Network Topologies at a Glance

A network is basically all of the components (hardware and software) involved in connecting computers across small and large distances. Networks are used to provide easy access to information, thus increasing productivity for users.

What is network topology?

In simple words, Network Topology is configuration of a communication network.

What are different types of network topology?

Point-to-Point topology:

A point-to-point topology has a single connection between two devices. In this topology, two devices can directly communicate without interference from other devices. These types of connections are not common when many devices need to be connected together. An example of a point-to-point topology is when you connect two routers across a dedicated WAN circuit.

Star topology:

In a star topology, a central device has many point-to-point connections to other devices. Star topologies are used in environments where many devices need to be connected. An example of a media type that uses a star topology is 10BaseT Ethernet. When connecting devices together, you connect your computers to a hub or switch (the center of the star). An extended star topology is basically multiple star topologies interconnected.

Bus topology:

A bus topology uses a single connection or wire to connect all devices. Certain media types, like 10Base5 and 10Base2 Ethernet, use a bus topology. Typically, special types of connectors or transceivers are used to connect the cables in order to provide the bus topology. In 10Base5, for example, each device connects to a single strand of coaxial cable via a vampire tap. This device taps into the single strand of coaxial cable and provides the physical connection from a networking device to the single strand of cable.

Ring topology:

In a ring topology, device one connects to device two, device two connects to device three, and so on to the last device, which connects back to device one. Ring topologies can be implemented with a single ring or a dual ring. Dual rings are typically used when you need redundancy. For example, if one of the devices fails in the ring, the ring can wrap itself, to provide a single, functional, ring. Fiber Distributed Data Interface (FDDI) is an example of a media technology that uses dual rings to connect computer devices.

How does physical topology differ with logical topology

A distinction needs to be made between physical and logical topologies. A physical topology describes how devices are physically cabled together. For instance, 10BaseT has a physical star topology and FDDI has a physical dual ring topology. A logical topology describes how devices communicate across the physical topology. The physical and logical topologies are independent of each other. For example, any variety of Ethernet uses a logical bus topology when devices communicate. This means that in Ethernet, you might be using 10BaseT with a physical star topology to connect devices together; however, these devices are using a logical bus topology to communicate.

Token Ring is actually a good example of a media type that has a different physical topology from its logical one. Physically, Token Ring uses a star topology, similar to 10BaseT Ethernet. Logically, however, Token Ring devices use a ring topology to communicate. This can create confusion when you are trying to determine how devices are connected together and how they communicate.

What is Meshing?

Meshing generically describes how devices are connected together. There are two types of meshed topologies: partial and full. In a partially meshed environment, every device is not connected to every other device. In a fully meshed environment, every device is connected to every other device.