Florida Center for Instructional Technology. College of Education ,. University of South Florida ,. This publication was produced under a grant from the Florida Department of Education. The information contained in this document is based on information available at the time of publication and is subject to change.
Although every reasonable effort has been made to include accurate information, the Florida Center for Instructional Technology makes no warranty of claims as to the accuracy, completeness, or fitness for any particular purpose of the information provided herein. Nothing herein shall be construed as a recommendation to use any product or service in violation of existing patents or rights of third parties. What is a Topology?
Main Types of Physical Topologies The following sections discuss the physical topologies used in networks and other related topics. Linear Bus topology. Star topology. Tree topology. If the common cable fails, then your entire network will crash. Additionally, as a half-duplex, data can only be transmitted in one direction along the cable at any given time, making congestion a common problem.
As more network nodes begin to rely on the main cable, data transmission rates will slow. Ideal for high-value, small to mid-sized networks, mesh topology consists of interconnected nodes, making it a fast and secure choice. In a full mesh network topology, each node is connected to all the other nodes via direct link, creating point-to-point connections.
In a partial mesh topology, most nodes are interconnected, but some nodes only connect with a few others via point-to-point links. Data transmitted within a mesh topology is sent through routing or flooding. As you might expect, it takes several cables to connect each node to all the other nodes, which means installing mesh topology can get expensive quickly, takes a considerable amount of time to set up, and requires a lot of configuration. Consequently, this topology is difficult to administer and costly to maintain.
As its name implies, ring topology consists of a ring of devices connected to two adjacent devices via point-to-point links, with the first and last nodes linking the loop. You can conveniently monitor your devices and configure the network through one node. Ring topologies are half-duplex, so data can only be sent in one direction at a time, and data will pass through each network node on its way to its target device.
In a ring topology, the node possessing the token is the only node capable of transmitting data, reducing the possibility of a collision. With early token release, the node releases the token as soon as it transmits the data, while with delayed token release, the node holds onto the token until it receives an acknowledgment from the receiver that the data has been received.
Thanks to its low installation costs, high data transmission rates, and low incidences of collision, many small businesses use a ring topology. Dual ring topologies are particularly redundant, providing continuity for the network. This topology is vulnerable to failure, as if just one node fails, the entire network will go down.
Dual ring topologies function in the same manner as ring topologies with one key difference: they can send data in both directions, making them full-duplex and more efficient.
Each node has two connections on both sides, enabling the transmission of data in both directions. In addition to all the benefits ring topology offers, dual ring topology is redundant, thanks to the second ring, which can send data if the other ring fails. Named for its tree-like shape, the tree network topology has a hierarchical layout with at least three different levels.
The tree topology consists of the central hub, secondary hubs, and devices. Data will flow from the central hub to a secondary hub to a device or from a device to a secondary hub to the central hub. Under this hierarchical format, it is easy to add more nodes to the network when your organization grows in size. This format also lends itself well to finding errors and troubleshooting because you can check for network performance issues systematically throughout the tree. The most significant weakness of tree topology is the root node.
If the root node fails then all of its subtrees become partitioned. Maintaining the network system is not simple either because the more nodes you add, the more difficult it becomes to manage the network. Another disadvantage of a tree topology is the number of cables you need. Cables are required to connect every device throughout the hierarchy which makes the network layout more complex when compared to a simpler topology.
A mesh topology is a point-to-point connection where nodes are interconnected. In this form of topology, data is transmitted via two methods : routing and flooding. In contrast, flooding is where data is sent to all nodes within the network. There are two forms of mesh topology : partial mesh topology and f ull mesh topology. With partial mesh topology, most nodes are interconnected but there are a few which are only connected to two or three other nodes.
A full mesh topology is where every node is interconnected. Mesh topologies are used first and foremost because they are reliable. The interconnectivity of nodes makes them extremely resistant to failures. There is no single machine failure that could bring down the entire network. The absence of a single point of failure is one of the reasons why this is a popular topology choice. This setup is also secure from being compromised. However, mesh topologies are far from perfect. They require an immense amount of configuration once they are deployed.
The topological layout is more complex than many other topologies and this is reflected by how long it takes to set up. When a topology is composed of two or more different topologies it is referred to as a hybrid topology. Hybrid topologies are most-commonly encountered in larger enterprises where individual departments have network topologies that different from another topology in the organization. Connecting these topologies together will result in a hybrid topology.
As a consequence, the capabilities and vulnerabilities depend on the types of topology that are tied together. There are many reasons why hybrid topologies are used but they all have one thing in common: flexibility. There are few constraints on the network structure that a hybrid topology cannot accommodate, and you can incorporate multiple topologies into one hybrid setup. As a consequence, hybrid topologies are very scalable.
The scalability of hybrid setups makes them well-suited to larger networks. Unfortunately, hybrid topologies can be quite complex , depending on the topologies that you decide to use. Each topology that is part of your hybrid topology will have to be managed according to its unique network requirements.
In addition, setting up a hybrid topology can end up being quite costly. See also: Network Discovery Tools and Software. There is a range of factors that you need to take into account when choosing which topology to use. First, you need to take into account the length of the cable you need to provide service to all your network devices. A bus topology is the most lightweight in terms of cable needs. In this sense, this would be the simplest topology to install and buy cables for.
Cable types range from twister pairs to coaxial cables and optical fiber cables. The cost of installing the topology is also very important.
A star topology network is ideal for this because you can add network nodes with minimal disruption. Now that we know the different types of topology, it is time to consider how to design your network from scratch.
There are several software products that allow you to create your own network topology diagrams. Network topology diagrams show you a diagram of how your network connects together and helps you to create an efficient network design. It also provides you with a reference point that assists you when you attempt to run troubleshooting to fix faults. We reviewed the market for network topology mapping software and analyzed the options based on the following criteria:.
Microsoft Visio. There are many different network topology mapping products out there but one of the most widely-used is Microsoft Visio. With Microsoft Visio, you can draw up your network by adding network elements to a canvas.
This program allows you to design a topology diagram that details your network. As a result, you might want to consider using another tool like SolarWinds Network Topology Mapper which can autodiscover devices connected to your network. The network topology you choose for your enterprise should be deeply rooted in your usage requirements. Using a tool like SolarWinds Network Topology Mapper will allow you to plot your network on a diagram to view your topological structure in one place. The best cabled network topology for large businesses is the star topology.
This is because it is easier to control from a central console as the management software just needs to communicate with the switch to get full traffic management features.
A hybrid topology is sometimes encountered as a temporary solution to connect together departments while a new unified system is being planned.
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