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        W2K registry Tweaks to increase cable modem and dsl speed

Section(s): Network
Published on Apr 20, 2004.
Last Modified on Apr 20, 2004.
Last Modified by Wayne Maples.
Rated 4.2 out of 5 based on 25 votes.

To boost network performance, add the following values to the Parameters Key:

Hive: HKEY_LOCAL_MACHINE
Key: SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

Name: DefaultTTL
Type: REG_DWORD
Value: 128 default=32
default time to live (TTL) for TCP/IP packets

Name: EnablePMTUBHDetect
Type: REG_DWORD
Value: 0 default=0
whether the stack will attempt to detect Maximum Transmission Unit routers that do not send back ICMP fragmentation-needed messages.

Name: EnablePMTUDiscovery
Type: REG_DWORD
Value: 1 default=1
Specifies whether the TCP/IP stack will attempt to perform path MTU discovery as specified in RFC 1191.

Name: SackOpts
Type: REG_DWORD
Value: 1 default=0
Enables support for selective acknowledgements as documented by Request for Comment (RFC) 2018.

Name: Tcp1323Opts
Type: REG_DWORD
Value: 3 default=0
RFC 1323 time stamps and window scaling options. Legal values are: "0" = disable RFC 1323 options, "1" = window scale enabled only, "2" = time stamps enabled only and "3" = both options enabled.

Name: TcpWindowSize
Type: REG_DWORD
Value: 5ae4c default=0
Specifies the receive window size advertised by the TCP/IP stack.

Name: GlobalMaxTcpWindowSize
Type: REG_DWORD
Value: 5ae4c default=0
Specifies the system maximum receive window size advertised by the TCP/IP stack.