Inside an operating system, it costs nothing more than a tiny bit of memory to have an "open" TCP link. The CPU doesn't have to do anything until a packet actually comes in. It's really just a pathway, knowing which app is supposed to get the packet. If the app is written properly, it will use *zero* CPU until something happens.
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Thank you very much! I like to believe I am technically inclined, but really I only have an elementary understanding of this stuff, particularly with telecom.
Anyways, I guess I always had thought that cellphones had a data/IP "connection" that could be toggled "on" and "off", so I couldn't see how a phone could remain dormant until a notification was "pushed" to it outside of using the SMS "heartbeat" signal. But as you said, IP "connections" can sit there idling waiting for packets without using the CPU. I guess my mind is stuck in the circuit switched paradigm.
I'm trying to sort this out in my brain.. So when an iPhone user opens Safari, the OSX networking stack generates the TCP/IP packets to send to the web server and then passes them to the baseband. The baseband then encapsulates these packets inside some type of EDGE/UMTS transport mechanism and sends that to the tower.. The tower switch then unpacks the TCP/IP packets and forwards them along a backhaul to some main AT&T switch where they get sent to the web server... ???
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Ahh, well, what do you mean by "active"?
Inside an operating system, it costs nothing more than a tiny bit of memory to have an "open" TCP link. The CPU doesn't have to do anything until a packet actually comes in. It's really just a pathway, knowing which app is supposed to get the packet. If the app is written properly, it will use *zero* CPU until something happens.
...
Thank you very much! I like to believe I am technically inclined, but really I only have an elementary understanding of this stuff, particularly with telecom.
Anyways, I guess I always had thought that cellphones had a data/IP "connection" that could be toggled "on" and "off", so I couldn't see how a phone could remain dormant until a notification was "pushed" to it outside of using the SMS "heartbeat" signal. But as you said, IP "connections" can sit there idling waiting for packets without using the CPU. I guess my mind is stuck in the circuit switched paradigm.
I'm trying to sort this out in my brain.. So when an iPhone user opens Safari, the OSX networking stack generates the TCP/IP packets to send to the web server and then passes them to the baseband. The baseband then encapsulates these packets inside some type of EDGE/UMTS transport mechanism and sends that to the tower.. The tower switch then unpacks the TCP/IP packets and forwards them along a backhaul to some main AT&T switch where they get sent to the web server... ???