Unit 06 Data Communication and Computer Networking Technologies Flashcards

A comprehensive set of vocabulary flashcards covering the concepts, components, and protocols of data communication and computer networking as presented in the lecture notes.

Data communication

The process of transmitting data between two or more communicating devices over some transmission media.

Computer networking

The process of establishing connections between computing devices.

Message

The information to be communicated by the sender to the receiver.

Sender

Also known as the Transmitter or Source, this is any device capable of sending data.

Receiver

Also known as the Destination, this is the device that the sender wants to communicate data to.

Communication Medium

Also known as the Transmission System, it is the path by which the message travels from sender to receiver.

Protocol

A set of rules defining the order and format of data exchanged between networking devices, including rules for syntax, semantics, synchronization, and error recovery.

Computer Network

Two or more computers linked together using a communication medium to share resources.

Signal

An electronic voltage or current which varies with time, used to transfer data from one end to another.

Analog signal

Signals in continuous wave form represented by continuous electromagnetic waves, such as sound, light, and temperature.

Digital signal

Signals that use discrete values, specifically binary values $1$ and $0$, to represent information.

Amplitude

The height of a wave measured in meters.

Frequency

The number of complete waves that pass a point in one Second, measured in Hertz ($Hz$).

Wavelength

The distance between adjacent crests, measured in meters.

Phase

A position of a point in time (instant) on a waveform cycle.

Propagation speed

The speed at which a wave propagates through a given medium.

Transmission media

A communication channel in the Physical layer of the OSI model that carries information from the sender to the receiver via electromagnetic signals.

Guided / Wired Media

Physical wire mediums that guide data transfer from one point to another to reduce data impairment.

Twisted Pair Cable

Pairs of twisted copper wire used for data transmission, available as Unshielded (UTP) or Shielded (STP).

Unshielded Twisted Pair (UTP)

Flexible and low-priced twisted copper wire pairs used for telephone connections, suitable for distances up to $100\,meters$.

Shielded Twisted Pair (STP)

A better quality, secure, but more expensive data transmission medium compared to UTP.

Coaxial Cable

An electronic cable pair consisting of a central cable and an outer braided copper net separated by a plastic shield, used for TV antennas and CCTV.

Fiber Optics cable

Cables consisting of a glass tube core and glass cladding that transmit data by reflecting light.

Unguided / Wireless Media

Media where data is transmitted as signals through the air without using a physical medium.

Radio waves

Wireless transmission used for mobile phone signals, AM/FM radio, Wi-Fi, and Bluetooth.

Micro Waves

Signals that travel in a straight line between transmission centers, used in satellite communication with satellites stationed $36,000\,km$ above the earth.

Infrared

Wireless communication used for short distances with speeds less than $10\,mbps$, such as TV remotes and wireless keyboards.

Latency

The amount of time it takes for a unit of data to travel from one point to another, usually measured in milliseconds.

Bandwidth

A range of frequencies measured in Hertz ($Hz$).

Transmission Impairment

The degradation of signal quality as it passes through transmission media.

Attenuation

The loss of energy in a signal as its strength decreases due to resistance over distance; fixed using amplifiers.

Distortion

A change in a signal's original shape caused by characteristics of the medium like capacitance and inductance.

Noise

Any unwanted or random signal that mixes with the original signal.

Induced noise

Noise coming from devices like motors and appliances where the transmission medium acts as a receiver.

Thermal noise

Signal interference caused by the movement of electrons in a wire.

Crosstalk noise

Interference that happens when signals from one wire interfere with another wire.

Impulse noise

High-energy signals from sources like lightning or power lines.

Modulation

The technique of modifying characteristics like frequency, amplitude, or phase of a carrier signal by attaching a modulating signal to it.

Amplitude Modulation (AM)

An analog modulation technique where the amplitude of the carrier signal varies while frequency and phase remain unchanged.

Frequency Modulation (FM)

An analog modulation technique where the carrier signal frequency changes according to the modulating signal.

Phase Modulation (PM)

An analog modulation technique where the phase of a carrier signal is modified to reflect changes in the voltage of an analog data signal.

Amplitude Shift Keying (ASK)

A digital-to-analog conversion technique where the amplitude of an analog carrier signal represents binary data (high for $1$, low/zero for $0$).

Frequency Shift Keying (FSK)

A digital-to-analog conversion technique where different frequencies of an analog carrier signal represent binary $1$ and $0$.

Phase Shift Keying (PSK)

A digital-to-analog conversion technique where different phases of an analog carrier signal represent binary $1$ and $0$.

Pulse Code Modulation (PCM)

A method used to convert analog data into digital binary signals involving three steps: Sampling → Quantizing → Encoding.

Synchronization

The process of ensuring data is sent and received correctly between devices, often using a clock signal for timing.

Encoding

The conversion of data into digital signals.

Non-return to Zero Level (NRZ-L)

An encoding scheme using two constant voltages to represent $0$ and $1$ bits.

Non-return to Zero Inverted (NRZ-I)

An encoding scheme where a $1$ is represented by a transition of the physical level and a $0$ has no transition.

