We've added a couple of new commands to help out with diagnosing network traffic this week. By turning on net_diag_record 1, waiting a couple of minutes, then running net_diag_dump, the game will export out a text file showing you all the network traffic over that time.
It'll show you Sync Var traffic, RPCs (in and out), and per-connection traffic. It should help you to diagnose your networking bottlenecks. Quite useful for headless clients where you don't have access to the network overlay.