Or you can skip to the end to realize that the whole point is:
If you don't have resources to test your game, you will waste shit ton of bandwidth.
its more about metrics. john carmack mentioned something similar last year in his interview after idtech5/rage release.
basically you can be an expert in the respective field and try to implement all kinds of solutions to (code errors, network lag, etc) but unless you have hard numbers to break down where the real issue is, you are shooting in the dark and will likely cause more problems than you solve.
from halo3 to halo reach they cut down the relevant packet stream to 20% of what halo3 was using because they could see which items/states were taking up too much priority or data.
the bigger takeaway from the presenter was that bungi is working on a massive multiplayer action game. assuming they can take the networking knowledge gained from peer to peer hosting and use it with dedicated servers, their next game should be very impressive.