What's an Erlang and How Can it Help You?

Sunday, March 15th, 2009

Agner Krarup Erlang,  was a mathematician.  Need I say more?  He derived a series of formulas to determine how many telephone operators would be required to process a given volume of calls.  And although this was done in the early 1900's his formulas still apply and can be applied to call centers today.  As the inventor, of course, you get to name your invention afer yourself, thus the Erlang was born.  An Erlang is a unit that is used to measure telephone traffic and is equal to the traffic needed to keep one phone line busy for one hour.  Enough of this dry factual data, lets talk about some real applications.

I am often asked to determine how many minutes a T1 or DS3 can handle, or how many ports a customer will need.  I would like to now share my secret for determining these numbers with you, my gentle reader.  There is a free erlang calculator, or for a small cost you can purchase and install the software on your own desktop.  The free one will handle most simple problems, and its primary limit is the number of ports or calls it can calculate.

Finding this resource is easy, simply go to www.erlang.com.   An erlang C calculator is used to calculate how many agents are needed in a call center.  An erlang B calculator is used to determine how many trunks or lines are needed in a trunk group to handle a given volume of traffic.  This is a great web site and also has calculators to determine how much bandwidth you need to handle a given number of VOIP calls using various compression techniques such as G.729. 

A couple of things to remember.  This is a mathematical model.  You  may find that your actual numbers are a little different.  For example, you may get 5000 calls in an hour, but they come in chunks of 1000 every 12 minutes.    That's going to change your experience.  This model assumes a steady flow of calls during the entire hour.  So if you are dealing with bursty traffic, you will need to adjust your use of the calculator accordingly.  If you are the corporate IT engineer and your company wants to begin using VOIP and you want to know how this could or might impact your data network, I recommend you go to this site and use the VOIP calculators.

Now, here is the cool thing about inContact.  We maintain the voice network for you.  We have thousands of TF and local DID inbound calling trunks.   We are contstantly planning and sizing our network to meet your needs.  All you need to have is enough lines to service your agents.  When calls exceed that, you can queue them up in the inContact network and not tie up your valuable phone assets.  You can even add callback features into your scripts so that callers who want to stay in queue but do not want to sit on the phone can ask the system to call them back when an agent is available.  While this still consumes a logical  inContact voice port, you do not have to pay to have the customer sitting on hold.   You can also monitor your port counts and queue sizes and generate emails for automatic notifications.  InContact is a great tool to help you squeeze the most calls out of the least amount of resources.

It does take some practice and it does require some understanding of how telephone traffic behaves, but with inContact tools and some erlang calculations, you can make sure that your customers do not get turned away.

Posted at 2009-03-15 18:03:00 in General



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