Manchester encoding

An encoding scheme where voltage changes from low to high or high to low in the middle of the signal.

Error detection

The process of identifying that a data bit has been altered during transmission.

Parity Check

A simple error detection mechanism where an extra bit is added so the number of $1$s is either even (Even Parity) or odd (Odd Parity).

PSTN (Public Switched Telephone Network)

The world's public telecommunication system connecting various networks through switching centers.

Network topology

The layout or pattern of connections in a computer network.

Star Topology

A layout where every device is directly connected to a central hub or switch.

Ring Topology

A closed loop layout where each device is connected to two neighbors and data often travels via a token-passing mechanism.

Bus Topology

A layout where all devices are connected to a single main cable called the backbone, which has terminators at both ends.

Tree Topology

A hierarchical structure combining Bus and Star topologies, with computers connected like branches.

Mesh Topology

A layout where each device is connected directly to one or more others, providing high reliability through multiple paths.

Hybrid topology

A network structure that combines two or more different topology types.

Simplex

A data transmission mode where data can only flow in one direction.

Half-Duplex

A data transmission mode where data can flow in both directions, but not at the same time.

Full-Duplex

A data transmission mode where data can flow in both directions simultaneously.

Unicast

One-to-one communication where data is sent from one computer to another using a unique recipient address.

Multicast

One-to-many communication where data is sent from one device to a specific subset of devices on a network.

Broadcast

One-to-all communication where a message is sent to all recipients on a network.

Modem

A device that performs Modulation and Demodulation by converting digital signals to analog and vice versa for internet connectivity.

Repeater

A device that amplifies and retransmits weakened signals to extend the range of a network.

Network Interface Card (NIC)

A hardware component with a unique MAC address that allows a computer to connect to a wired or wireless network.

Hub

A basic networking device that connects multiple devices but broadcasts data to all ports regardless of the intended recipient.

Switch

An efficient device that connects multiple devices and directs data only to the specific intended device by learning which devices are on which ports.

Bridge

A device that connects separate networks to function as a single one while dividing them into manageable parts to reduce traffic.

Router

A device that connects different networks and uses routing tables to determine the best path for data using IP addresses.

Gateway

A device or software that acts as a translator between two different networks using different protocols and provides security features.

PAN (Personal Area Network)

A small network for personal use within about $10\,meters$, such as Bluetooth connections.

LAN (Local Area Network)

A network covering a limited area like a room or building for connecting computers and printers.

MAN (Metropolitan Area Network)

A network connecting multiple LANs across a city, typically ranging from $5$ to $50\,km$.

WAN (Wide Area Network)

A network spanning large geographic areas like countries or the whole world (e.g., the Internet).

Multiple Access Protocols

Rules used to manage communication and avoid collisions when multiple devices share the same channel.

FDMA (Frequency Division Multiple Access)

A channelization protocol that divides bandwidth into different frequency bands for each station.

TDMA (Time Division Multiple Access)

A channelization protocol that assigns specific time slots to different stations using the same frequency.

CDMA (Code Division Multiple Access)

A channelization protocol that uses unique codes for each station to transmit simultaneously over the same frequency.

Pure ALOHA

A protocol where stations can send data at any time and wait for a random back-off if no acknowledgment (ACK) is received.

Slotted ALOHA

A protocol where time is divided into fixed slots and stations can only send data at the beginning of a slot.

CSMA (Carrier Sense Multiple Access)

A protocol where stations sense the channel to check if it is idle before transmitting data.

CSMA/CD (Collision Detection)

A protocol where stations monitor the channel for collisions and stop transmitting immediately if one is detected.

CSMA/CA (Collision Avoidance)

A protocol where stations sense the channel and wait random back-off times specifically to avoid collisions from occurring.

IP Address

A unique identifier assigned to every node in a network for location and communication.

IPv4

An Internet Protocol version using $32$-bit addresses written in dotted decimal notation.

IPv6

A newer Internet Protocol version using $128$-bit addresses written as eight groups of four hexadecimal digits.

Sub-netting

A technique used to divide a network into smaller sub-networks to prevent the depletion of IP addresses.

CIDR (Classless Inter Domain Routing)

An addressing scheme that allows for flexible allocation of IP addresses and helps reduce the size of routing tables.

MAC address

A unique $48$-bit ($6\,bytes$) identifier assigned to a network interface, used at the Data Link layer.

Client-Server architecture

A model where client computers request services or data, and powerful server computers process and fulfill those requests.

File Server

A server that manages file storage, sharing, and access control centrally using protocols like FTP.

Proxy Server

A server that acts as an intermediary, improving speed via caching and hiding a user's real IP address.

Web Server

A system that serves web content to clients using protocols like HTTP and HTTPS.

HTTP (Hypertext Transfer Protocol)

The main protocol used to transfer web data, typically running on port $80$.

SSH (Secure Shell)

A protocol used to securely connect to and manage remote computers using encryption.

SMTP (Simple Mail Transfer Protocol)

A protocol used to send emails from clients to servers and between servers.