I disagree with you on this congestion profile thing, sky eg. dont have ip profiles. TCP is self regulating, so there would be no too much traffic going down as the speed would be managed from end to end, the only time it would do anything useful is if eg. the end user is been ddosed and the ip profile would serve to filter out all of that ddos above the profile rate. In other words unsolicited traffic. I think the ip profile is implemented as a measure to supply BTw customers (isp's) data to help them manage their networks. However since ip profiles now work properly ie. they update instantly and no longer in large steps I dont have a issue with them anymore, I just think they not technically required. When someone downloads the speed ramps up from 0 not the other way round so solicited traffic would not send too much traffic down a pipe without an ip profile. If congestion occurs, dropped packets etc. then tcp slows itself down.

Edited by Chrysalis (Thu 24-Jan-13 02:31:09)

it helps with efficient allocation of multiple virtual paths over large connections.

Sky's IP based DSLAMs do TCP/IP which works as you say, as the traffic all amalgamates at the DSLAM and is a single path backhaul and its TCP/IP all the way in a shared path. BTW and Openreach are tunnelling traffic in multiple paths to multiple ISPs so it makes sense to allocate capacity to paths that can use it - some kind of fair sharing arrangement.

I've seen a router think it has a 622M connection to something on a 6M ADSL link at the other end and the result isn't pretty.