How exactly does (or should) wifi behave when iPad or iPhone goes into sleep mode? Does it get deactivated to save battery? I know I had to install Insomnia tweak in order to keep SSH server running. But on the other hand, it doesn't make sense that you suddenly get disconnected from SIP apps, Twitter, email, Viber, messengers, etc. just because the screen went off. Do these apps have different way around using the wifi connection also in sleep mode, or what?