Network Topology: You Have to Know This Before Building a Network

Network Topology in a Nutshell

A network topology has physical and logical aspects. Physical topology has to do with the structure of the parts of a network that you can touch (overall). It determines how network devices, such as computers, routers, and stations connect to form a network. Logical topology is more concerned with getting data wherever it needs to go.

Physical topology involves:

  • Geometric configuration
  • Connections and interconnections
  • Location of devices
  • Number of network adapters used
  • Network adapter types
  • Cable types

Logical topology covers:

  • Data movement from station to station
  • The transmission path and appropriate protocols
  • Cloud and virtual networks

Point-to-Point Network Topology or P2P

This type of topology is the simplest of all. In Point-to-Point topology, there are only two computers or network devices that interconnect.

  • UTP Cat 5e
  • FTP Cat 5e
  • STP Cat 5e
  • RJ-45 connectors on both ends
  • T568A wiring on one end
  • T568B on the other end

Bus Network Topology

A bus network has one main cable. You connect stations to the main cable via shorter cables known as drop lines and use a tap device to connect drop lines to the main cable. To build a bus network, use RG-58 coaxial cable.. Usually, instead of direct bare-wire connections, you use connectors such as a BNC (Bayonet Neill-Concelman) connectors for connecting parts of the network and a cable to a network card. To avoid signal reflection, install devices that absorb signals called terminators on both ends of the cable. Signal reflection should be avoided at all times because it can slow down the whole network.

Token Bus

A Token Bus network utilizes a Token Ring protocol on a coaxial cable. A token is passed from station to station, and only the station that has the token can transmit frames in the network. A token is passed sequentially in a clockwise or counter-clockwise direction. The Bus Topology network employs IEEE 802.4 standard for building a logical token ring. IEEE 802.4 is currently disbanded by IEEE (SOURCE).

Ring Network Topology

A ring network is similar to a bus network, but it has a circular structure — every station is connected to the other station on each side, and the first station is connected to the last. A ring network operates in a half-duplex mode, which means that data in your network travels sequentially in one direction. A ring network also uses coaxial cables similar to bus network topology but it is faster than the bus network.

Token ring

The token-based topology implements the IEEE 802.5 standard (currently disbanded by IEEE). The token topology was suggested by IBM back in 1984. In the token ring topology, a token passes around the ring. Only the node that has the token can transmit data. The token ring topology has a medium installation difficulty — you only need to change two links to add or remove a network device, and the installation process is affordable. However, the token ring topology has many disadvantages such as:

  • Each fragment of ring topology is a point of failure
  • The whole network fails if the signal can’t pass the point of failure
  • Data has to go through all nodes before reaching its destination
  • Adding new stations can slow down the network because all stations in the network share the same bandwidth.
  • If you need to add or remove the node, the whole station should stay online

Dual ring

In the dual ring topology, there is a second connection between the nodes in the ring, which enables data transfer in both directions. Data travels in a clockwise and counterclockwise direction, and the networks work in a full-duplex mode. If one ring fails, the other one can take over to avoid an interruption in data transmission.

Optical ring

The optical ring structure involves expensive equipment, such as optical cables and switches. You can use this type of topology to connect stations located in different localities (different districts or cities) to form a high-speed loop. The optical ring topology is used in modern networks by internet service providers (ISP) and managed service providers to create connections in wide area networks.

Star Network Topology

The star topology is one of the most convenient. It is used by many organizations today. The star topology has a switch which is a central unit of the network. All other devices connect to this switch via a network cable. The central switch has numerous ports that allow stations to interact. All communication goes through the switch. When two stations interact, the data protocol from a sender is sent to the switch, and this switch then sends the data to the network card of the intended station.

Tree Network Topology

A tree topology is a more complex version of a star network. It allows you to bring together multiple star networks by connecting their switches. Every switch has a port, and you can connect several stations to those ports. Then you can connect those switches directly to the main switch.

Mesh Network Topology

In a mesh network topology, every station is connected to the other station. There are partial mesh and full mesh networks. A partial mesh has at least two stations connected to other stations in the network. In a full mesh, every station is connected to all other stations. Mesh networks ensure a continuous data transfer. If one station fails, other stations can still transfer your data. Setting up a mesh network can be expensive. You would need to create multiple connections and purchase a lot of cable.

Hybrid Networks

Hybrid networks are pretty popular nowadays. They involve a combination of two or more network topologies. But while hybrid networks can meet your unique needs, they have a few downsides. Hybrid networks are more complex and can be harder to install. They may also require extra cost. An example of a hybrid topology is a star-ring network. This network combines ring and star elements. This type of network implements high-quality fiber cables for making fast connections between buildings and cities. A fiber ring with numerous lines eliminates a single point of failure. Hybrid networks can be complex and hard to install, but they can be well worth it.

Conclusion

Since the 1970s, network topologies have evolved from simple P2P and bus architectures to complex hybrid systems. A star topology is a basic unit in modern hybrid networks. Building a network requires a lot of time and effort. You should estimate the current state of your company in order to choose a network topology that can best fit your needs. Before setting up a network of your choice, weigh all the pros and cons. Think about the size of your business and all related costs.

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