Editing Bit time (section)

{{Short description|Time it takes to send a bit from one network host to another}}
{{See also|Slot time}}
{{Use American English|date = March 2019}}
{{Unreferenced|date=December 2009}}

'''Bit time''' is a concept in [[computer network]]ing. It is defined as the time it takes for one bit to be ejected from a [[network interface controller]] (NIC) operating at some predefined standard speed, such as 10&nbsp;Mbit/s. The time is measured between the time the [[logical link control]] sublayer receives the instruction from the [[operating system]] until the bit actually leaves the NIC. The bit time has nothing to do with the time it takes for a bit to travel on the network medium but has to do with the internals of the NIC.

To calculate the bit time at which a NIC ejects bits, use the following:

         bit time = 1 / NIC speed

To calculate the bit time for a 10&nbsp;Mbit/s NIC, use the formula as follows:
 
         bit time = 1 / (10 * 10^6)
                  = 10^-7
                  = 100 * 10^-9
                  = 100 nanoseconds

The bit time for a 10&nbsp;Mbit/s NIC is 100&nbsp;nanoseconds. That is, a 10&nbsp;Mbit/s NIC can eject 1 bit every 0.1 microsecond (100 nanoseconds = 0.1 microseconds).

Bit time is distinctively different from [[slot time]], which is the time taken for a pulse to travel through the longest permitted length of network medium.

[[Category:Ethernet]]
[[Category:Computer network analysis]]


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