2016年5月3日星期二

Network Topology

Network topology is the arrangement of the various elements (links, nodes, etc.) of a computer network. Essentially, it is the topological structure of a network and may be depicted physically or logically. Physical topology is the placement of the various components of a network, including device location and cable installation, while logical topology illustrates how data flows within a network, regardless of its physical design. Distances between nodes, physical interconnections, transmission rates, or signal types may differ between two networks, yet their topologies may be identical.


An example is a local area network (LAN): Any given node in the LAN has one or more physical links to other devices in the network; graphically mapping these links results in a geometric shape that can be used to describe the physical topology of the network. Conversely, mapping the data flow between the components determines the logical topology of the network.


Bus Topology: In networking a bus is the central cable -- the main wire -- that connects all devices on a local-area network (LAN). It is also called the backbone. This is often used to describe the main network connections composing the Internet.  Bus networks are relatively inexpensive and easy to install for small networks. Ethernet systems use a bus topology. The advantage is it's easy to connect a computer or device and typically it requires less cable than a star topology. The disadvantage is the entire network shuts down if there is a break in the main wire and it can be difficult to identify the problem if the network shuts down.


Ring TopologyA local-area network (LAN) whose topology is a ring. That is, all of the nodes are connected in a closed loop. Messages travel around the ring, with each node reading those messages addressed to it. One main advantage to a ring network is that it can span larger distances than other types of networks, such as bus networks, because each node regenerates messages as they pass through it.


Star Topology: In a star network devices are connected to a central computer, called a hub. Nodes communicate across the network by passing data through the hub. The advantage is in a star network, one malfunctioning node doesn't affect the rest of the network. But if the central computer fails, the entire network becomes unusable.



Chua Guan Ming      1001540244

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