VoIP on mobiles, how do the networks know?
This is a geeky post, if you normally read my other stuff.. i’d just skip over this one…
I’ve seen a couple of places now, where people are asking questions about using VoIP via mobile data connections, for example:
It worries me that on soooo many internet forums with self styled mobile gurus, no-one seems to know the answer… which is (to use an american-ism) internet traffic 101! Its basic net knowledge for any decent geek. (no diss intended to mr P!)
I’m going to try n make this as un-geeky as possible and acknowledge that, yes, if you’re an uber-geek I’m not using all the correct definitions of words or explanations of the 7 layer OSI model… purely to try n make it easier to understand.
Internet traffic has layers, at the bottom you have physical connection (a cable/wifi/mobile data – 3G etc) then you have TCP/IP which tells this packet of data to go to this place and then application layers on top, these layers all surround the actual data and tell it how its used because, in the end, it’s all 1’s n 0’s kids!
(read about the OSI model on wikipedia if you really want to know more)
By examining each packet that goes through their network gateways etc, they can see what service you’re using… FTP/http/SIP/VoIP etc.
This is how mobile networks can stop you using “all you can eat” unlimited data tarriffs for VoIP to get free calls, for me, I only use Fring via WiFi on my Nokia N95, pretty much everytime I’ve wanted to use it theres been a wifi network I can use (ahem.. or borrow ;-)).