I dont' know what's behind the scenes but from what I've seen
- most of the DC comes on: login, map loading, auction house, game creation, access to them map
- I frequently got ton of DCs before being able to start a game but when I'm in game I get no DC for 15 or 30 mins in a row
Imo its not a connection problem it's a DB problem. I bet most of the in game activity (pve fight, pvp fight, etc.) don't require heavy access to DB, while of other ones do. If access to DB fails (because a limit to concurrent connection, dead lock or other stuff) a network request fails and that's prolly treated as DC by the client
this just to try to help please dont read it wrong
cheers