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Network Topologies: Definition, Types, and Importance

If a computer network were compared to the human body, the network cabling system would represent the nerves that make up the nervous system's outer appearance in the body. The network's functionality is determined by the cabling infrastructure that transports all data from one location to another. The way a network is cabled has a significant impact on how quickly it operates, how reliable it will be overall, and how simple it will be to update and grow the network. After determining the network's requirements, the first step with each new network is to decide how it should be connected. Other network components are then constructed on top of that base. Different topologies offer varying degrees of performance, dependability, and cost (both to construct and operate).

The shape of how computers and other networking devices are linked to each other is referred to as network topology. The word topology is formed by combining the Greek words topo and logy. "Topo" means "place" and "logy" means "study". It shows the placement and interconnection of nodes as well as the flow of data. The kind of configuration or topology determines network performance in computer networking. As a network administrator, you must have a thorough understanding of your network's topology. Without this knowledge, even simple troubleshooting might be excessively complicated.

This article will describe what a network topology is, and different types of network topology implementations including their advantages and disadvantages, and the importance of network topology. We will give key points for selecting the right network topology for your IT infrastructure as well.

What is Network Topology?

The OSI model is a widely used seven-layer architecture. The three levels at the bottom of these layers are addressed by the network topology. The physical layer is Layer 1. This refers to the tangible components of a network, such as the cables and the hardware. The logical connection layer is layer 2. Most current networks are built on Ethernet technology. There is Ethernet for LAN and WAN. Layer 3 is the network layer, and it is focused on internet protocols (IPv4, IPv6).

The configuration of different network components utilized for data transmission and the creation of connections between nodes and links is known as network topology. Network topology refers to the linking together of different components. There are two types of network topology:

  1. Physical topology
  2. Logical topology

The physical design of the network is represented physically by the topology of the physical links that are visible. When you identify a network, you create these interconnection maps in your mind, which is known as logical topology. It demonstrates the data flow inside an operational network. In such a way that a topological shape is produced when a map is created from the connections, and as a result, the network's physical topology is revealed. The logical topology, however, is formed by an awareness of the data flow details. So basically, the layout of multiple linked devices is the network topology. Even though this layout looks like a circle, it is not always a ring topology. The way the data is transferred and the devices are connected how the network topology will take shape.

Bus, Star, Ring, Mesh, Tree, and Hybrid topologies are the different shaped physical topologies. A network's design can directly affect how well it works. Because of this, businesses must choose the best topology for their network to boost performance and improve data efficiency. Additionally, the appropriate topology reduces operational expenses and optimizes resource allocation.

What are the Benefits of Network topology?

There are different network topologies with special features according to the purpose of use. Each network topology has its pros and cons. The primary benefits of network topology are as follows:

  • If you are aware of the details of the built network topology, you can understand how packets should arrive when one device has trouble interacting with another.
  • If the network topology is built properly, you can tell if there are firewalls in place or if there are specific bottlenecks where you can run into congestion issues or you may be aware of any single point of failure where a simple device or connection failure can have disastrous consequences.
  • In a Bus topology, it is simple to manage and implement. It is ideal for small networks and it is cheap to set up.
  • In a Ring topology, every hub has the opportunity to transmit information. Every one of the intermediary hubs is used to transmit information between two hubs. For the management of this topology, a core server is not required. The information is sent quickly and there is just one direction of traffic.
  • In Star topology, it enables ease of operation since it is centralized. Additionally, it achieves network device isolation for every device. It is simple to add or remove network nodes without impacting the network as a whole.
  • In Tree topology, it is best suited for system management in various business branches where each department operates independently and is also linked to the central hub. Secondary nodes can be added to the network to increase its size. So it is scalable.
  • In Mesh topology, it is possible to send data simultaneously from one hub to many other hubs. There are dedicated routes connecting any two network hubs, so it can manage heavy traffic.

What are the Disadvantages of Network Topology?

Each topology type has its disadvantages and risks. We can list the drawbacks of each network topology type as follows:

  • Both security and security response is impacted by the network topology. The occurrence and propagation of a breach become more difficult as the network becomes more segmented. Damage control and recovery are more important aspects of security than complete prevention, yet choosing the incorrect topology might increase the risk of this damage.
  • In a Bus topology, it is only effective for a small number of nodes. As more devices are connected to the bus, their efficiency decreases. It is difficult to identify errors within the network nodes.
  • In a Ring topology, a single network node's failure has the potential to bring the entire system down. A change to one of the nodes can affect the performance of the entire network.
  • In Star topology, the central hub's functionality is essential for network operation. As a result, when a central hub fails, the entire network also fails. The setup cost is high, and the hub's capacity determines how many nodes may be added.
  • In Tree topology, maintenance is difficult and expensive. Additionally, setup is challenging compared to other topologies.
  • In Mesh topology, expenses during installation and maintenance of the network are high because a lot of cabling is required.

