Computer Networks Overview

A computer network covering a small geographical area, like an office or building, typically using cabling or wireless technology.

A computer network spanning a city or metropolitan area, often using fiber optic or wireless technology.

A computer network spanning a wide geographical area, covering a country or even multiple countries, using various technologies like fiber optics, satellites, and undersea cables.

An electronic device in a computer that allows it to connect to a network, enabling data sharing and communication with other devices.

A central device in a network that manages and controls access to shared resources like files, printers, hardware, and software.

A field value that contains the entities for example (an actual value)

An object about which data is stored

Uniquely identifies a record in a table/tuple in an entity

Consists of more than one attribute which uniquely identify an entity occurrence

A primary key in one entity which appears as a non-key in another entity as a link

If a foreign key is used it must correspond to a valid/existing primary key

A (non-key) attribute is stored more than once in the database/table

An attribute for an entity has more than one value

A database is in 1NF if it contains no repeating groups.

A database is in 2NF if it is in 1NF and contains no partial key dependencies.

A device that regenerates or amplifies signals during network transmission. It's especially useful for long-distance communication, preventing signal weakening or distortion.

A device that allows Wi-Fi enabled devices to connect to a network. It typically connects to a router and provides wireless coverage to a specific area.

A device that enables communication between two different network media types or protocols. For example, it can connect a fiber optic cable to a copper cable.

A unique identifier assigned to each network interface card (NIC) on a local area network (LAN). It identifies the physical address of the device.

A unique numerical address assigned to each device connected to the internet. It identifies the device's location on the network.

A network where all computers have equal status. Each device can act as both a supplier and consumer of resources, with control over its own resource sharing.

A network with a central server managing resources and security. Multiple client devices rely on the server for access and data.

A network topology where all devices are connected to a single main cable. Data can travel in both directions.

A network topology where devices are connected in a circular loop. A token is passed from one device to the next, allowing only the token holder to transmit data. Data travels in one direction.

A network topology with a central server connected to each device via individual cables. All communication within the network passes through the server.

A set of rules that govern communication between different devices, ensuring they understand and interpret data correctly

A model that divides network communication into seven distinct layers, each responsible for specific tasks, ensuring smooth and organized data flow.

The layer in the OSI model responsible for presenting information and data to the end user. It interacts with the Presentation layer and handles user interface functions.

The layer in the OSI model responsible for data formatting and presentation. It converts information into the correct formats for transmission and handles encryption and compression.

The layer in the OSI model responsible for managing communication sessions. It establishes connections for communication and maintains the flow of data.

The layer in the OSI model responsible for dividing data into packets and ensuring their reliable delivery. It also handles packet reassembly at the destination.

The layer in the OSI model responsible for routing data packets through the network. It determines the best path and adds addresses to each packet.

The layer in the OSI model responsible for error detection and correction, data block synchronization, and converting packets into bits for transmission. It interacts with the Physical layer.

The layer in the OSI model responsible for converting data into electrical or optical signals for transmission over the physical medium. It interacts with the Data Link layer.

A suite of protocols that defines how data is packaged, sent, and received on the internet. TCP handles file transfer and packet segmentation, while IP manages packet routing.

A networking protocol that defines the rules and physical connections for communication on a network. It covers the Physical and Transport layers of the OSI Model.

A set of rules that handle network collisions, where two devices try to transmit simultaneously. Ethernet networks use CSMA/CD to detect and resolve collisions.

A carrier for a packet that travels around a network, preventing packet collisions and ensuring orderly data transmission.

The process of detecting and resolving conflicts when two or more devices attempt to transmit data simultaneously on a shared network.

A short-range wireless communication technology that allows devices to connect and exchange data over a limited distance, typically within 10 meters.

A type of wireless technology using radio waves enabling computers to connect to a local area network (LAN) within a limited range, often 60-90 meters.

The range of frequencies or data rates available on a communication channel, determining the amount of data that can be transferred per unit of time.

High-speed internet access that is always connected, capable of handling multiple signals and data types simultaneously.

Transmission of voice calls over computer networks, converting analog voice signals into digital data packets.

A small tag containing a microchip storing data, activated by radio waves emitted from a reader. The tag transmits data back to the reader, enabling identification and tracking.

A method of data transmission using thin strands of glass to transmit light pulses at high speeds over long distances, providing secure and interference-free communication.

A method of data transmission using different types of copper cabling to transmit electrical signals over shorter distances. Examples include coaxial cable and twisted pair.

A method of data transmission using radio waves to transmit data between devices without physical cables. Examples include Bluetooth and Wi-Fi.

A method of detecting errors in data transmission by appending a parity bit to each byte. The parity bit reflects whether the number of 1 bits in the byte is odd or even.

A method of error detection by calculating a checksum value from a block of data and appending it to the block. The checksum is recalculated upon reception, and any mismatch indicates an error.

A method of error detection and correction where the receiver sends back a copy of the received data to the sender for comparison. Any discrepancy triggers retransmission of the original data.

A method of error detection and correction using a mathematical algorithm to calculate a checksum, called a CRC, for a block of data. Any discrepancy in the CRC upon reception indicates an error.

A type of database organized as a collection of tables linked together through relationships. Data is structured in rows (records) and columns (attributes), and relationships are established using primary and foreign keys.

A data model that describes the logical structure of a database independently from the underlying software implementation. It defines entities, relationships, attributes, and primary/foreign keys.

A data model that specifies the physical implementation of a database, including details like tables, columns, data types, and storage mechanisms.