Provider Nexmo

nexmo.com

Notes

From: Aviv Shaham <aviv@sent.com>
Date: Fri, 07 Nov 2014 09:18:23 -0700

Nexmo doesn't seem to handle it well if your first specified codec is L16. Try to set absolute_codec_string to PCMU and see if that helps.

Also note that there is no need to include custom SIP headers such as api_key, api_secret, and answer_url when you make an outbound call.

Since you mentioned also needing inbound - keep in mind that when you use Nexmo's built-in "Forward to SIP" setting for each number in the dashboard, the dialed number will not be passed as a SIP variable and you have no way of knowing it once you receive the SIP invite. One way to get around this is to have your application buy & update numbers via the Nexmo API and set a custom SIP address per Nexmo DID, for example: nexmo_12121115555@your-server.com and then have a dialplan such as:

<extension name="IncomingNexmo">
   <condition field="destination_number" expression="^nexmo_(\d+)$">
      <action application="info"/>
      <action application="set" data="nexmo_forwarded_for=$1"/>
      <action application="lua" data="nexmo_handler.lua"/>
   </condition>
</extension>

The nexmo_forwarded_for session variable will now expose to you the dialed Nexmo phone number allowing your application or XML dialplan to use it.