Network Topology

Network topology is the layout or organizational hierarchy of interconnected nodes of a computer network. Different network typologies can affect throughput, but reliability is often more critical. With many technologies, such as bus networks, a single failure can cause the network to fail entirely. In general the more interconnections there are, the more robust the network is; but the more expensive it is to install.

Common layouts

• Bus topology: all nodes are connected to a common medium along this medium. This was the layout used in the original Ethernet,  called 10BASE5 and 10BASE2.
• Star topology: all nodes are connected to a special central node. This is the typical layout found in a Wireless LAN, where each wireless client connects to the central Wireless access point.
• Ring topology: each node is connected to its left and right neighbor node, such that all nodes are connected and that each node can reach each other node by traversing nodes left- or rightwards. The Fiber Distributed Data Interface (FDDI) made use of such a topology.
• Mesh topology: each node is connected to an arbitrary number of neighbors in such a way that there is at least one traversal from any node to any other.
• Tree topology: nodes are arranged hierarchically.

Note that the physical layout of the nodes in a network may not necessarily reflect the network topology. As an example, with FDDI, the network topology is a ring (actually two counter-rotating rings), but the physical topology is often a star, because all neighboring connections can be routed via a central physical location.

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