IGCSE Computer Science 0478 Topic 2: Data Transmission

Vocabulary flashcards generated from Topic 2: Data Transmission notes for IGCSE Computer Science 0478.

Header

The section of a data packet containing the packet number, sender's IP address, destination IP address, and error detection method.

Payload

The section of a data packet that contains the actual data being carried.

Trailer

The section of a data packet that contains an end-of-packet identifier and additional error-checking data.

Packet Data Corruption

A condition where packet data has been changed or lost, or where extra data has been gained that was not originally present.

Packet Switching

The process of breaking data into packets, routing each packet independently across a network via routers, and reassembling them in order at the destination.

Simplex Data Transmission

A directional mode where data is transmitted in one direction only (unidirectional).

Half-Duplex Data Transmission

A directional mode where data is transmitted in both directions, but not simultaneously.

Full-Duplex Data Transmission

A directional mode where data is transmitted in both directions simultaneously.

Serial Data Transmission

A transmission method where data is sent one bit at a time down a single wire.

Parallel Data Transmission

A transmission method where multiple bits are sent simultaneously across multiple wires.

Universal Serial Bus (USB)

A serial transmission connection method featuring plug-and-play automatic device detection and driver setup, as well as power delivery to peripherals.

Parity Check

An error detection check where a bit (0 or 1) is added to the most significant bit position of a byte to ensure the total count of 1s matches an agreed odd or even parity protocol.

Parity Block

A method that calculates parity both horizontally per byte and vertically per column to allow precise identification and correction of a corrupted bit.

Parity Byte

A byte sent alongside a block of data that contains the vertical parity bits calculated from each bit column in a parity block.

Checksum

An error detection technique where a mathematical algorithm calculates a value from data prior to transmission, which is recalculated by the receiver and compared to detect errors.

Echo Check

An error detection technique where a copy of received data is sent back to the sender to be compared against the original transmitted data.

Check Digit

A validation algorithm calculated value appended to data during data entry to detect input, typing, or scanning errors.

Automatic Repeat Query (ARQ)

An error control protocol combining positive acknowledgements (ACK), negative acknowledgements (NACK), and timers to handle retransmission of missing or corrupted data packets.

Plaintext

The original, readable data prior to encryption.

Ciphertext

Data that has been encrypted and rendered meaningless to unauthorized interceptors.

Decryption

The process of using a key to convert ciphertext back into readable plaintext.

Symmetric Encryption

An encryption method that uses the exact same key to both encrypt and decrypt data.

Asymmetric Encryption

An encryption method that uses a matched pair of keys: a public key for encryption and a private key for decryption.

Public Key

A key in asymmetric encryption known to everyone that is used to encrypt data.

Private Key

A key in asymmetric encryption known only to the receiver that is used to decrypt ciphertext.

Hashing Algorithm

A non-reversible mathematical algorithm that converts a given input into a fixed-length output, commonly used to create secure encryption keys.