Networking methods
Posted in Computing, Networking conceptsModes of network operation
Networks can operate in either baseband or broadband mode.
Baseband
In the baseband mode of operation one signal is carried at any one time, the whole of the bandwidth is dedicated to a single data channel. A 1 or 0 is represented by the presence of lack of a voltage in the types of cable. Baseband signals are fast but cannot travel long distances without requiring booster equipment to amplify the signal.
Broadband
In the broadband mode of operation multiple signals are sent on a single fixed 'carrier wave'. The bandwidth is shared amongst several data channels unlike baseband mode. A 1 or 0 is represented by a variation on the carrier wave. Broadband is not only fast but can also travel further without the need for boosting.
Synchronous data transmission
Timing signals are used to synchronise the transmission of data at both the sending and receiving end using clock signals built into the device. There is no need for start and stop bits and so transmission rates are faster, however the clocks will eventually get out of sync leading to more errors.
Time-division multiplexing
A multiplexor combines multiple data streams into a signal stream of data which is then transmitted. At the receiving end a demultiplexer splits the single stream back into the separate streams which make it up.
A transmission time is split up into small 'time slots' with each data stream being assigned a time slot. The time slots are transmitted continuously regardless of whether data is being sent or not.
The line that is used to send the data must be high bandwidth, allowing thousands of streams of data to be sent at once. The speed of the line must be faster than the speed of all the streams of data combined, for example the high speed line which transmits the data of 5 combined data streams must be 5 times faster than the individual data streams.