Agner Krarup Erlang

Agner Krarup Erlang ( born January 1, 1878 in Lønborg, Denmark, † February 3, 1929 in Copenhagen) was a Danish mathematician and engineer.

He was among other things to worry about queuing problems in telephony. Following the suggestion of David George Kendall the measure Erlang Agner Krarup Erlang was named after.

Erlang developed the much used in the message traffic theory Erlang distribution and thus the formulas for blocking and waiting in the loss system and response system.

For example, using the Erlang B formula, the required number of telephone lines are calculated in a call center - the Erlang -C formula can be used to estimate the required number of call center agents for a given call volume.


Agner Krarup Erlang grew up in poor circumstances in Lønborg and was as a child by his father - trained - a teacher. In 1892 he presented at the age of 14 years, his trials in Copenhagen with honors, having previously had to be obtained due to his young age a special permit. He returned to Lonborg, where he taught for two years as a teacher in his father's school. In 1896 he passed the entrance examination at the University of Copenhagen with honors and began his studies with the help of a scholarship.

He studied mathematics and science and began to care for geometric problems. After receiving his doctorate in 1901, he taught for several years as a teacher in several schools. He began to be interested in probabilities. At this time he met the chief engineer of the Copenhagen Telephone Company, which convinced him to use his skills to solve problems around the waiting time for telephone calls.

1908 Erlang was set by the telephone company and in 1909 he published his work The theory of probability and telephone conversations - the world's first detailed study of telephone traffic. In 1917 he published the Erlang distribution and thus Erlang B and Erlang C, which were quickly taken up and used by almost all telephone companies.

In his honor was called ( the predecessor of the ITU) with the name " Erlang " in 1946 at the suggestion of David George Kendall, the basic unit of traffic in a communication network by the International Consultative Committee Telephones and Telegraphs on (CCITT ).

A programming language developed at Ericsson was also named after him Erlang.