Contents.Principles of operation Like and, Compound TCP uses estimates of queuing delay as a measure of congestion; if the queuing delay is small, it assumes that no links on its path are congested, and rapidly increases its rate. However, unlike FAST and Vegas, it does not seek to maintain a constant number of packets queued.Compound TCP maintains two congestion windows: a regular window and a delay-based window. The size of the actual sliding window used is the sum of these two windows. The AIMD window is increased the same way that increases it.
jyi786[H]ardness Supreme
I'd like some of you guys to chime in on this.
In Windows 7, there is a netsh command that allows you to change the congestion provider to CTCP. Given the fact that I'm using almost enterprise grade switches and equipment at home, I want to get the full speed of the hardware I'm paying for. Using CTCP, I get almost gigabit transfer speeds. If I use the regular default OOTB settings of disabled, things get jittery. Bottom line is that I've historically done this on ALL my machines, both at work and at home, and have never had an issue with file transfer speeds. Yesterday, I installed Windows 10 on a VM for the umpteenth time to try and give it a fair shot. One of the first things I did was try and modify netsh settings, but it seems it's been deprecated. To make things even worse, I found that congestion provider settings are locked down in Windows 10 (also to a degree in Windows 8/8.1), and you cannot change the congestion provider settings. Microsoft's excuses rang hollow to me, and don't make any sense. https://social.technet.microsoft.com/Forums/windows/en-US/e3d89862-6613-4515-b504-5b111978308f/tcpip-has-chosen-to-restrict-the-congestion-window-for-several-connections-due-to-a-network?forum=w8itpronetworking http://www.neowin.net/forum/topic/1271672-set-nettcpsetting-still-incomplete-code-in-windows-10/ This is the thread where a Microsoft PM who works in the Core Networking team made some comments that didn't make sense to me. https://social.technet.microsoft.com/Forums/windows/en-US/f55027d7-f4cf-4681-96b5-b530c9dab7e0/cant-set-netsh-int-tcp-set-supplemental?forum=w8itpronetworking Here's a bunch of forum posts which clearly show the effect of enabling ECN and CTCP on a Windows 8 machine. http://www.networkedmediatank.com/showthread.php?tid=63992&pid=588255 This is kind of a deal breaker to me. Yes, I have noticed slower transfer speeds when I tried Windows 10 before, but I haven't run any statistical benchmarks or anything, since I wasn't seriously considering keeping the OS. Any of you [H] networking gurus have thoughts to contribute to this?
If the delay is small, the delay-based window increases rapidly to improve the utilisation of the network. Once queuing is experienced, the delay window gradually decreases to compensate for the increase in the AIMD window.
The aim is to keep their sum approximately constant, at what the algorithm estimates is the path's. In particular, when queuing is detected, the delay-based window is reduced by the estimated queue size to avoid the problem of 'persistent congestion' reported for FAST and Vegas. Thus, unlike and its precursor, Compound TCP can reduce its window in response to delay. This increases its fairness to Reno.
The use of netsh int tcp set global congestionprovider=ctcp has been depreciated. In order to set or change the congestionprovider the following command must be used: set-nettcpsetting -CongestionProvider CTCP However, CTCP is the default on windows 8 and later. Changing the setting does not seem to work on Windows 10.
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