erlangA unit of measurement of traffic density in a telecommunications system. The erlang describes the total traffic volume of one hour, or 3600 seconds.
For example, 60 calls in one hour, each lasting 5 minutes, results in the following number of erlangs:
minutes of traffic in the hour = number of calls x duration
minutes of traffic in the hour = 60 x 5
minutes if traffic in the hour = 300
hours of traffic in the hour = 300/60
hours of traffic in the hour = 5
traffic figure = 5 erlangs
Network designers use the erlang to understand traffic patterns within a voice network and use the figures to determine how many lines are required between a telephone system and a central office or between network locations.
Erlang calculations are further broken down as follows:
- Erlang B -- the most commonly used traffic model. Erlang B is used to work out how many lines are required if the traffic figure during the busiest hour is known. This model assumes that all blocked calls are cleared immediately.
- Extended Erlang B -- similar to Erlang B, this model can be used to factor in the number of calls that are blocked and immediately tried again.
- Erlang C -- this model assumes that all blocked calls are queued in the system until they can be handled. Call centers can use this calculation to determine how many call agents to staff, based on the number of calls per hour, the average duration of class and the amount of time calls are left in the queue.
Stay up to date on the latest developments in Internet terminology with a free weekly newsletter from Webopedia. Join to subscribe now.
The following facts and statistics capture the changing landscape of cloud computing and how service providers and customers are keeping up with... Read More »Facts about Computer Science: Education and Jobs
The following computer science facts and statistics provide a quick introduction to the changing trends in education and related careers. Read More »Texting & Chat Abbreviations
From A3 to ZZZ this guide lists 1,500 text message and online chat abbreviations to help you translate and understand today's texting lingo. Read More »
Learn about each of the five generations of computers and major technology developments that have led to the computing devices that we use... Read More »Computer Architecture Study Guide
Computer architecture provides an introduction to system design basics for most computer science students. Read More »Network Fundamentals Study Guide
Networking fundamentals teaches the building blocks of modern network design. Learn different types of networks, concepts, architecture and... Read More »