What kind of online networking does the PC use?

I've switched from the Xbox 360 version to the PC and while the PC feels and looks so much better, the online connectivity is absolutely horrible!

Everyone's lagging, no one has a full green bar, People start a second before others, you can lag through people & the connection randomly drops out and you're left there by yourself.

What does the PC use? Servers or hosting like the console versions? I have no trouble with the Xbox version, PC is awful for online play!