Network Topology

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Network topology refers to the configuration of the physical and logical connections between the elements (links, nodes, etc.) of a network. Network topology does not refer to the physical layout of a network, nor does it refer to transmission rates, signal types or other characteristics of computer networks. Networks are normally organized by one (or more) of five basic types of topologies: bus, ring, star, tree, and mesh. In some instances two networks are interconnected forming a sixth type of topology: hybrid.


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Types of Network Topology

Bus

The bus topology uses a single transmission medium on which all messages are broadcasted. Each node receives all messages, but only the intended destination accepts it. Only one message can be sent at a time.

Advantages
  • Requires a minimal amount of connections.
  • Simple configuration.
Disadvantages
  • A fault in the main cable can bring down the entire network.
  • Very unsafe. Each computer receives all messages on the network. A computer can still accept messages even if its address does not match the destination address.
  • Is slow, and prone to collision problems.

Ring

In a ring topology each node is connected to exactly two other nodes forming a closed loop. Messages are passed along the ring in a single direction until they reach their destination.

Advantages
Disadvantages

Star

The star topology consists of a hub, router, etc., connecting each other node of the network. Each message passes through the hub and is redirected to its destination.

Advantages
  • Easy to detect errors and faults. Each node is separate from all other nodes through the hub, so it is easy to isolate and fix the problem.
  • Any break in a connection between the hub and a node will not cause a failure in the network.
Disadvantages
  • If the hub has a fault, the entire network can fail.


Tree

Combining multiple star networks along a single bus network with a root node forms the tree topology.

Advantages
Disadvantages

Mesh

Mesh topologies present multiple paths that a message can take to reach their destination. Each node can be connected with n-1 other nodes, where n is the total number of nodes on the network. If each node is connected with n-1 nodes, then the mesh network is referred as being fully connected or as a full mesh.

Advantages
Disadvantages

Centralization

Decentralization

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