networking-devices

Modem

• Physical Layer

• Serves as the bridge between digital devices (like computers) and the transmission medium (like phone lines, fiber, or cable) that may require analog signals.

• Short for modulator-demodulator. It performs modulation (Digital → Analog) and demodulation (Analog → Digital) to convert signals for transmission.

Hub

• Physical Layer

• Connects multiple computers or devices in a local area network (LAN). Hubs receive incoming data signals from one port and broadcast them to all other ports.

• Inefficient use of bandwidth, less commonly used today, as switches are more efficient.

Repeater

• Physical Layer

• Extends the range of a network by amplifying or regenerating signals over long distances.

• Often used in large networks or to extend signal coverage in areas with poor connectivity.

Switch

• Data Link Layer

• Connects multiple devices (like computers, printers, or servers) in a local area network (LAN) using wired connections (Ethernet cables) and forwards data only to the device that needs it.

• Stores and uses MAC addresses in a CAM (Content Addressable Memory) table to forward data more efficiently.

WAP (Wireless Access Point)

• Data Link Layer

• Provides wireless connectivity to devices in a local area network (LAN).

• Allows devices like laptops, smartphones, and tablets to connect to the network wirelessly by transmitting and receiving data using radio waves.

Bridge

• Data Link Layer

• Connects separate network segments together.

• More efficient than hubs, as it filters traffic and reduces collisions between network segments.

Router

• Network Layer

• Responsible for directing data packets between different networks, typically between a local network (like your home network) and the internet

Firewall

• Network Layer / Transport Layer

• Protects a network from unauthorized access, typically by filtering traffic based on rules.

• Can be hardware (A physical device connected to the router) or software-based (modern routers have built-in firewall software) and helps secure network boundaries.

• A firewall can be either stateless or stateful

IDS (Intrusion Detection System)

• Security system that monitors network or system activities for signs of malicious activity.

• Detects attacks but doesn’t block them.

IPS (Intrusion Prevention System)

• Security system that monitors network or system activities and actively blocks malicious activities.

• Detects and actively blocks attacks.

VPN concentrator

• A device that manages and secures multiple VPN connections, allowing remote users or sites to securely access a private network.

• Less used nowadays

Load Balancer

• Transport Layer / Application Layer

• Distributes traffic across multiple servers to improve performance and reliability.

• Helps prevent overloading a single server and ensures high availability of services.

Proxy Server

• Application Layer

• Sits between users and the internet to control access and improve privacy (hides and protects the requesting client)

• Can save (cache) web data to load pages faster and reduce internet use.

Gateway

• Various Layers, depending on function and placement in network

• Connects separate networks with different protocols or technologies.

• Often acts as a translator between different network architectures or protocols.