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Home » Glossary » Erlang



What is an Erlang?

Erlang is a computer language and development platform that is useful for a wide range of applications. Concurrency, distributed processing, and fault tolerance are all integrated into Erlang.

This programming language is helpful to create highly available, highly scalable soft real-time systems. Telecommunications, banking, e-commerce, digital telephony, and instant messaging are just a few industries that use it. Concurrency, distribution, and fault tolerance are all supported by Erlang’s runtime system.

The Erlang runtime system is intended for systems that exhibit the following characteristics:

  • Distributed
  • Fault-tolerant
  • Real-time soft
  • Applications that are highly available and available 24 hours a day, seven days a week
  • Hot-swapping can modify code without shutting down a system
What is an Erlang

Erlang traffic models

Several traffic models share the Erlang unit of traffic’s name. They’re formulas for estimating the number of lines you’ll need in a network or to connect to a central office. The procedure was also developed to simulate queuing scenarios, which helps estimate call center staffing requirements.

Erlang B

Erlang B is used to compute how many connections are needed based on traffic during peak hours. The Erlang B figure implies that any blocked calls are instantly freed. It is the most widely used figure in calculating telecommunications capacity.

It’s especially vital to know how busy the roads are during peak hours.

Telecommunications traffic fluctuates during the day and week, just like many other commodities.

The Erlang B figure handles peak or hectic periods and defines the degree of service necessary.

Extended Erlang B

In telecommunications, the Extended Erlang-B model (EEB) is frequently used, particularly in call centers. This erlang model enhances the well-known Erlang-B paradigm by allowing some stopped calls to be retried right away. 

This model has two iterations in math, one for offered loads and the other for blocked traffic.

There are three more variables to consider in calculating Extended Erlang B:

Traffic during peak hours. 

In terms of call traffic, the busiest hour of a telephone system’s operation.


The percentage of calls that fail due to a lack of lines


In a core group is the number of circuits.

A traffic engineering model that, like Erlang B, assumes that an offered call is immediately cleared with no queueing. 

On the other hand, Extended Erlang B believes that if a caller encounters a blockage, they will hang up and try the call again right away, with no calls being routed to more expensive routes.

Erlang C

Erlang C is a traffic modeling technique used in customer service and workforce management to determine caller wait times and predict delays. 

The number of agents providing service, the number of callers waiting, and the average amount of time it takes to handle each caller are all factors in Erlang C’s calculation.

Call center managers can improve their performance by understanding the Erlang C principles such as:

  • Recognize call volume and distribution.
  • Recognize the service level
  • Cost control is essential.
  • Make it more stable to improve the user experience.

Understanding the basics of Erlang C will benefit your company. Utilizing Erlang C can save expenses or improve your customers’ experience.

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