Chapter 1

• Data communication – refers to the exchange of data between a source and a receiver via form of transmission media or channel such as a wire cables or wireless transmission.
• Node – any active, physical, electronic device attached to a network
• Computer network – a system which multiple computers are connected to each other to share sinformation and resources. It allows data communication
• Purpose of computer networks – to share resources, to exchange file, for electronic communication.
• Basic element of data communication – source/transmitter, destination/receiver, communication link, communication protocols, message
• Segmentation – data is divided into smaller parts/segment packets
• Purpose of segmentation – if theres an error occur, you don’t need to resend all data, but the specific part of data only or segmented part that has an error
• Multiplexing – a technique which allows to send multiple signals over a single data link/ medium. It is the process of sharing the medium between multiple signals.
• Segmentation is needed before multiplexing
• Components of computer network – node or network node, network media, network interface card, network protocols, network software and services
• Node or network node – an electronic device that is attached to a network, and capable of creating, receiving or transmitting information over a communications channel. Types: end device, intermediary devices
• End device – refers to a piece of equipment that is either the source or the destination of a message on a network. Examples: server, desktop computers, printers, camera etc.
• Server – a computer that provides data or functionality. Server is a role not specific machine
• Intermediary device -  used to connect end devices to the network and can also be used to connect individual networks to form an internetwork. Classification: network access devices, internetwork device, modem
• Network access devices – within a network. Ex: network hubs, network switch, wireless access point
• Network hubs – connect multiple computers or network devices. It broadcast to all devices in the network the data that is send
• Network switch – connects devices on a computer network. But unlike hubs, it forwards the data to the intended recipient only. Unicast
• Wireless access point – like switch but wireless. Allows other wireless devices to connect to a LAN
• Internetwork device – connect multiple networks together. Ex: router
• Router – a networking device that forwards data packets between computer networks.
• Modem – modulator – demodulator. A networking device that converts digital signal to an analog signal or vice versa
• Modulation – digital to analog
• Demodulation – analog to digital
• Network media – the actual path over which the signal travels as it moves from one node to another. Example: COPPER – twisted pair cables, coaxial cables. GLASS – fiber optic cables. Electromagnetic waves
• Network interface card (NIC) – a computer hardware component that connects a computer to a computer network
• 1. Network protocols – a set of rules governing the exchange or transmission of data between devices. Example: http, https, smtp, ftp, ip, tcp
• Network software and services – web browsers, operating system, communication platforms, email applications, download applications.