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Example calculation

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How much traffic in CCS can I offer to an IP based network path whose bandwidth is 512 kbps.  I am using the G.729A codec.   I am using cRTP header compression to reduce the packet header to 2 octets and one packet is being transmitted in each direction every 30 milliseconds.  I accept that 1% of calls will be blocked.

 

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

 

•Select G.729A using the Coding algorithm drop down box.
•Select 30ms using the Packet duration drop down box.
•Select cRTP header compression (2 bytes) using the RTP header compression drop down box.
•Choose kbps as the bandwidth unit by clicking on the kbps radio button on the right side of the window.
•Choose CCS as the traffic unit by clicking on the C.C.S. radio button on the right side of the window.
•Click the Unknown radio button in the B.H.T. area to indicate that you wish to calculate the busy hour traffic.
•Enter 512 in the edit box in the Bandwidth (kbps) area.
•Enter 0.010 in the edit box in the Blocking area.
•Press the Calculate button.

 

 

After a short time, 1657.296 will be displayed in the grey edit box.  This is the result of the calculation, and shows that 1657.296 CCS of  voice traffic can be offered to a system using the selected VoIP characteristics and whose IP bandwidth is 512 kbps.  This result does not take any layer two overhead into account.