GlobalMaxTcpWindowSize

HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

Data type Range Default value
REG_DWORD 0x0 - 0x3FFFFFFF bytes (See description.)

Description

Determines the largest TCP receive window offered by the system. The receive window is the number of bytes a sender can transmit without receiving an acknowledgment. This entry override's TCP's negotiated maximum receive window size and replaces it with the value of this entry.

TCP uses a receive window that is four times the size of the maximum TCP segment size (MSS) negotiated during connection setup, up to a maximum size of 64 KB. TCP for Windows 2000 also supports windows scaling, as detailed in RFC 1323. Scaling enables TCP to provide a receive window of up to 1 GB.

For Ethernet networks, the default value of this entry is 0x4470 (17,520 or twelve 1460-byte segments.). For other networks, the default value is 0xFFFF (65535), unless 0xFFFF is larger than:

Note Image Note

This entry determines the default maximum receive window size for all interfaces. When configuring any particular interface, the value of TcpWindowSize for the interface takes precedence over the value of this entry.

Windows 2000 does not add this entry to the registry. You can add it by editing the registry or by using a program that edits the registry.

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