What are the Types of Network Topology?

The form of the connections between the computers and other network components is referred to as the "topology" of the network. Network topologies come in a variety of types, each having pros and cons. Network topology types are listed below:

  1. Star Topology
  2. Bus Topology
  3. Ring Topology
  4. Mesh Topology
  5. Tree Topology
  6. Hybrid Topology

1. Star Topology

In Star topology, each network node is connected to a device known as a central hub or switch, making it simple to add new nodes without having to restart all of the presently attached devices. When a cable in a star network breaks, just the node attached to that cable is disconnected from the network. The other nodes can continue to operate properly.

There is a relatively technical difference between a hub and a switch. To put it simply, a hub does not know the computers that are connected to each of its ports. A switch, in contrast, is aware of the computers that are attached to each of its ports. Only switch-based networks have a real star topology. If the network employs a hub, the network architecture looks like a star but is a bus topology. This is because, just as in a bus architecture, when a hub is employed, each computer on the network sees all packets sent over the network. In a real star topology, such as when a switch is utilized, each computer sees only packets delivered directly to it, as well as packets sent explicitly to all computers on the network.

Star topologies are frequently used in local area networks. It can achieve very high data transmission rates, especially when the star coupler is employed in the switch mode. Among the various topologies, this is the easiest to maintain. But there are also some disadvantages related to this topology. The central hub's operation is critical to network operation. As a result, if the central hub fails, the entire network fails. In addition, the number of nodes that may be added is limited by the capability of the central hub.

Star Topology

Figure 1. Star Topology

2. Bus Topology

In the Bus topology, nodes are connected in a line. To understand how a bus topology works, imagine the entire network as a single cable, with each node "tapping" into it to listen in on the packets delivered over that wire. Every node on the network can monitor every packet delivered on the cable in a bus topology. Every packet is examined by each node to see if it is meant for that node. If so, the packet is claimed by the node. If not, the packet is ignored by the node. Each computer on the network will then be able to respond to data delivered to it and ignore data sent to other computers.

If the cable in a bus network breaks, the entire network is disabled. Because data cannot span the distance formed by the break, the nodes on opposite sides of the break can continue to interact with each other. Even nodes on the same side of the break may be unable to interact with one another because the open end of the cable left by the break disrupts the efficient transmission of electrical signals.

The use of a bus topology has various advantages. It's simple to add new devices, replace current devices, or uninstall old devices without impacting other connected devices, compared to other network topologies like mesh and star, less cable is used, and the cable can be quickly extended as needed.

Bus Topology

Figure 2. Bus Topology

3. Ring Topology

Ring topology is another type of network topology. Packets are passed from computer to computer in a ring topology. Each computer examines every packet to see whether it was meant for that computer. If not, the packet is sent to the next computer in the ring. A ring topology, despite what some people think, is not a physical arrangement of network cables. Rings are a logical arrangement; the real connections are wired like a star, with each node linked to the access unit through its cable. In contrast, the network operates electrically like a ring, with network signals traveling around the ring to each node in turn.

The most advantageous feature of the ring topology is the halving of the number of transmitters and receivers as compared to the linear topology. Additionally, unidirectional flows minimize packet collisions.

Ring Topology

Figure 3. Ring Topology

4. Mesh Topology

Each node in a mesh topology is connected to the others and can send and receive data as well as relay information from other nodes. Mesh topologies can be completely or partially linked mesh networks. The mesh topology is inflexible and poorly expandable because new nodes must be connected to each of the existing nodes by a dedicated connection, which requires the installation of all linkages before a new node can be added. The cost of cabling will be quite expensive for a broader region for the same reason. Although this design produces a very reliable network, it uses a lot of wire and is challenging to manage. This topology becomes more practical with WiFi networks. The benefit of a mesh topology is that if one cable breaks, the network may utilize another path to transmit its data.

Mesh Topology

Figure 4. Mesh Topology

5. Tree Topology

We can consider the tree topology as an extension of the bus topology. It's a hybrid topology that combines the star and bus topologies. When connecting to other nodes, the core parent node acts as a "bus" while the other child nodes spread the connections to its star topology. The name of this topology comes from the manner in which trees are organized. The network is made up of additional nodes that are stretched outward like branches out of a tree, with a central node or core acting as "the root or trunk" of the system.

It commonly appears in cascading devices. For instance, if your repeater box has six ports and you have six stations, you may use it normally. However, if you need to add more stations, you may do so by joining two or more repeaters in a tree-like hierarchy (tree topology). Because of their great scalability and flexibility, tree topologies are popular among wide-area networks (WANs). The most significant disadvantage of this topology is that centralization introduces the single-point-of-failure problem. If the central node has issues or a slow-down problem, the entire network is affected and falls.

