Can someone explain why P2P games utilize servers?

[DPatel]

I was always under the assumption that anything utilizing a P2P connect (such as a console game), would only require two consoles connected to the internet to function. One would act as the host and one as the client. But I've seen some articles, such as these:
http://kotaku.com/5402535/infinity-...-ps3-online-problems-server-not-patch-related

which seem to contradict that. I am almost certain MW2 does not utilize dedicated servers, so, I'm assuming it utilizes P2P connections, yet they are complaining about server issues. Can someone please clarify why a non-dedicated server game would even need a server? Thanks in advance.

 

[upnorthsox]

Matchmaking, stats, lobby...........basically everything that happens before and after the match.

 

[DPatel]

Thanks so much. That makes sense. Pretty crazy to see servers having issues for only being utilized for those purposes. Unless those things are much more harder on the server than I think.

 

[Grall]

I believe you also need a central server to initiate an IP connection through a firewalled/NAT:ing router, like many/most people have hooked up to their broadband feeds...