How to Determine the Correct Number of Lines, Trunks and Channels for Your Telecom Systems

As your company or organization grows, chances are good that the need for increased capacity for carrying telephone traffic will increase.

In fact, to provide that fewer and fewer callers ever receive a busy signal, the number of facilities for carrying those calls must be increased disproportionately. But how do you know just what configuration you will need to handle the increased traffic in an efficient manner?

Introducing

is a powerful computer program that we at TelCon Associates have developed for use with our clients to help them determine the correct amount of “servers” (lines, trunks, circuits, etc.) for their companies. It is a program that we developed and, frankly, we are quite proud of it.

In a moment, we will show you where to go to analyze your traffic for free using

Traffic Concepts Explained

Efficient telecommunications requires enough lines to carry desired calls/sessions. The telecommunications industry has generally planned for enough lines to provide a P.01 grade of service (GOS), which means that one caller out of 100 will be blocked (receive a busy signal) on the first call attempt during the busiest hour (within a specified period, usually a day).

Of course, with a P.01 GOS far fewer busy signals will be encountered during less-busy hours. P.01 GOS is ideal for many circumstances. But if more than 1% busy signals is acceptable, fewer lines will be needed. And assurance of fewer busy signals will require more lines.

How Does Work?

uses queuing theory, a statistical method for predicting service levels within a system that provides a service of random duration to users demanding service at random times.

The problem with traffic formulas and tables found in books is they require that the total amount of offered traffic be known and expressed in Erlangs in order to calculate the grade of service for various numbers of servers (e.g., lines, trunks/channels).

However, in most real-world situations, available data usually describe carried, not offered traffic, and are rarely expressed in Erlangs.

overcomes two of these deficiencies by calculating accurately using carried traffic and busy-hour hours (Erlangs), minutes or CCS (100-second units) as direct inputs. And it represents GOS as a percentage, rather than a decimal (i.e., P.0100 = 1.00%). (The user must determine the busy-hour hours, minutes, or CCS to be entered.)

How to Use

First, CLICK HERE to open in your browser. Before you begin entering data, become familiar with these terms:

  • Blocked Calls/Overflow - attempted (offered) calling that received a busy signal/condition

  • Calls Cleared - blocked calling that is automatically routed to other line/trunks/channels, or from callers who immediately use other means to make the call.

  • Carried Traffic - the volume of calling completed between calling and called parties within a given period of time.

  • CCS - 100 call seconds; one hour = 36 CCS

  • Erlang B - the calculation model used in , is ideal for use with situations wherein calls will be “cleared,” which includes most outgoing calling.

  • Erlangs - total traffic, in hours, during the busiest hour.

  • Grade Of Service - the percentage of offered calling that will be expected to receive a busy signal/condition on the first call attempt during the busiest hour (within a specified period, usually a day).

  • Offered Traffic - the volume of calling placed within a given period, including calls that received a busy signal/condition.

  • Servers - telecommunications lines, trunks, channels, etc.

Now Enter Data Into

With the program opened in your browser, select (click on) busy-hour units of calling/traffic - hours, minutes or CCS and follow these simple steps:

Two data factors must be entered; enter corresponding numbers (e.g., 1 and 3 indicates that you will enter the number of lines/trunks and the amount of carried traffic.

Click on “Calculate.” Calculated values for the other three factors will appear.
If additional calculations are desired, repeat steps 2-4. It is not necessary to clear values before entering numbers for a new calculation.

Values from any calculation can be saved for viewing with new calculations by clicking on “Save Values” before starting a new round of data entry.
All entries and values can be cleared by clicking on “Clear Values.”

Get started using Traf