What is network topology?
Network topology refers to the arrangement of elements within a network. Essentially, network topology is the design, and network diagrams are the visuals that document that design. Network topologies can describe either the physical or logical aspects of a network. Logical topology is also known as signal topology.
Different topologies are best for certain situations, since they can affect performance, stability, and other outcomes.
Bus topology
Also known as the backbone, linear, or Ethernet topology, this type of network is distinguished by having all of the nodes connected by a central medium (the "bus"), which has exactly two endpoints.
Bus topologies are easy to configure and require less cable length than some other topologies. However, if the central bus breaks down, so does the whole network, and it can be difficult to isolate the problem.
Ring topology
Nodes are connected in a circular pattern, and packets of information are sent through the ring until they reach their destination.
Ring networks can outperform those based on the bus topology, and they can be easily reconfigured to add or remove devices. However, they are still relatively vulnerable, since the whole network fails if a single node fails. Also, bandwidth must be shared across all the devices and connections.
Star topology
One of the most common topologies, the star topology consists of a central hub or switch through which all of the data passes, along with all of the peripheral nodes connected to that central node.
Star topologies tend to be reliable because individual machines may crash without affecting the rest of the network. But if the central hub or switch fails, none of the connected nodes will be able to access it. Cable costs also tend to be higher for star networks.
Mesh topology
There are two types of mesh topology. In the first, which is called full mesh topology, each node is directly connected to every other node.
In a partial mesh topology, nodes are only connected to the nodes they interact with most.
Most networks employ some combination of topologies to yield what's called a hybrid topology. For instance, the tree topology combines the bus and mesh topologies.
The logical and physical topology of a particular network may resemble one another, or they may be entirely different. For example, a twisted pair Ethernet network exists as a star topology physically but follows the bus topology logically.
