I am writing to seek your guidance on an issue that we are currently facing in integrating 3rd party SIP agents with our Twilio SIP domains. We are trying to understand how we can facilitate any 3rd party agents to successfully transfer SIP headers to our SIP domains.
In our efforts to solve the issue, we have been experimenting with the Call Control Configuration feature under Twilio SIP domains. However, we have noticed that the configuration only appears to be triggered when calls are made from SIP endpoints registered within the same domain, and not from the 3rd party SIP endpoints.
Given the scope and the specificity of the problem, we're at a point where we could greatly benefit from your insight. Are there specific settings or techniques we need to adopt in order to trigger the Call Control Configuration for 3rd party SIP endpoints? If not, what alternatives would you suggest for enabling SIP header transfer from 3rd party SIP agents to our SIP domains?
We would highly appreciate any guidance or documentation you could share on this matter. This integration is an important part of our operation and we are eager to resolve this at the earliest to ensure a smooth workflow.