This topic is a how to.
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The Explicit Congestion Notification (ECN) is an extension to the Internet Protocol (IP) and to the Transmission Control Protocol (TCP) defined in the RFC 3168.
ECN allows end-to-end notification of network congestion without dropping packets. ECN is an optional feature that is only used when both endpoints support it and are willing to use it; it is only effective when supported by the underlying network.

Windows versions since Windows Server 2008 and Windows Vista support ECN for TCP, but it is disabled by default; to turn on ECN support, open an administrative command prompt and run the command

netsh int tcp set global ecncapability=enabled

To turn off ECN support run the command

netsh int tcp set global ecncapability=disabled

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