Term | Definition |
Circuit switching | Path is set up between sender and receiver and is released after transmission is complete. It cannot be used by any other traffic during that time.Data is sent in order |
Packet switching | Data (content) split into packets, which can take a different route through network and may arrive out of order - then re-assembled. Each packet carries the source and destination addresses. |
Packet information | the actual data; order number of packet; source and destination addresses; control signals; error control bits. |
Why is Packet switching preferred? | Better security. More efficient use of data lines - no waiting during gaps. Less likely to be affected by network failure. |
Half-duplex transmission | is when data can be sent in only one direction at a time. |
Full duplex | Data can be sent in both directions at once / simultaneously / at same time. |
Simplex | Data transmission is possible in one direction only. |
Serial transmission | occurs when binary digits (bits) are sent one by one along the data channel. |
Parallel transmission | occurs when a number of bits are sent simultaneously. |
Why are Network protocols necessary? | To specify data formats; to enable devices to communicate with each other. |
Data collision | occurs when two sets of data are detected on the network simultaneously. Once detected, a computer waits for a short random time then sends again. |
Multiplexing | is where several independent data sources are combined to be sent along a single route to a single destination. |
Router | is a device in a network which holds information about the addresses of computers in the network or other networks and can send data to the correct computer / network / device. |
Switching | prevents all data being sent to all parts of a network / makes efficient use of the data lines. |
Digital transmission preference | is preferred as it is less likely to suffer corruption/degradation/interference |
Protocols | are necessary to specify data formats, etc, to enable devices to communicate with each other. |
Parallel transmission | occurs when a number of bits are sent simultaneously/ sent over multiple paths / lines. |
Parallel processing | the simultaneous use of several processors/cores to perform a single task. It could be useful where an extremely large/complicated calculation is being carried out (e.g. weather forecasting |
Benefits of digital transmission | is preferred as it is less likely to suffer corruption/degradation. Can error check data. Can compress data and therefore transfer time is quicker. |