Optimize Broadband Cable Modem and DSL Connections (Windows 2000/XP) Popular

These settings allow you to boost the speed of your broadband Internet connection when using a Cable Modem or DSL Router with Windows 2000 and Windows XP.
	This tweak can be easily applied using WinGuides Tweak Manager.
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Open your registry and find the key below.

Create the following DWORD values, as most of these values will not already exist you will need to create them by clicking on 'Edit -> New -> DWORD Value' and then set the value as shown below.

DefaultTTL = "80" hex (or 128 decimal)
Specifies the default time to live (TTL) for TCP/IP packets. The default is 32.

EnablePMTUBHDetect = "0"
Specifies whether the stack will attempt to detect Maximum Transmission Unit (MTU) routers that do not send back ICMP fragmentation-needed messages. The default is 0.

EnablePMTUDiscovery = "1"
Specifies whether the TCP/IP stack will attempt to perform path MTU discovery as specified in RFC 1191. The default is 1.

GlobalMaxTcpWindowSize = "7FFF" hex (or 32767 decimal)
Specifies the system maximum receive window size advertised by the TCP/IP stack.

TcpMaxDupAcks = "2"
Determines the number of duplicate ACKs that must be received for the same sequence number of sent data before "fast retransmit" is triggered.

SackOpts = "1"
Enables support for selective acknowledgements as documented by Request for Comment (RFC) 2018. Default is 0.

Tcp1323Opts = "1"
Controls RFC 1323 time stamps and window scaling options. Possible values are: "0" = disable RFC 1323 options, "1" = window scale enabled only, "2" = time stamps enabled only and "3" = both options enabled.

TcpWindowSize = "7FFF" hex (or 32767 decimal)
Specifies the receive window size advertised by the TCP/IP stack. If you have a latent network you can try increasing the value to 93440, 186880, or 372300.

Exit your registry and restart Windows for the changes to take effect.

Note: These optimized settings may not work with all ISP configurations, in which case the parameters should be returned to the default values.
Registry Editor Example
|	Name	Type	Data	|
|		(Default)	REG_SZ	(value not set)	|
|		DefaultTTL	REG_DWORD	0x00000080 (128)	|
|		EnablePMTUBHDetect	REG_DWORD	0x00000000 (0)	|
|		EnablePMTUDiscovery	REG_DWORD	0x00000001 (1)	|
|		GlobalMaxTcpWindowSize	REG_DWORD	0x00007fff (32767)	|
|		TcpMaxDupAcks	REG_DWORD	0x00000002 (2)	|
|		SackOpts	REG_DWORD	0x00000001 (1)	|
|		Tcp1323Opts	REG_DWORD	0x00000001 (1)	|
|		TcpWindowSize	REG_DWORD	0x00007fff (32767)	|
-
|	HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\P...	|
-
Registry Settings
System Key: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
Data Type: REG_DWORD (DWORD Value)



Note: I run my cable connection GlobalMaxTcpWindowSize at 500000. I have notice that my speed browsing the web is quite fast. A real good setting for those tweaks is TcpWindowSize 0x0003ebc0 (256960) and GlobalMaxTcpWindowSize 	0x00007a120 (500000).