Topology Computer Networks

Topology describes the structure of a network or how a network is designed. This pattern is closely associated with access and media delivery methods are used. Topology that is very dependent on the location geofrapis of each terminal, the quality control needed in the communication or delivery of messages, as well as the speed of data transmission. In the definition of topology is divided into two, namely the physical topology (physical topology) which indicates the position of the physical cabling and logical topology (logical topology) which shows how the media is accessed by the host.

The physical topology is commonly used in building a network are:

   1.  Point to Point (Point to-Point).

    Networks point to a network of simplest but can be widely used. This network is so simple, so it is often not considered as a network but only an ordinary communication. In this case, the node has a level position, so that any node can initiate and control relationships within the network. Data sent from one node directly other conclusion as the recipient, for example between the terminal with the CPU.

    2. Star Network (the Network Stars).
    

 In a star configuration, some existing equipment will be connected into a central computer. Existing controls will be concentrated at one point, such as organize workload and resources of existing arrangements. All links must be related to the data center if you want to channel the other conclusions of the field. In this case, when the center was down, then all the terminals will also be disrupted. Star network model is relatively simple, so that is widely used by the per-bank-it usually has many branches in different locations. With a star configuration, then all sorts of activities at the branch offices it can be controlled and coordinated well. In addition, education also tend to use a star network is to control the activities of their students.

  3. Ring Networks (Network Ring)
    

 In this network there are several devices interconnected with each other and will eventually form the chart as well as a ring. Ring network does not have a point that acts as a central controller or data traffic, all nodes have the same level. The data sent will run through several nodes to arrive at the destination node. In presenting the data, the network may move in one or two directions. Nevertheless, data exist to keep moving in one direction at a time. First, there is a message which will be delivered from point to another in one direction. If the failure encountered, for example there is damage to the existing equipment, existing data will be sent by way of a second, then the message is transmitted in the opposite direction, and could eventually end up at the destination. Such a configuration is relatively expensive when compared with a star network configuration. This is due, each existing node will act as a computer that will solve every application that it faces, and must be able to share its resources on the existing network. In addition, the system is more suitable for systems that are not centralized (decentralized-system), which is not necessary to a certain priority.

   4. Tree Network (Network Tree)

    On the network tree, there are several levels of nodes (node). Central or higher level node, another node can set a lower level. Data sent through the central node needs 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, 5 and node-6 before ending in node-7. Keungguluan network model of a tree like this is, to the formation of a group that is required at all times. For example, companies can form a group consisting of terminal bookkeeping, and other groups formed for the sales terminal. The drawback is, if the node is higher then not working, then another group who are below it eventually becomes ineffective. How a tree network is relatively slow

 5. Bus Network

    Other configurations known as the bus-network, which is suitable for areas that are not too broad. Each computer (each node) will be connected with a communication cable through an interface. Each computer can communicate directly with a computer or other equipment located within the network, in other words, all nodes have the same position. In this case, the network is not dependent on a computer that is the center, so if any of the equipment or one node is destroyed, the system can still operate. Any node that has no address or nature itself. So for access to the data from one node, the user or wearer simply the address of the node in question. Bus topology advantages is the development of a network or adding new workstations can be done easily without disturbing the other workstations. The drawback of this topology is that if there are problems along the center of the entire cable network will be impaired.

  6. Plex Network (Network Combination)

    Network is a truly interactive, where each node has the ability to directly access not only to the computer, but also with other devices or nodes. In general, this network has a shape similar to a star network. Organization of existing data using the de-centralization, is to perform maintenance, use centralized facilities.

Logical topologies are generally divided form the two types, namely:

1. Topology Broadcast. It can simply be described is a host that sends data to all other hosts on the network media. 
2. Topology Token Passing. Arrange delivery of data on the host through the media by using a token that rotates on a regular basis throughout the host. Host can only send data only if the host has a token. By this token, collisions can be prevented.

Factors - factors that deserve consideration for the selection of the topology is as follows:

  1. Cost
    What are the most efficient system is needed in the organization.
  2. Speed
    To what extent is the speed required in the system.
  3. Environment
    Such as electricity or factor - in other environmental factors, which affect the type of hardware used.
  4. Size
    To how large the network size. Does the network need a file server or a dedicated server.
   5. Connectivity
    Are other users who use laptop computers to access the network from different locations.