Inquiry Regarding Parallel Call Functionality with SIPSorcery

[gerbuchner]

I am currently working on developing a dialer application using SIPSorcery. The goal is to run the dialer on a Windows PC and have it initiate multiple simultaneous outbound calls. For this purpose, several SIP user accounts are available in our PBX system. When a call is successfully answered by the remote party, it should then be forwarded to an internal extension.

At this point, I am able to establish individual calls successfully. However, I am encountering difficulties when trying to initiate multiple calls in parallel. The call initiation method simply returns false without any error message, which makes debugging challenging. I suspect the issue may be related to the use of VoIPMediaSession.

I am currently creating separate SIPTransport instances for each user, each bound to a different local port.

Could you please advise if there is a supported way to initiate multiple simultaneous calls using SIPSorcery? Any guidance or best practices you could share would be greatly appreciated.

Best regards,
Gerhard

[sipsorcery]

The SIPTransport can handle as many calls as you want. The original use case for this library was to act as a statless SIP Proxy and the SIPTransport and 'SIPChannel` classes are amongst the mast mature.

It's recommended to use a single SIPTransport instance for your application and share it amongst the user agents. That may require some work as user agents typically don't know about each other. Take a look at the isTransportExclusive on the SIPUserAgent class for an approach.

The RTPSession, VoIPMediaSession 100% cannot be sharedand you need a new instnace per call. Depedning on your call volume and what you are doing with the audio/video side of things may not scale that well. While the SIP side of this library was optimised for server applications the RTP and media handling side has not been.