Communications Technology - Networks and Data Transmission

Comprehensive vocabulary flashcards covering computer networks, servers, cloud computing, data transmission, protocols, routing, the OSI and TCP/IP models, wireless media, security threats, and disaster recovery management.

Network

Two or more computers or devices connected together so they can communicate and share data and resources.

Local Area Network (LAN)

A network limited to a small geographic area, such as a single building, campus, or group of closely located buildings, featuring high data transfer speeds up to $1\,\text{GB/s}$.

Wide Area Network (WAN)

A computer network that spans a large geographical area, connecting multiple LANs and network devices across countries, with the Internet being the largest example.

Client-Server Network

A network architecture where servers act as central points of control providing dedicated functions to client computers using a request-response method.

File Server

A server that stores and manages data files centrally, eliminating extensive local storage needs on client devices and allowing centralized data backups.

Web Server

A server responsible for storing, processing, and transmitting web pages to client devices over a network.

Mail Server

A server that receives, stores, and forwards emails, while scanning incoming messages for security issues like viruses, malware, and spam.

Application Server

A server that installs and runs software applications, providing a shared platform to execute desktop and web applications across a network.

Print Server

A server that receives, queues, and routes print jobs from client computers to the correct or next available printer on the network.

FTP Server

A server that manages file transfers using the File Transfer Protocol (FTP) and maintains a log of all FTP activity.

Proxy Server

An intermediary server that forwards client requests to other servers, adding network security, masking IP addresses, and potentially acting as a firewall.

Virtual Server

A software-based server created using virtualization software that shares the hardware of a single physical server.

Peer-to-Peer (P2P) Network

A decentralized network where each connected computer (peer) has equal status and shares resources directly without relying on a central server.

BitTorrent

A peer-to-peer communication protocol where nodes share the workload of simultaneously downloading and uploading pieces of files without a central server.

Swarm (BitTorrent)

A collection of multiple sources or hosts gathered together in BitTorrent to share pieces of a particular file.

Seed (BitTorrent)

A BitTorrent user who has downloaded pieces or the entirety of a file and provides the upload of that file to other peers.

Virtual Private Network (VPN)

A technology that encrypts internet connections to provide privacy, anonymity, and secure remote access to corporate or private networks.

Internet Protocol Security (IPSec)

A protocol suite operating at the Internet layer that authenticates and encrypts data packets sent across the internet, commonly used in VPN tunneling.

Tunneling

The process of encapsulating private IP packets inside public IP packets so they can travel securely across public communication networks.

Mobile Network (Cellular Network)

A wireless WAN that uses radio waves transmitted between base stations and portable devices, divided into geographical areas called cells.

Cell (Mobile Network)

The specific geographical area within a cellular network covered by an individual radio transmitter and base station.

5G Mobile Network

The fifth generation of mobile networks, offering speeds tested up to $1.5\,\text{Gbps}$, very low latency, and support for up to $1\,\text{million devices/km}^2$.

Beam-forming

A signal processing technique used by base stations in mobile networks to direct radio signals toward specific devices to improve connection quality.

Network Interface Card (NIC)

A hardware component operating at the Data Link Layer that encapsulates data into frames, assigns MAC addresses, and connects a device to a network.

MAC Address

A unique hardware identifier assigned to an NIC by its manufacturer, consisting of a manufacturer ID and serial number, used for local network addressing.

Wireless Network Interface Card (WNIC)

A network card that uses radio waves to transmit and receive data wirelessly, enabling connectivity to a Wireless Access Point (WAP).

Repeater

A Physical Layer network component that amplifies, regenerates, and retransmits incoming signals to compensate for degradation and remove noise.

Hub

A Physical Layer hardware device that connects multiple computers and forwards all received data packets to every connected device indiscriminately.

Switch

A Data Link Layer device that inspects the destination MAC address of incoming packets and forwards them exclusively to the intended recipient device.

Wireless Access Point (WAP)

A networking device that allows wireless devices to connect to a wired network within a designated coverage area using radio signals.

Service Set Identifier (SSID)

The unique identifying name of a wireless local area network that devices use to locate and connect to a Wireless Access Point.

Gateway

A device or software that connects two or more different networks that use different protocols, enabling inter-network communication.

Bridge

A Data Link Layer device that connects separate LAN segments, filtering and forwarding traffic based on MAC addresses to reduce collision domains.

Router

A network device that routes data packets between different networks using destination IP addresses and routing tables.

Firewall

A hardware or software component that monitors and controls incoming and outgoing network traffic based on predetermined security rules.

