Switches are networking devices that connect devices together on a computer network and use packet switching to forward data to their destination. They work at the Data Link Layer (Layer 2) of the OSI model. Switches manage network traffic by maintaining a MAC address table that they use to filter and forward traffic only to the intended recipients, reducing overall network collisions and congestion. They can be managed or unmanaged; managed switches offer more features such as virtual LANs (VLANs) whereas unmanaged switches have pre-configured settings with limited functionality. These devices can be easily expanded to accommodate more network devices as the network grows, providing efficient traffic management.

Routers are specialized networking devices that connect two or more networks and forward packets between them using IP addresses. Routers operate at the Network Layer (Layer 3) of the OSI model, providing logical and physical path determination for data packets. They use routing tables and protocols to determine the best path for forwarding data, which allows remote networks to communicate with each other and maintain the required connectivity. Routers may filter, prioritize or redirect traffic, and they also employ security measures such as Access Control Lists (ACLs), stateful inspection, and VPNs to protect the networks they interconnect.

Wireless Access Points (WAPs) are networking devices that allow Wi-Fi-enabled devices to connect to a wired network. They serve as a central hub for wireless communications between devices and the rest of the network infrastructure. WAPs extend the range of a wired network and offer flexibility for device placement and mobility. They use various wireless standards such as IEEE 802.11a/b/g/n/ac to transmit and receive data. WAPs can operate in different modes, such as standalone or controller-based, and provide a variety of security features including encryption, MAC address filtering, and authentication methods (e.g., WEP, WPA, WPA2, WPA3) to ensure network integrity and confidentiality.

Modems (short for modulator-demodulator) are devices that enable communication between a local device (e.g., a computer or other network device) and the internet by converting digital signals to analog signals suitable for transmission over telephone or cable lines, and vice versa. Modems modulate and demodulate the data, allowing it to be sent and received over different types of networks with varying transmission methods. The speed at which modems transmit data is measured in bits per second (bps) or higher-level measures such as kilobits per second (kbps) or megabits per second (Mbps). Various types of modems are available, including traditional dial-up modems, DSL, cable, and fiber-optic modems.

Hubs are networking devices that act as a central connection point for devices within a local network to communicate with one another. They operate at the physical layer (Layer 1) of the OSI reference model, and their primary function is to transmit incoming data packets to all connected devices on the network, regardless of whether the data is intended for that device or not. This can lead to network inefficiencies and increased collision rates, as hub-connected devices have to compete for the limited available bandwidth to transmit their data. For this reason, hubs are generally considered an outdated technology in modern networks and are often replaced with more advanced devices like switches, which provide more efficient and intelligent data handling as they operate at the data link layer (Layer 2) of the OSI model.

Load balancers are specialized devices that distribute network traffic across multiple servers, ensuring that no single server is overwhelmed with too much traffic that could lead to decreased performance and increased response times. Load balancers can be implemented in both hardware and software, and they operate at different layers of the OSI model, with Layer 4 (transport layer) and Layer 7 (application layer) being the most common. They use a variety of algorithms, such as round-robin or least connections, to direct incoming traffic to the appropriate server, ensuring optimal use of available resources and maintaining high availability for network services. Load balancers can also detect unresponsive or excessively slow servers, and in such cases, they will automatically divert the network traffic to functioning servers, providing redundancy and minimizing service disruption.

Network-Attached Storage (NAS) is a dedicated file storage device that provides centralized, network-connected storage for multiple devices on a network. It allows devices to access and share files through common file-sharing protocols, such as NFS, SMB, or CIFS. NAS devices usually consist of one or more hard drives connected to the network, integrated with an operating system and specialized hardware to manage data storage and retrieval. They simplify storage management, enhance data availability, and offer added benefits like data backup, data protection, and data recovery. By centralizing storage, NAS devices reduce the need for direct-attached storage on each device, promote efficient resource usage, and facilitate collaboration and file sharing among users.

Network Gateways are devices that connect two or more networks that use different networking protocols, allowing devices on the connected networks to communicate with each other. They act as a translator, converting data from one protocol to another as necessary. Gateways can be implemented in both hardware and software, often as part of a router or other network device. Network gateways are essential for connecting networks with different infrastructures or ensuring communication between different network environments, such as connecting an enterprise network to the internet. Some common functions of network gateways include protocol conversion, address translation, data filtering, and traffic management.

A proxy server is an intermediate server between a client and the internet, used to process requests on behalf of the client. They can act as a buffer, increasing security by filtering and evaluating the traffic and hiding the client's IP address. Proxy servers are used to cache web content to speed up network performance, restrict access to specific websites or web services, monitor users' internet access, and protect networks from external attacks. By applying caching and content filtering rules, proxy servers can help organizations save bandwidth, enforce acceptable use policies, and protect their networks from malware and other security threats.

A network bridge is a networking device that connects two or more network segments at the data-link layer (Layer 2 of OSI model), allowing them to communicate as if they were part of the same physical network. Bridges inspect incoming data traffic, learn the MAC addresses of devices connected to various network segments, and make forwarding decisions based on this information. A bridge filters and forwards traffic based on MAC addresses, minimizing the amount of unnecessary traffic between network segments. Network bridges are useful when interconnecting networks with different topologies and media types, or in situations where network segmentation is necessary to reduce collisions and improve overall network performance.

A virtual local area network (VLAN) is a logical grouping of network devices, functioning as a separate subnetwork within a physical network. VLANs can span multiple switches or routers, and devices within a VLAN can communicate as if they are directly connected. By separating the network into distinct VLANs, network administrators can improve security, reduce traffic congestion, and simplify network management. VLANs are usually configured on managed switches or routers using VLAN tagging, wherein each data packet is tagged with a VLAN identifier to ensure it is forwarded only to devices in the same VLAN. This approach allows network administration to be more flexible, as VLAN grouping can be based on factors such as department, function, or security level, rather than physical location.