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.
From secure messaging to document editing, our top free must-have apps have been rated, reviewed and named the best free Android apps of 2015. Read More »The Five Generations of Computers
Learn about each of the five generations of computers and major technology developments that have led to the current devices that we use today. Read More »Cloud Computing Market Leaders, 2015
If not for AWS, Microsoft would dominate the cloud. The race to capture market share will grow ever more fierce in the years ahead. Here's a look... Read More »
From wacky alarm clocks to lecture hall tools and after class entertainment, these Android apps are a good fit for a student's life and budget. Read More »Network Fundamentals Study Guide
A network is a group of two or more computer systems or devices, linked together to share resources, exchange files and electronic communications.... Read More »Computer Architecture Study Guide
This Webopedia study guide describes the different parts of a computer system and their relations. Read More »
Stay up to date on the latest developments in Internet terminology with a free weekly newsletter from Webopedia. Join to subscribe now.
- Watch Datamation's editor James Maguire moderate roundtable discussions with tech experts from companies such as Accenture, Dell, Blue Jeans Network, Microsoft and more »