Network Topology

Network topologies describe the schematic arrangement of the network’s components (e.g. devices, nodes) and the relationship between them (i.e. how they communicate with each other).

Wired Star

The star topology is a prevalent wired topology that uses a central device, typically a hub or switch (though switches are usually the preferred option due to their higher performance and modernity), to manage the network. The central hub serves as an intermediary that indirectly connects all devices (including servers) and controls the flow of data.

Working in conjunction with servers, the central hub/switch ensures that all devices have access to required resources (e.g. internet, files). When a device needs to access a resource, it sends a request to the central hub/switch, which forwards the request to the appropriate server. The server then sends the requested resource back to the device through the central hub/switch. This centralized management helps maintain smooth data flow and prevents collisions.

Advantages

Scalability – easy to add/remove devices without needing to change the network layout as each device is separately connected to the central hub/switch.
Reliable – if a device fails or a cable disconnects, only one node will be brought down while the rest of the network can continue to operate without disruption.
High performance – the central core is responsible for managing the flow of data and ensuring the efficient transmission of data, reducing the likelihood of data collision and network congestion occurring on the network.

Disadvantages

Expensive – as each device requires its own cable, a lot of cables are needed as well as additional hardware pieces (i.e. hubs/switches).
Single Point of Failure – if the central core fails, all devices connected won’t have network connections and the entire network will likely be affected.
Limited Capacity – more suited to small to medium-sized networks (e.g. small business) as performance issues may arise if there’s too much traffic and the central hub/switch lacks the capacity to handle all the data transmission.

Image: Star Topology Diagram, Image by Jones IT (https://www.itjones.com/blogs/2020/11/22/a-guide-to-network-topology)

Wireless

Wireless network topologies utilise wireless signals to connect devices to the network without the need for cables or connectors. A wireless access point (WAP), which is connected to the network’s router/switch via an Ethernet cable, acts as the central hub of the network and broadcasts Wi-Fi signals that devices within range can connect to. This creates a wireless local area network (WLAN). However, in order to connect to a wireless network, devices will need to be equipped with a wireless adaptor, either built-in (e.g. phones, laptops, tablets) or externally added (e.g. via a USB wireless adapter for desktops).

In a wireless network, the process for requesting resources is similar to that of a wired network. For instance, when a laptop sends a request to print a document, it does so wirelessly to the WAP, which performs the same role as the central hub/switch would in a wired star topology. If the printer is wirelessly connected to the same network as the laptop, the WAP will transmit the request directly to the printer. However, if the printer is connected to the network through cables, the WAP will have to forward the request to the router/switch before it can reach the printer. Once the job has been completed, a message will be sent back to the laptop through the same path to notify the user.

Advantages

Cost Savings – since they require less hardware, especially cables, it reduces the costs associated with purchasing cables and hiring professionals to help route them.
Ease of Setup – installation and relocation are made easier as there are no physical connections that need to be disconnected and re-routed.
Convenient – the mobility and flexibility afforded by the lack of cables allow users to easily move around with their device.

Disadvantages

Range Limitation – all wireless signals have a limited range, beyond which no signals can be received.
Lack of Security – more vulnerable to unauthorised access and cyberattacks compared to wired networks as anyone within range can intercept wireless signals if the security measures implemented are insufficient.
Transmission Speed – when transmitting data wirelessly, there are a lot more factors that can affect the transmission speed, mainly the distance from the WAP and any physical barriers that disrupt signal strength (e.g. walls)

Image: Wireless Topology Diagram, Image by Dharshani Ranasoma (https://creately.com/diagram/example/g6n53ip01/wireless-network-diagram-template?r=v)

Client Server

The client-server topology is a network configuration where user devices (clients) are connected to a central computer (server), which provides services and resources to the clients. The server is responsible for providing access to services such as web browsing, file storage, printing, email, data backups, and security. This centralization of management makes it easier for the network administrator to manage and secure the network.

Advantages

Centralisation – a centralised approach to network management can offer numerous benefits. By controlling access to resources and services from a central point using a request-response system, administrators can easily implement security measures and restrictions on the use of websites and applications. It's also more convenient to store files and back up data in one place, making recovery easier in case of system failure.
Scalability – it can be easily expanded to accommodate more clients by adding or upgrading servers, making it a flexible option for growing networks.
Resource Sharing – resources such as printers and storage can be shared and accessed by all clients, increasing efficiency and collaboration.

Disadvantages

Expensive – requires a dedicated server that is powerful enough to handle all the network’s tasks and processing, which can be expensive to purchase and maintain.
Single Point of Failure – all clients rely on a single server to gain access to resources so if it fails or becomes overloaded due to too many client requests, the entire network may become non-functional.

Peer-to-Peer (P2P)

The peer-to-peer network topology doesn't have a distinct separation between clients and servers, unlike the client-server model. Instead, it consists solely of user devices that simultaneously function as both clients and servers, creating a decentralised environment that offers equal status to every device. This allows for resource sharing without a central server. For example, a printer can be shared by connecting a device and designating it as the “host”. The host device then plays the part of a server and grants other devices access to the printer by enabling printer sharing. Since every device is interconnected in a peer-to-peer network, other devices will be able to send printing requests directly to the printer.

Advantages

Cost-Effective – a budget-friendly option for small networks since they do not require the purchase, maintenance and/or upgrade of a server, nor the hiring of a network administrator to manage the network.
Easy to Setup – there is no particular structure or configuration that needs to be set up and it can be done without much additional hardware, making it simple for users to establish a peer-to-peer network.
Independent – a single point of failure does not exist as each computer is responsible for its resources, meaning that if one computer fails, the others will not be disrupted.

Disadvantages

Security Risks – without central management, it can be difficult to prevent access to dangerous/unproductive websites and ensure that all devices are adequately protected with updated antivirus software and firewalls as each device has its own separate security settings.
Limited Collaboration – resource sharing, particularly file sharing, is more difficult as there is no centralized location for storage or backup. To access a specific file, the device on which it is stored must be online, which can make collaboration and resource sharing more challenging.
Limited Scalability – as more devices are added to the network, the complexity of the network grows, and the number of connections each device has also increases. Without a central server to manage traffic and prioritise data transfers, devices must compete for a portion of the available bandwidth, causing performance issues such as slower data transfer speed.

Image: Client-Server vs. Peer-to-Peer Network, Image by MLSDev (https://mlsdev.com/blog/156-how-to-build-your-own-blockchain-architecture)

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