> Is the main purpose of traffic shaping not to relieve congestion in the > core/backhaul. To do this in the dslam would require it to know about packet > drop some way upstream from it. If the dslam is overcontended then it would > make sense to control traffic there but which is the greater problem?
fair point — but by the same token it doesn't follow necessarily to move all of the traffic management into the core if backhaul is a problem, to my uneducated eyes… depends where exactly the congestion's occurring, as you say, especially if that means you're then reliant on slightly “interesting” mechanisms in order to achieve it. > Identify the congested links and identify the traffic type then either apply > queuing downstream of it (in the case of p2p) or utilise cdn to move popular > content closer to the eyeballs. why “in the case of p2p”? what if a bunch of people are doing whacking great HTTP or RTSP transfers that's causing overcontention? CDN only helps in some scenarios, and has some “interesting” economic angles. consider... customer A has a P2P session (e.g., Spotify, or a multiplayer game) consuming a modest amount of bandwidth. customer B has an RTSP stream pulling a couple of megabits a second. in times of contention, which one would get penalised? > Or is the major slowdown in uk infrastructure happening at the edge with the > core running underutilised? AIUI (and if anyone's got information to the contrary, I'd be glad to hear it — this is a fishing expedition…), more-or-less… the edge is harder/more expensive to beef up. M.
