Unit II - Data transmission (IGCSE) -key terms

Front

What is a data packet?

Back

A small part of a message/data that is transmitted over a network; after transmission, all the data packets are reassembled to form the original message/data.

Front

What does a packet header contain?

Back

The IP addresses of the sender and receiver, and includes the packet number which allows reassembly of the data packets.

Front

What is a packet trailer?

Back

The part of a data packet that indicates the end of the data packet and includes the cyclic redundancy check (CRC) for error checking.

Front

What is cyclic redundancy check (CRC)?

Back

An error checking method in which all the 1-bits in the data packet payload are added, and the total is stored in the packet trailer; the same calculation is repeated at the receiving station.

Front

What is the payload in a data packet?

Back

The actual data being carried in a data packet.

Front

What is a node in a network?

Back

Stages in a network that can receive and transmit data packets; routers are nodes in communication networks.

Front

What is packet switching?

Back

A method of transmission in which a message is broken into many data packets which can then be sent along pathways independently of each other.

Front

What is a router?

Back

A device that enables data packets to be moved between different networks, for example, to join a LAN to a WAN.

Front

What is real-time streaming?

Back

The transmission of data over a network for live events where the data is sent as soon as it is received or generated.

Front

What is the hop number in a data packet header?

Back

A number used to stop data packets that never reach their destination from clogging up the data paths/routes.