Data Transmission and Encryption

Vocabulary flashcards covering packet structure, packet switching, error detection (CRC), and serial versus parallel data transmission methods.

Packet

A unit into which data is divided when it is sent over a network.

Packet Header

The section of a packet containing the IP destination address, IP sender address, sequence number, and packet size.

Packet Payload

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

Packet Trailer

The section of a packet containing error-checking data ($\text{CRC}$ / Cyclic Redundancy Check) and an end of packet marker.

Efficiency (Packet Use)

The advantage that large files do not clog the network, allowing multiple users to send data simultaneously.

Reliability (Packet Use)

The advantage that if one packet is lost or corrupted, only that packet is resent rather than the entire file.

Packet Switching

A method where data is split into packets sent along different routes via the best path, arriving out of order to be reassembled at the destination.

Cyclic Redundancy Check (CRC)

An error detection method where the sender calculates the number of 1-bits in the payload and stores it as a checksum in the trailer, which the receiver recalculates to detect errors.

Serial Data Transmission

A transmission method where data is sent one bit at a time over a single channel; it is reliable over long distances with fewer errors and cheaper (e.g., USB connector).

Parallel Data Transmission

A transmission method where multiple bits are sent simultaneously; it is faster over short distances (e.g., internal computer circuits) but more expensive and prone to synchronisation issues such as bit skew.

Bit Skew

A synchronisation issue that occurs during parallel data transmission.