Server Farm

A cluster of computer servers working together to distribute workloads, dynamically allocate resources, ensure high availability, and provide redundancy.

Cloud Computing

A technology providing on-demand internet access to a shared pool of remote computing resources, such as storage, servers, and applications.

Infrastructure as a Service (IaaS)

A cloud computing model where a third-party host rents out virtualized computing resources, such as servers, storage, and networking hardware.

Platform as a Service (PaaS)

A cloud service model where a host provides hardware and software tools online for developers to build, run, and manage applications.

Software as a Service (SaaS)

A cloud delivery model where software applications are hosted by a vendor and provided to end users over the internet without local installation.

Bandwidth

The range of frequencies available for a communication method, representing the maximum potential amount of data transferable across a network per unit time.

Bit Rate

The actual rate at which bits are transferred across a data transmission medium over a given period, typically measured in bits per second ($\text{bps}$).

Buffer

A temporary storage area on a receiving device that holds downloaded streaming data before playback to ensure continuous, smooth presentation.

Real-Time Data Streaming

A streaming method where media data is delivered to client devices simultaneously as it is recorded by a camera or capture device.

Data Packet

A formatted unit of data into which larger messages are divided for network transmission, typically containing a header, payload, and trailer.

Packet Switching

A switching method where messages are broken down into individual packets that travel independently across routers and reassemble at the receiving end.

Connection-Oriented Switching

A transmission technique where a dedicated logical session is established and confirmed between endpoints before any data packets are sent.

Frame Relay

A connection-oriented packet-switching technology that divides data into frames and relies on endpoint devices for error correction to increase transmission speed.

Permanent Virtual Circuit (PVC)

A continuous logical connection in Frame Relay established to remain open long-term, even when data is not actively being exchanged.

Switched Virtual Circuit (SVC)

A temporary virtual circuit in Frame Relay that is created dynamically for a single communication session and closed once transmission ends.

Connectionless Switching

A transmission mode where individual packets (datagrams) are dispatched with no prior arrangement, no delivery guarantee, and no acknowledgment.

Circuit Switching

A switching method that sets up a dedicated, physical end-to-end path between sender and receiver that remains reserved until the connection terminates.

Message Switching

A switching method where an entire message is transferred as a complete unit from node to node across intermediate systems using a store-and-forward mechanism.

Protocol

A defined set of rules governing the format, timing, sequence, and error checking of data exchanged between devices on a network.

Transmission Control Protocol (TCP)

A connection-oriented transport protocol responsible for managing data flow, ensuring error-free delivery, packet reordering, and retransmissions.

Internet Protocol (IP)

A connectionless network-layer protocol responsible for logically addressing and routing packets across the internet to their destination.

User Datagram Protocol (UDP)

A connectionless transport protocol that transmits datagrams without flow control, error checking, or guaranteed delivery, providing faster speeds than TCP.

Internet Control Message Protocol (ICMP)

A network-layer protocol used to generate and send error messages and operational notices when problems impede packet delivery across a network.

Address Resolution Protocol (ARP)

A protocol that maps and translates a known Internet Protocol (IP) address into a physical MAC address within a local area network.

Inverse Address Resolution Protocol (IARP)

A protocol that performs the opposite function of ARP by translating a known physical MAC address into an IP address.

Dynamic Host Configuration Protocol (DHCP)

A network management protocol that automatically assigns dynamic IP addresses, subnet masks, and default gateway configurations to network devices.

Hypertext Transfer Protocol (HTTP)

An application layer protocol used for transferring web page content from a web server to a client web browser across the internet.

Hypertext Transfer Protocol Secure (HTTPS)

An extension of HTTP encrypted via TLS/SSL to authenticate websites and protect data confidentiality and integrity during web transmission.

Simple Mail Transfer Protocol (SMTP)

An application layer protocol used to transmit email messages from a client to a mail server and between different mail servers.

Post Office Protocol 3 (POP3)

An email retrieval protocol that downloads messages from a mail server to a local client device and deletes them from the server.

Internet Message Access Protocol (IMAP)

An email retrieval protocol that allows users to view and organize email messages directly on the mail server without deleting them upon download.

Telnet

A terminal emulation protocol that allows remote command-line access to another computer over the internet, transmitting all data in unencrypted plain text.

Secure Shell (SSH)

A cryptographic network protocol that provides an encrypted channel for secure remote terminal access and data communication over unsecure networks.

