Description
During the call setup with VoLTE/VoWiFi with EVS voice codec the bandwidth is negotiated.
How can the bandwidth be setup and how will it be shown in the CMW user interface?
EVS Bandwidth Indicator VoLTE and VoWiFi call on CMW500/CMW290 user interface
Resolution
You find the settings in the "Virtual Subscriber Configuration".
Bandwidth can be setup to a dedicated bandwidth e.g. "swb" or a bandwidth range e.g. "nb-swb".
Keep in mind the EVS bandwidth indicator always shows the bandwidth that the IMS server and the terminal have agreed during voice call setup in the SIP signaling.
- For Mobile Terminated Calls (call setup from the CMW), this means that the bandwidths are negotiated during the call setup as set in the Virtual Subscriber e.g. "swb".
- If the device can handle the codec/bandwidth (EVS "swb") offered by the CMW, also confirms this, the indication "swb" is displayed in this case.
- In the case of a Mobile Originated Call (call set-up from the end device), the end device offers the supported codecs/bandwidths and almost all end devices offer EVS with "nb-swb".
- Therefore "nb-swb" is then displayed and not "swb" - so it is not a display derived from the RTP stream of the language packs.
- If there are no restrictions (very poor reception, high bit error rate), you can assume that the bandwidth for swb is also used with the indication "nb-swb".
- The "Force Codec for MO Calls" setting can only affect whether the AMR or EVS codec is negotiated, but cannot force a specific bandwidth.
