Infinity Ward has blasted out a Tweet giving an overview of how the Call of Duty: Ghosts dedicated server systems work:
Just a reminder that we are using a hybrid system for Ghosts online play to deliver the best possible connection. So sometimes you might be on listen-servers and sometimes you might be on dedicated servers, depending on which offers the better connection. We’re making tweaks every day to improve the experience across all platforms, more updates to come. And yes, with today’s launch of Xbox One, there will be dedicated server support.
A listen server is run on the same system as the client’s game. Essentially, the Ghosts matchmaking servers will choose the player with the best connection to host the match.
The upside to this setup is that only one PC is required to send and receive data to all the other players. This is compared to the peer-to-peer system used in Modern Warfare 3, through which every player connected to the match must send and receive data from every other player.
The downside the the listen server setup, is that performance can be hamstrung by a poor residential broadband connection, and limits on the host’s computing power – hosting a match is quite CPU intensive. Then, of course, the match hinges on the host remaining active, otherwise you are waylaid by the dreaded “host migration” message.
Obviously, dedicated servers which run on specialised hardware from a data-centre with no bandwidth constraints will offer the ultimate multiplayer experience.
Unfortunately, Infinity Ward and Activision have not officially confirmed who is provided their hosting services, and the SA gaming service providers that were asked about this are not willing to share details.