Difference in 343 servers?

Okay so my question is what is the difference between 343 servers and bungie’s servers. I know Bungie had dedicated servers and 343 uses host servers. I’m not going to be another one of those people that come one here and complains and whines about everything about Halo 4 because I generally enjoy playing the game. But the Lag is something that gets me every 3 out of 10 games. I have 50mbps dl and 6 mbps but yet I lag. I never lagged in 2 or 3. Soooo this brings me to my point can someone give me a breakdown of the server differences. Does dedicated servers basically mean that Bungie hosted the game instead of a host? Do you see 343 going back to dedicated servers?