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Example calculation

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How much bandwidth in Mbps should I provide through an IP based network to carry 600 voice paths?  I am using the G.729A codec.  I am using cRTP header compression to reduce the packet header to 4 octets and one packet is being transmitted in each direction every 20 milliseconds.


To find out the answer to this question, follow these steps:


Select the Lines to IP Bandwidth Calculator using the relevant tab at the top of the window.
Select G.729A using the Coding algorithm drop down box.
Select 20ms using the Packet duration drop down box.
Select cRTP header compression (4 bytes) using the RTP header compression drop down box.
Choose Mbps as the bandwidth unit by clicking on the Mbps radio button on the right side of the window.
Click the Unknown radio button in the Bandwidth (Mbps) area to indicate that you wish to calculate the bandwidth.
Enter 600 in the edit box in the Voice paths (lines) area.
Press the Calculate button.



After a short time, 5.760 will be displayed in the grey edit box.  This is the result of the calculation, and shows that 5.76 Mbps is required to transmit 600 voice channels through an IP based network using the selected VoIP characteristics.  This result does not take any layer two overhead into account.