To ascertain the bandwidth required, you need to perform the following simple calculation using your desired codec:
Concurrent calls x Codec kbps = bandwidth
| G711* | Highest quality codec | 100kb per second |
| G711 Ulaw** | Highest quality codec | 100kb per second |
| G722 | HD codec | 60kb per second |
| G729 | Lowest quality codec | 40kb per second |
*A-Law is mostly used in Europe (uses a 12 bit rate compression)
**U-Law is mostly used in USA/Japan (uses a different compression method to force it at 13 bits)
Packetisation delay is the time taken to fill a packet payload with encoded/compressed speech. This delay is a function of the sample block size required by the vocoder and the number of blocks placed in a single frame. Packetisation delay can also be called Accumulation delay, as the voice samples accumulate in a buffer before they are released. Currently the most common sample period is 20 ms, although customers may opt for 10 ms, which introduces less latency but at the expense of greater bandwidth. Only one sample period (10 ms or 20ms) may be provided by a customer.
Change Codec & Packetisation #
Step 1
From the Gamma Portal, go to “Provisioning and Service Management”, “Voice Connectivity”, “Gamma SIP Trunks” and “Service Management”.
If you don’t have this option contact your Portal Administrator (Help and Support and Portal Administrators) or contact your Internal Account Manager.
Step 2
Select the account that has the endpoint you wish to edit change the codec for and click “View”.
Step 3
Click on the “Update Codec Details” option in the Actions drop-down and click Continue
Step 4
