I am looking to integrate APNS for VoIP into our app and the part that I cannot seem to find anywhere is whether or not you are supposed to pass the SIP INVITE in the payload for the APNS Push. This seems like how it would happen especially since they give you double the size of the payload for a regular push notification. I have read Apples documentation and searched to see if other people and companies that have implemented this in their VoIP apps send the SIP INVITE in the payload but cannot find an answer. Hoping someone on here will know.
No, VoIP apple push is nothing to do with SIP or SIP invite.
In reality when end-user device gets push, device needs just to register to remote server and after this to receive a call. Below you can find full steps:
1) A calling B via SIP. SIP Invite from A received by PBX/sip proxy or server.
2) PBX suspend this transaction/call and runs some custom script to send APNS push
3) Push is received by B device.
4) B device registers to PBX via SIP.
5) PBX see that now B device is available and it sends call to B via SIP protocol.