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NETWORK KOMPUTER

Computer network is a system consisting of computers and other network devices such as cables, switch, hub, router, etc. working together to achieve a common goal. The purpose of the computer network are: – Sharing resources functions such as shared use of printers, CPU, RAM, hard drive – Communication: eg electronic mail, instant messaging, chat – Access to information: for example web browsing In order to achieve the same goal, each part of the computer network and provide service request (service). Party requesting the service is called a client (client) and that provide services called the servant (the server). This architecture is called client-server systems, and is used in almost all computer network applications. As for the classification of computer network based on the scale include: – Personal Area Network (PAN) – Campus Area Network (CAN) – Local Area Network (LAN) – Metropolitant Area Network (MAN) – Wide Area Network (WAN) – Global Area Network (GAN) Based on the function: Basically every computer network is functioning as a client and server. But there is a network that has a dedicated computer as a server and the other as a client. There is also a computer that has no special function as a server only. Therefore, based on their function there are two types of computer networks: • Client-server Network is the computer with a dedicated computer as a server. A service / service can be provided by a computer or more. An example is a domain like http://www.detik.com lots served by the web server computer. Or it could be a lot of service / services provided by a single computer. Examples are jtk.polban.ac.id server that is a multi-service computer with the mail servers, web servers, file servers, database servers and others. • Peer-to-peer Namely computer networks where each host can be a server and also a client simultaneously. For example in the file sharing between computers on the Windows Network Neighborhood Network have 5 computers (we give the name of A, B, C, D and E) that provide access rights to the files they have. At one point A to access the file share of B named data_nilai.xls and also gives access to the file soal_uas.doc C. When accessing a file from B then A serves as a client and as a give file access to C then A serves as a server. Both functions were performed by the same A network like this is called peer to peer. In some computer network topology applied in their construction. Other Anatara: star topology, topology BUS, Mesh topology, tree topology (tree), and Linear topology. In the topology of the above there are some advantages and disadvantages. Here uarain of computer network topologies mentioned above are: 1. Star topology is a form of network topologies in the form of convergence of the middle node to every node or user. Star network topology including network topology with high costs. The advantages of this network is: – Damage to one channel will affect only the channel network and the station adrift. – Including high-level security. – Resistant to traffic of a busy network. – Addition and subtraction station can be done easily. Disadvantages: – If the node was damaged, the whole network is interrupted. 2. Ring topology is a network topology point-shaped circuit, each of which is connected to two other points, thus forming a circular path to form a ring. In this topology, data communication can be disrupted if a single point impaired. FDDI networks anticipate this weakness by sending data clockwise and counterclockwise at the same time. 3. Bus topology On the bus topology, the network unjung must end with a terminator. Barrel connector can be used to expand it. This network consists of only one cable channel using BNC cables. Computers that want to connect to the network can be linked himself with all mentap Ethernet cable. Linear Bus: This layout includes the general layout. One main cable connects each node, to a single channel to access the computer with the tip end. Each node is connected to two other nodes, except the engine at one end of the cable, each of which is connected only to one other node. This topology is often found in the system client / server, where one machine on the network functioned as a file server, which means that the machine is devoted only to the distribution of data and is usually not used for processing information. Bus network installation is very simple, inexpensive and a maximum of 5-7 computers. The difficulty often faced is the possibility of data collisions because the mechanism is relatively simple network and if one node or having trouble off it will interfere with the performance and traffic throughout the network. – Excellence is the development of bus topology network or adding new workstations can be done easily without disrupting the other workstations. – Losses, fault detection and isolation is very small, high traffic density, lack of data security is assured, the speed will decrease when the number of users increases, and is required for long-distance Repeater Linear bus topology is a topology widely used in the use of Coaxial cable. By using the T-Connector (with a 50ohm terminator on the end of the network), then the computer or other network devices can be easily connected to each other. The main difficulty of using coaxial cables is difficult to measure whether the coaxial cable that is used completely matching or not. Because if you do not really measured correctly will damage the NIC (network interface card) that is used and the network performance becomes constrained, not reaching maximum capacity. This topology is also frequently used on networks with fiber optic base (which later merged with a star topology to connect with the client or node). Type connector for the BUS network consists of 1. BNC cable connector —> To connect the cable to the T connector. 2. BNC T connector —> To connect the cable to the computer. 3. Barrel BNC connector —> To connect 2 BNC cables. 4. BNC Terminators —> To mark the end of the bus topology. 4 nets or mesh topology is a kind of network topologies that implement full antarsentral relationships. The number of channels should be provided to establish this network is a central number minus 1 (n-1, n = number of central). The level of network complexity is proportional to the increased number of centrally installed. This topology is less economical but also relatively expensive in operation. Tree Network Topology 5 (tree) network topology is referred to as multilevel network topology. This topology is usually used for interconnection between different central denganhirarki. For the lower hierarchy depicted in the lower location and the top has a higher hierarchy. This type of network topology suitable for computer network systems. In tree networks, there are several levels of nodes (node). Center or a higher node level, another node can set a lower level. Data that is sent to the central node first. For example to move from computer to kekomputer node-node 3-7 as well as in the figure, the data must pass through node 3, node-5 and 6 before ending at node 7. Network Keungguluan tree model like this is, can the formation of a group that needed at any time. For example, companies can form a group consisting of terminal accounts, as well as on other groups formed for the sale terminals. The weakness is, if the node is higher then does not work, then another group who are below it eventually also became ineffective. How a tree network is slow relative to

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