Determining Your Peak Call Volume (VoIP Deployment)

Because of the dynamic nature of VoIP, you have to analyze your traffic much more than if you were ordering traditional telephony lines. The non-VoIP world is very logical: Your local phone carrier drops off ten phone lines to
your office, and you can then place ten calls at the same time — one per line. This setup makes life easy for the phone company because it knows up front how many calls you can possibly make, and the one-to-one ratio keeps everything neat and tidy.
VoIP changes the dynamic. You can send multiple calls at the same time over a single Internet connection. So, your VoIP provider must ensure it has sufficient bandwidth and facilities to handle all your calls. It has no idea how many calls you could potentially send it at a given time, so before you order your VoIP service, you must determine your maximum concurrent calls, meaning the maximum quantity of calls you expect to have active at the same time. This is the VoIP equivalent of ordering a certain number of lines from a traditional phone company.
You can most easily identify your maximum concurrent calls by checking your current phone bill. It should have several pages of summaries to include “peak calling hours” or “calls per hour per day.” The calling footprint for every company is different, but you probably have at least two spikes in your call volume per day. Business calling volume generally peaks when everyone is arriving in the morning between 8 a.m. and 9 a.m. (or whenever you start business). After employees deal with the morning’s follow-up calls and urgent issues, call volume tapers off until another peak occurs in the afternoon when everyone returns from lunch, and then you may have one more spike during the last hour before the office closes.
If you don’t have a helpful summary section on your invoice, isolate your sample during one of these common peak times. Because you can’t get a report that tells you exactly what you need, you have to delve in to the itemized list of your calls on your invoice. The call detail section of your invoice identifies the specifics about the individual calls in lines of data called Call Detail Records, or CDR. They usually list:
‘ Origination date ‘ Origination time
Phone number from which you placed the call
Destination phone number

Call duration Cost

If you choose the time frame from 8 a.m. to 9 a.m. for your sample, scan through your entire invoice and write down all the calls that started after 8 a.m., listing the phone number that initiated the call, as well as the start time and duration. Throw this data into a spreadsheet in case you want to manipulate the data.
After you list all the calls, take a quick look from top to bottom. Most likely, only half of your lines have a call on them at any given time. Write down a rough count of the number of calls that were active at the same time and add 30 percent more for a bit of headroom to give yourself a good starting estimate of maximum concurrent call volume.
If you really want to know the exact number of concurrent calls you have during peak times, you can take the data you collected and create a matrix for calls. Mark off a spreadsheet in one-minute increments for the entire hour, with rows representing the calls for each phone line. Draw a line on each row to identify when calls began and ended. After you plot every call on the graph for the hour, run a ruler across the page vertically and count the number of lines representing calls you cross every minute. Tally the calls at the bottom of the page and you can then see, minute by minute, the maximum number of concurrent calls placed for your office.
If you currently have a dedicated circuit or multiple phone lines, you may have your individual Call Detail Records (CDR) delivered in an electronic format on a CD-ROM. This format makes your life much easier because you can import the CDR into a database program like Microsoft Access or Microsoft Excel, then sort it by date and time to group all your calls, making this process much less time consuming than having to manually key in all of the CDR information into a database or spreadsheet.
If you run a telemarketing company, an enhanced VoIP carrier, or simply have hundreds or thousands of lines, your hardware probably can tell you your total concurrent calls.

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