Physical Components of a Computer Network

The physical components of a computer network refer to the hardware and transmission media that enable connectivity and data exchange between devices. These components include servers, clients, peers, transmission media, and connecting devices. A computer network consists of multiple computers linked together to facilitate resource sharing and communication.

In this section, we’ll explore the various physical components that make up a computer network.

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Types of Physical Components

A computer network consists of multiple devices that are physically connected to exchange vast amounts of data and services. Below are some key physical components:

1. Network Interface Card (NIC)

A Network Interface Card (NIC) is a hardware adapter used to connect a computer to a network. It is installed inside the system to establish Local Area Network (LAN) connectivity. Every NIC has a unique identifier and a connector that links to a cable, creating an interface between the computer and the router or modem. NICs operate on both the Physical and Data Link layers of the OSI model.

Types of NIC:

• Wired NIC: Uses cables to transfer data.
• Wireless NIC: Connects wirelessly via Wi-Fi, Bluetooth, etc.

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2. Hub

A Hub is a basic networking device that connects multiple computers in a network. It acts as a multiport repeater, forwarding incoming data packets to all connected devices. Hubs do not filter traffic or maintain routing tables, so all data is broadcast to every port, creating a single collision domain.

Types of Hubs:

• Active Hub: Amplifies and regenerates signals, suitable for long-distance transmission.
• Passive Hub: Does not amplify signals; suitable for short-distance networks.
• Switching (Intelligent) Hub: Operates at the Data Link Layer and uses MAC addresses to forward data selectively.

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3. Router

A Router is a network device that routes data packets based on IP addresses. Operating primarily at the Network Layer, routers connect different LANs or WANs and make routing decisions using dynamically updated routing tables. They also segment broadcast domains.

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4. Modem

A Modem (Modulator-Demodulator) is a device that connects a network to the Internet. It converts analog signals from telephone lines into digital signals and vice versa, enabling communication between digital devices and analog infrastructure.

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5. Switch

A Switch is a multiport networking device that operates at the Data Link Layer. It is more advanced than a hub and can filter and forward data selectively to the correct device using MAC addresses. Switches enhance network efficiency by reducing collisions and performing error checking before forwarding data.

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6. Nodes

Nodes refer to any active, addressable devices within a network. These devices can either initiate or receive communication.

Types of Nodes:

• End Nodes: Devices like computers, printers, and IP cameras that send or receive data.
• Intermediary Nodes: Devices like switches, bridges, and routers that direct traffic between end nodes.

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7. Transmission Media

Transmission media, also called network links, carry data from one device to another. They can be either wired (guided) or wireless (unguided).

7.1 Wired Medium

• Ethernet (IEEE 802.3): Most common LAN technology.
• Fiber Optic Cable: Uses light to transmit data; supports long-distance and high-speed transfer.
• Coaxial Cable: Used in cable TV and early Ethernet installations.
• USB Cable: Used for data transfer between PCs and devices.

7.2 Wireless Medium

• Infrared: Short-range communication (e.g., remote controls).
• Radio Waves: Used in Bluetooth and Wi-Fi.
• Microwaves: Common in cellular communication.
• Satellite: Enables long-range communication like GPS.

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8. Repeater

A Repeater is a device that regenerates and amplifies signals in a network to extend the distance over which data can travel. It operates at the Physical Layer of the OSI model and is essential for maintaining signal strength over long distances.

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9. Server

A Server is a specialized computer that provides services like file storage, web hosting, or communication to other computers (clients) in the network. Servers are equipped with high processing power and large storage capacity to handle multiple requests efficiently.

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