, such as printers and mobile computing devices. An important function is the sharing of Internet access, often a broadband service through a CATV or Digitak subcriber line (DSL) provider. It can also be referred as an office area network (OAN).

BASIC HARDWARE COMPONENT
Computer hardware is the physical part of the computer including the digital circuits inside the computer as opposed to the software that carry out the computing instructions. The hardware of a computer is unlikely to change frequently unless due to the crash or for upgrading them. The devices that is capable of storing, executing system instructions and controlling other logical outputs.

Hardware comprises all of the physical part of the computer such as CPU,, ram, hard disk, network interface card and others.

The impotant component of hardware is Motherboard.Motherboard consists of CPU,Computer Fan,RAM,BIOS,Digital Circuitry,Computer Fan and PCI Slots.

CPU (Central Processing Unit)
CPU or central processing unit relates to a specific or processor.CPU chip (processor speed) determined the performance of computers and the other computer circuitry.The Pentium chip (processor) is the most popular chips available in the market today. The motherboard contains the hardware circuitry and connections that allow the different hardware components of the PC to interact and communicate with each other.

Hard Disk Drives
Disk drive is the mechanism to run the disks. All disks need a drive to get the information. Hard disk is used to store the data permanently.

Video cards
Video cards allow computer to display video, graphics and animation. Some video cards allow computers to display television.

Memory
Memory is the one of the important piece of the hardware. Sometimes memory chip memory is confused with the hard disk memory. Sometimes unallocated space of the hard disk is used as virtual memory also known as page file. This type of memory is a temporary memory and requires some additional memory to perform a specific task.

RAM (Random Access Memory)
RAM is a memory that is being used by the computer to store the information temporarily.the number of RAM affect the speed of computer works. Today at least requirement of a modern PC is 64 RAM. RAM is in the form of a chip and different vendors have developed the RAM of different capacities

Network interface cards
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.Repeaters are required for cable that runs longer than 100 meters. Repeaters work on the Physical Layer of the OSI model.

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.[7] It works on the Physical Layer of the OSI model.

Bridges
A network bridge connects multiple network segments at the data link layer (layer 2) of the OSI model. Bridges broadcast to all ports except the port on which the broadcast was received. Once the bridge associates a port and an have in three basic types:

1.Local bridges which is 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 datagrams (chunk of data communication) between ports (connected cables) 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. A switch normally has numerous ports, facilitating a star topology for devices, and cascading additional switches. Some switches are capable of routing based on Layer 3 addressing or additional logical levels; these are called multi-layer switches. The term switch is used loosely in marketing to encompass devices including routers and bridges, as well as devices that may distribute traffic on load or by application content (e.g., a Web URL identifier).

Routers
A router is an internetworking device that forwards packets between networks by processing information found in the datagram or packet (Internet protocol information from Layer 3 of the OSI Model). This information is processed in conjunction with the routing table (also known as forwarding table). Routers use routing tables to determine what interface to forward packets (this can include the "null" also known as the "black hole" interface because data can go into it, however, no further processing is done for said data).

CONCLUSION
In conclusion,computer network is so important to us especially in today's generation.It had makes our life easier and lighten up our future.Computer networks are collections of computers which are connected together in order to communicate and transfer information.The Native Computer Communications Network Project was a good example of how a focus on creating a network of computers does not necessarily ensure the interpersonal networking of the potential users of that technology. If the people were not communicating with each other before, developing another method of communication doesn't mean they'll start.