What is Topology?
A topology is configuration of communication networksand is of two types, Physical and Logical. Physicaltopology refers to configuration of computers, cables, devices and mostly depends on various factors. A logical topology is a method of transmitting or passing data between workstations.
Types of Physical Topologies
- Bus Network (also known as Liner Bus)
- Star Topology (Centralization)
- Ring Topology (also known as Star-Wired or Token Ring Network)
- Tree
- Mesh Topology
Bus Network
A bus network is a network architecture in which a set of clients are connected via a shared communications line, called a bus. There are several common instances of the bus architecture, including one in the motherboard of most computers, and those in some versions of Ethernet networks.
Star Topology
In a Star Topology each computer is directly connected to the centralized Hub or a Switch. In this way, when computer A sends a data packet for computer B, the data flows through the Hub or Switch to which both computer A and B are connected. Different types of cables can be used in this scenario like coaxial cable, fibre optic cable and twisted pair cable.
Token Ring / Star-Wired
A token ring topology is architecturally similar to star topology. The only difference here is that it is created of wiring that would allow transfer of data from one computer to another in a ring (or circle). A token ring network will pass information based on token system.
Tree
A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable. Tree topologies allow for the expansion of an existing network with ease.
Mesh Topology
A fully connected or complete topology is a network topology in which there is a direct link between all pairs of nodes. In a fully connected network with n nodes, there are n(n-1)/2direct links. Synonym fully connected mesh network.
In a mesh topology, there are at least two nodes with two or more paths between them. A special kind of mesh, limiting the number of hops between two nodes, is a hypercube. The number of arbitrary forks in mesh networks makes them more difficult to design and implement, but their decentralized nature makes them very useful. This is similar in some ways to a grid network, where a linear or ring topology is used to connect systems in multiple directions. A multi-dimensional ring has a toroidal (torus) topology, for instance.
Considerations
Consider the following when choosing a topology:-
- Future Growth: Is the network for temporary use or will undergo lot of growth in the future. Plan it accordingly.
- Money: What is your budget? What will be the purpose of this network?
- Cable Media: Type of cable that should be used as per the standards.
- Length of the cable: How far are your systems placed in the network? Is it the same building that your systems will be placed in or if your office is in two floors which should be connected?
Summary
See the below table for a quick understanding and comparison of topologies, cable media and protocols used.
| Topology | Cable Media | Protocols Used |
|---|---|---|
| Linear Bus | Twisted Pair Coaxial Fiber | Ethernet LocalTalk |
| Star | Twisted Pair Fiber | Ethernet LocalTalk |
| Token / Star-Wired Ring | Twisted Pair | Token Ring |
| Tree | Twisted Pair Coaxial Fiber | Ethernet |
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