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TIP: Tcp performance Options

By jobeard
Mar 9, 2008
  1. The following TCP options will generally improve your Windows XP network performance.
    Windows 2000 users have more straight forward setting

    SackOpts
    All of the TCP/IP parameters are registry values located under the registry key
    Code:
    HKEY_LOCAL_MACHINE
         \SYSTEM
              \CurrentControlSet
                   \Services:
                        \Tcpip
                             \Parameters
                                 \Interfaces
                                    {[b]GUID-1[/b]}
                                    {[b]GUID-2[/b]}
                                     ....
                                    {[b]GUID-n[/b]}
    Adapter-specific values are listed under subkeys for each adapter identified by the adapter's globally unique identifier (GUID).

    To determine the GUID value for an adapter corresponding to a LAN connection in the Network Connections folder, do the following:

    1.Open the Network Connections folder and note the name of the LAN connection, such as "Local Area Connection."

    2.Click Start, click Run, type regedit.exe, and then click OK.

    3.Use the tree view (the left pane) of the Registry Editor tool to open the following key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Network\{4D36E972-E325-11CE-BFC1-08002BE10318}

    4.Under this key are one or more keys for the globally unique identifiers (GUIDs) corresponding to the installed LAN connections. Each of these GUID keys has a Connection subkey. Open each of the GUID\Connection keys and look for the Name setting in the contents pane whose value matches the name of your LAN connection from step 1.

    5.When you have found the GUID\Connection key that contains the Name setting that matches the name of your LAN connection, write down or otherwise note the GUID value.

    6. Navigate to:
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Tcpip\Parameters\Interfaces\{GUID}
    and add new key SackOpts REG_DWORD value 1
    Full Duplex

    Under the Device Manager, dbl-click your Network Adapter name
    click the Advanced Tab
    select the Link Speed/Duplex Mode
    change the Value: box to 100mbps/Full Duplex
    click OK to save the value

    for those with only a 10mps card, that choice will be present too
     
  2. tipstir

    tipstir TS Ambassador Posts: 2,387   +105

    TCP-Reg

    Here this might make it easier for members to apply these settings.. Just download the files attached. TCP.zip is for DSL modems and TCP_Cable.zip is for Cable Modems 20Mbps or geater. Settings can be adjusted with TCP Optimizer from www.speedguide.net.

    CABLE Modems 20Mbps or higher

    REGEDIT5

    [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
    "SackOpts"=dword:00000001
    "Tcp1323Opts"=dword:00000001
    "TcpMaxDataRetransmissions"=dword:00000005
    "TcpMaxDupAcks"=dword:00000002
    "TcpNumConnections"=dword:00000064
    "GlobalMaxTcpWindowSize"=dword:000faf00
    "TcpWindowSize"=dword:000faf00
    "DefaultTTL"=dword:00000040
    "DisableUserTOSSetting"=dword:00000000
    "DefaultTOSValue"=dword:00000050
    "EnablePMTUDiscovery"=dword:00000001
    "DisableTaskOffload"=dword:00000000

    DSL Modems

    REGEDIT4

    [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
    "Tcp1323Opts"=dword:00000001
    "GlobalMaxTcpWindowSize"=dword:000a00b0
    "TcpWindowSize"=dword:000a00b0
    "EnablePMTUDiscovery"=dword:00000001
    "SackOpts"=dword:00000001
    "TcpMaxDupAcks"=dword:00000002
    "DisableTaskOffload"=dword:00000000
    "EnablePMTUBHDetect"=dword:00000000
    "DefaultTTL"=dword:00000040

    The above is what I use and I've attached a zip with a TCP.reg so you just double click on the file and it will install what you need for DSL and Cable Modem users. P2P is different for Cable Modem as it would have the Max settings.
     
  3. LookinAround

    LookinAround Ex Tech Spotter Posts: 6,491   +183

    I'll second tipster's tool recommendation. I've used these TCP Analysis/Optimizer tools before. Optimizer tool is also handy as it provides you an easy way to back up/restore your TCP registry settings as you use it to tweak/try out/see what happens changing some parameters.
     
  4. jobeard

    jobeard TS Ambassador Topic Starter Posts: 9,311   +617

    good info guys. The MS site documents the key

    [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
    as that used by Win/2000 while XP has it parameters relative to the adapter itself

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Tcpip\Parameters\Interfaces\{GUID}

    the location for GLOBAL Tcp parms is here:
    Key: Tcpip\Parameters
    TcpMaxDupAcks

    while the Interface specific parms are here:
    Key: Tcpip\Parameters, Tcpip\Parameters\Interface\interfaceGUID
    TcpWindowSize

    For those that use BOTH WiFi when travellng and NIC connections at home,
    be sure to set your tweaks at the PER Interface level.
     
  5. tipstir

    tipstir TS Ambassador Posts: 2,387   +105

    Wireless uses a different TCP and it's NIC has to be setup right.. One thing not mention here is the:

    Link-Layer Topology Discovery Responder - Protocol that should be installed on both wired and wireless NIC server, workstation, desktop and laptop. This allows PCs to be discovered on a the network. For XP and Vista.

    WindowsXP-KB922120-v5-x86-ENU.exe
     
  6. jobeard

    jobeard TS Ambassador Topic Starter Posts: 9,311   +617

    hum; Following the MS Instructions to identify the adapters will show the wireless as well
    as the NIC GUIDs and the Connection Names (eg Local Lan vs. Wireless Connection)
    Navigating to the TCP section, both GUIDs are present (according to my laptop) and the
    TCP\Parameters are all there too.

    Link Layer Topology Discovery (LLTD) is a new component that can be downloaded for XP
    (but resident in Vista), and is unnecessary for any connection to any ISP, P2p, or Server.
    It will allow an XP system to be discovered and displayed in the Vista View Network Map.
    (see KB article)
     
  7. tipstir

    tipstir TS Ambassador Posts: 2,387   +105

    I am using to fix network discovery problems between systems and it fixed all except for one. I don't want to use SP3 for XP..
     
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