Unit 2 - Data transmission (IGCSE)

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 the purpose of a packet trailer?

Back

Indicates the end of the data packet and includes a 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 purpose of a hop number in a data packet header?

Back

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