Computer Science · Ch 11 — Data Communication
Summary
Summary
- Data communication is the exchange of data between two or more networked or connected devices, such as laptops, PCs, printers, and routers.
- The major components of data communication are the sender, receiver, message, communication medium (channel), and protocol.
- Transmission media are the links that carry messages between communicating devices. They are broadly classified as guided (wired) media — a physical wire/cable link such as metallic cable or fibre-optic cable — and unguided (wireless) media, where data travels through air as electromagnetic waves using an antenna.
- The capacity of a channel is measured as bandwidth, expressed in Hertz (Hz).
- Communication can happen in three modes: simplex, half-duplex, and full-duplex.
- Switching techniques are an alternative to dedicated point-to-point lines: data is routed through intermediate nodes in the network, forming a temporary path for transmission. The two commonly used switching techniques are circuit switching and packet switching.
- The electromagnetic spectrum usable for wireless communication ranges from 3 KHz to 900 THz, divided into four categories: radio waves, microwaves, infrared waves, and visible/light waves.
- Bluetooth is a short-range wireless technology used to connect devices such as mobile phones, mice, headphones, keyboards, and computers wirelessly over a short distance.
- Mobile communication technologies are classified into generations based on the architecture of the mobile network: 1G, 2G, 3G, 4G, and 5G.
- A protocol is a set of standard rules that the sender, the receiver, and all intermediate devices need to follow. Flow control, access control, and addressing are examples of what a protocol governs.
- HTTP (HyperText Transfer Protocol) is the primary protocol used to access the World Wide Web, developed by Tim Berners-Lee at CERN in 1989. …