To access IP Camera from remote network w o Port Forwarding

Question

I want to know how is it that the IP Camera Manufactures (like D-link) having their own mobile application, able to access the cameras form remote network without port forwarding or anything. 

Can anybody tell me more about this? Thanks.

Answer 1

IP cameras send the stream to another stream engine on the cloud. And apps get data from the stream engine (even w/ authentication mechanism).
Stream Engine happens to come in between both of these elements, for data transmission.

Cheers.