# Introduction

## **Networking**

* **Computer Network:** A set of interconnected computers sharing resources and data.
* **Importance:** Facilitates communication, resource sharing, and data management. Enables services like email, the internet, and cloud computing.

## **Node**

 A node is any device connected to a network. This includes computers, printers, routers, switches, or any other device that can send, receive, or forward information.

* **Functions:**
  * **End Nodes:** Devices like computers and printers that generate or consume data.
  * **Intermediary Nodes:** Devices like routers and switches that direct data flow within the network.
* **Identification:** Nodes are identified by unique addresses, such as IP addresses in an IP-based network.

## Communication Link

A communication link is the physical or logical connection that enables data transmission between two or more network nodes. It is a fundamental component of a network, ensuring that devices can exchange information effectively.

### **Types of Communication Links:**

* **Wired Links:**
  * **Twisted Pair Cable:** Consists of pairs of insulated copper wires twisted together. Commonly used for telephone lines and Ethernet cables (e.g., Cat5, Cat6).
  * **Coaxial Cable:** Has a single copper conductor at its center with a plastic layer providing insulation and a metallic shield. Used for cable TV and internet connections.
  * **Fiber Optic Cable:** Transmits data as light signals through strands of glass or plastic fibers. Offers high speed and long-distance transmission, commonly used for backbone connections.
* **Wireless Links:**
  * **Radio Waves:** Utilized in Wi-Fi networks, Bluetooth, and cellular communications. They provide mobility and convenience but are susceptible to interference.
  * **Microwaves:** Used for long-distance communication, including satellite links and some Wi-Fi standards.