Our business works on a call & communication inside a LAN without an internet connection solution with a signaling server placed inside the Local Area Network.
How can we make and keep a socket open on an iOS device to do signaling operations between the app and the server to get voice calls and messages in the organization.
In this case I think there is no connection to Apple's PushKit to activate the CallKit and open the app to Ring for an incoming call.
Is there an alternative to do so, like having a Local Push server (instead of apns) defined for organization's iOS devices with a certificate or profile to be used by that iOS devices to get push notifications from or having a single socket from the iOS app connected to a signaling server and keeping it connected (like background voip that is deprecated in iOS 10) to somehow with a Local notification inform the callee with an incoming call.
If there can be a way or many ways to do so please inform us with needed steps or alternatives.
Thanks in advance