In
telecommunication
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than tha ...
, a call-second is a unit used to measure
communication
Communication (from la, communicare, meaning "to share" or "to be in relation with") is usually defined as the transmission of information. The term may also refer to the message communicated through such transmissions or the field of inqu ...
s
traffic
Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads) for travel and transportation.
Traffic laws govern and regulate traffic, while rules of the road include traffi ...
density, equivalent to one call with a duration of one second.
Traffic is measured independent of users. For example, one
user making two 75-second calls is equivalent to two users each making one 75-second call, as each case produces 150 call-seconds of traffic.
A CCS (centacall-second) is often used to describe 100 call-seconds, so 3600 call-seconds = 36 CCS = 1 call-hour.
In a communication network, a trunk (link) can carry numerous concurrent calls by means of multiplexing. Hence a particular number of call-seconds can be carried in infinitely many ways as calls are established and cleared over time. For example, one call-hour could be one call for an hour or two (possibly concurrent) calls for half an hour each. Call-seconds give a measure of the average number of concurrent calls.
Offered load In the mathematical theory of probability, offered load is a concept in queuing theory. The offered load is a measure of traffic in a queue. The offered load is given by Little's law: the arrival rate into the queue (symbolized with lambda, λ) mult ...
is defined as the traffic density per unit time, measured in
erlangs. An erlang is defined as one call-hour per hour, or 3,600 call-seconds per hour.
Hence, if one CCS is measured over a one-hour period, the offered load is 1/36 erlangs.
References
*{{FS1037C MS188
Units of measurement
Telecommunications