PLC network topology depicts the physical and logical organization of a communication network. There are five distinct network topologies that commonly exist: bus, ring, mesh, star, and tree.
Physical vs Logical Topology
The five topologies can be grouped under two main hierarchies:
Physical Topology
A physical topology is the arrangement of a network’s nodes and the connections that connect them. This comprises the connections between network nodes and their physical arrangement.
Logical Topology
A logical topology is the way data packets are routed over the network. The network’s logical topology is based on the protocols used by the data moving over it.
Five Types of Network Topologies
For computer networks, there are five primary topologies: star, mesh, bus, ring, and tree. Each one is categorized according on the arrangement of the nodes. The terminals are organized in a circular or starlike pattern in these topologies. A hybrid network is one that employs two or more topologies.
Star Topology
Each device in a star topology is connected to a central hub via a point-to-point link, which serves as the single switching device. This network is centralized, meaning that all devices connect to a central device. This provides simplicity because there is only one way to connect to each device in the network.
Additionally, the centralized nature of the network achieves isolation of each device, meaning that each device is only able to communicate with devices that are directly connected to it. This allows for the free-flowing exchange of data between devices.
The star topology is the simplest and cheapest topology. Each device runs independently, and a node’s failure to communicate with the central hub has no effect on other nodes. The downside of a star architecture is that network transmission is heavily reliant on the central hub. If a single node fails, the network as a whole becomes inoperable.
Advantages of the Star Topology
- The network’s design enables each computer to have its own cable connection, which means that if one computer is damaged or a cable breaks, the other computers will remain unaffected.
- Modifying, troubleshooting, and maintaining the network is simple.
Mesh Topology
A mesh topology is a sort of network topology in which each device in the network is connected to every other device. This topology is typically used in tiny networks where each device must communicate with the others. Each device in a mesh network is connected to every other device, resulting in a web-like appearance. Mesh topologies are more costly and difficult to configure than other topologies.
Bus Topology
In a bus topology, all devices are connected to a single cable. This enables the transmission of data from one device to another. While all devices on the network can hear all messages, only addressed devices will reply to them.
Even if one bus fails, communication can continue via a redundant bus. At any given time, only one device may utilize the shared transmission link. Each device that wishes to communicate data must first wait its turn and then transmit. The receiving device makes a copy of the traveling packet’s address. This topology is extremely adaptable and can support a large number of devices operating at varying data rates. A cable break can render a significant chunk of the network inoperable.
Bus Topology Advantages
- This architecture is quite inexpensive and straightforward to build.
- The bus topology is one of the simplest and most cost-effective topologies to implement.
- While it is generally slower and depends on the primary cable, it can easily be linearly expanded without interrupting the network.
Ring Topology
A ring topology is a network topology in which each node is connected to two more nodes. Additionally, the first and last nodes are connected. The network data is routed through each node in the ring until it reaches the destination node.
A central server is not required to manage connectivity between the nodes in a ring topology. As a result, it is a more robust and efficient network topology. The network’s capacity to transport data effectively is critical to its proper operation. However, the failure of a single station can render the entire network unworkable. Station alterations have an effect on the network’s operation. A ring topology is well-suited for networks with infrequent reconfigurations.
Ring Topology Key Advantages
- Requires no central device.
- Adding nodes has no impact on network performance.
- Relatively cheap and straightforward to implement.
Dual Ring Topology
The dual ring topology is distinguished by the presence of two connections between each node. In the two rings produced, data flows in opposite directions. The rings are not connected, and data flows in opposing directions via them. In the event that one ring fails, the other serves as a backup for data transfer.
Tree Topology
The tree topology architecture features a central bus that is connected to by star-shaped hubs. Essentially, it is a hybrid topology comprised of the bus and star topologies and reflects the use of the term “wide area network.”