Tree Topology

Figure 5. Tree Topology

6. Hybrid Topology

As the name indicates, a hybrid network architecture combines elements of many different topologies. The network's requirements determine how to create such a setup. Commonly, many topologies are used while designing modern networks. Network engineers, however, combine the benefits of each topology. This can be a useful method for easily connecting multiple existing networks into a single system. Star-ring and star-bus are the two most common hybrid topologies.

This topology also has several drawbacks and difficulties. Its potentially complicated architecture, for example, may make troubleshooting difficult, and depending on the setup, such a network might be resource-intensive to establish and maintain. Hybrid topology offers certain advantages as well; it combines the advantages of different topologies and, when performed properly, this form of topology is very adaptable and scalable.

Hybrid Topology

Figure 6. Hybrid Topology

How to Determine Your Network Topology?

A network's configuration, or topology, plays a crucial role in determining how well it performs. The configuration of a network, or its topology, includes a physical and logical specification of how links and nodes are structured in connection to each other. Before deciding on the network topology, you should consider the needs of the network you will install, your performance expectations, security requirement levels, and the costs to be spent during installation. After determining these, you should start by choosing the most suitable topology for your network.

  • In terms of network topology, there is no universal solution. What is ideal for one company could be completely unsuitable for another. You should consider the following important factors while selecting a network topology.
  • Given that more complicated network topologies would take more time and resources to set up, the installation cost is an important issue. Combining various components, such as joining a more sophisticated network structure using more expensive cables, might increase this.
  • If you are a professional at network management or hired one expert in your company, the complexity of the network topology you select may be unimportant. However, if you are going to assign an incompetent person who does not have IT knowledge to network setup, the simplicity of the topology should be a big consideration in your selection.
  • One of the most important factors is scalability. If you plan that your network can expand over time and you want to achieve this easily, you have to choose a network topology that will easily adapt to expansion. If a 10-device network topology were attempted to be applied to a 5,000-device company, the results could be disastrous. For example, the tree topology works stably for large companies, while the bus topology can be considered the most suitable topology for small businesses.

Which Network Topology is Best Used in a LAN?

A LAN is established to connect the necessary network devices so that personal computers or workstations can share all data among themselves. A special addressing scheme assigned by the TCP/IP protocol provides a connection between the computer and other devices with switches. In a local area network (LAN), Star topologies are most commonly used. In a very small LAN, like the one at your house, this is much more accurate. Because all other devices in the network are connected to a single central device at home.

Other LANs can commonly use star topologies as well. As an illustration, access switches are used in corporate networks where all hosts and computers are connected to the central switch. Although it uses a star topology. Apart from the Star topology, the Bus and Ring topologies are also used for LAN. The bus topology can cause slow transactions in the network, but it can also save cable expenses for installation.

Which Network Topology is Used in the WAN?

An extensive computer network known as a wide area network (WAN) links collections of computers over considerable distances. Big businesses commonly utilize WANs to link their office networks; normally, each office has its local area network (LAN), and these LANs communicate via a WAN. Wide Area Networks may use one or more different topologies. Which one is utilized for a specific WAN depends on the business requirements, the available space, and the cost-benefit analysis.

There are two distinct but connected views involved in applying the idea of topologies to WANs. The physical topology, which specifies the actual configuration of network components that enables data to transit from point A to point B, is one factor to take into account. The logical topology, which defines how data travels across the WAN, offers another viewpoint. The topologies that can be used for WANs are ring, star, and mesh topologies.

Where Should the Firewall be Placed in the Network Topology?

A firewall is a system, or group of systems, that maintains a distinction between two or more networks. A firewall can be software that runs on a computer, a specialized hardware box, access control lists (ACLs) running on a router, or any combination of these. To ensure that all traffic coming from outside the protected network passes through the firewall. A security policy determines which types of traffic are allowed to get in through the firewall. For proper security management, firewalls must be established between every network connected to the internet.

What is the Importance of Network Topology?

One of the main design components in the process of evaluating risk, impact, and cost is network topology. Different topologies offer alternatives and possibilities for regulating the size of the attack surface, the range and complexity of the attack, and the instruments available for detection, response, and recovery. When choosing a topology that maintains a balance between operational advantages and risk tolerance objectives, analysis of operational profits and losses should also be taken into account.

At this point, network topologies become even more crucial. Network topologies play an important role in network operation and help us better comprehend networking concepts. It is critical to performance and supports the reduction of operating and maintenance expenses, such as cabling costs. A network topology influences the type of device used to connect a network. Detecting errors or faults are simple with network topologies.