Transport Layer Security (TLS) / SSL

Cryptographic protocols that secure client-server communications over networks by encrypting data using both public and private keys.

Routing

The Network Layer process of calculating and choosing the best path across networks for data packets using algorithms and routing tables.

Static Routing Table

A routing table whose route entries are manually defined and configured by a network administrator, remaining fixed unless manually edited.

Dynamic Routing Table

A routing table that automatically discovers and updates network paths in real time based on active network topology and conditions.

Interior Gateway Protocol (IGP)

A category of routing protocols used by routers to exchange routing information within a single autonomous network, such as a LAN.

Border Gateway Protocol (BGP)

A specialized exterior routing protocol that manages and exchanges packet routing information between autonomous systems across the global Internet.

Open Systems Interconnection (OSI) Model Architecture

A 7-layer networking framework dividing communication into Host Layers (Application, Presentation, Session, Transport) handling data/segments, and Media Layers (Network, Data Link, Physical) handling packets, frames, and bits.

Application Layer (OSI)

Layer 7 of the OSI model, which directly interfaces with user software applications (such as email clients and web browsers) to manage communication protocols.

Presentation Layer (OSI)

Layer 6 of the OSI model, responsible for data translation, syntax formatting, encryption, decryption, compression, and decompression.

Session Layer (OSI)

Layer 5 of the OSI model, responsible for opening, managing, and terminating communication sessions between network devices.

Transport Layer (OSI)

Layer 4 of the OSI model, responsible for breaking data into segments, flow control, error checking, and ensuring end-to-end reliability.

Network Layer (OSI)

Layer 3 of the OSI model, responsible for routing data packets from network to network, logical addressing, and path determination.

Data Link Layer (OSI)

Layer 2 of the OSI model, responsible for node-to-node frame transmission within a local network, handling physical MAC addressing and error detection.

Physical Layer (OSI)

Layer 1 of the OSI model, responsible for transmitting raw binary data as bits across physical media such as cables, radio frequencies, or light.

TCP/IP Model

A four-layer networking model consisting of the Application Layer, Transport Layer, Network (Internet) Layer, and Link Layer.

Fibre Optic Cable

A high-bandwidth transmission medium composed of fine glass threads that transfers data as modulated light pulses produced by LEDs or lasers.

Coaxial Cable

A copper cable with a central conductor surrounded by insulation and a Faraday shield, designed to carry radio frequency signals with low interference.

Twisted Pair Cable

A transmission cable containing pairs of insulated copper wires twisted together to minimize crosstalk and electromagnetic interference.

Free Space Laser System

An optical communication technology that transmits high-power line-of-sight laser beams through the air between buildings or spacecraft.

Wi-Fi

A wireless networking technology using radio signals at $2.4\,\text{GHz}$ and $5\,\text{GHz}$ to connect devices to a local network via a WAP or router.

Bluetooth

A short-range, symmetrical wireless technology operating at $2.45\,\text{GHz}$ that connects up to 8 devices within $10\,\text{m}$ using paired profiles.

Infrared Transmission

A wireless communication medium utilizing infrared light over short distances ($\approx 1\,\text{m}$) in either line-of-sight mode or scatter mode.

Microwave Transmission

A line-of-sight wireless communication technology using electromagnetic waves ($300\,\text{MHz}$ to $300\,\text{GHz}$) focused between parabolic dish antennae.

Communication Satellite

An artificial orbiting body equipped with transponders and antennae to relay radio wave transmissions between Earth ground stations.

Global Positioning System (GPS)

A space-based satellite navigation system that determines a user's location on Earth by measuring radio signal travel times from orbiting satellites.

Trilateration

The mathematical positioning method used by GPS to calculate a device's 3D coordinates (latitude, longitude, altitude) using signals from 4 or more satellites.

Botnet

A network of compromised internet-connected devices secretly controlled by an unauthorized third party to execute coordinated cyberattacks.

Bot Herder

The malicious controller who remotely commands an infected botnet via internet links to harvest credentials, spread malware, or launch DoS attacks.

Backdoor

A hidden access mechanism installed in software by hackers that circumvents normal security authentication to permit unauthorized entry.

Risk Analysis

The process of identifying potential organizational disasters, evaluating vulnerable assets, assessing impacts, and developing risk control strategies.

Maximum Tolerable Downtime (MTD)

The maximum duration of time an organization can tolerate being without access to essential network systems before sustaining fatal operational damage.

Recovery Time Objective (RTO)

The estimated maximum allowable timeframe within which an organization must restore its network and resume regular business operations after a disaster.