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<task id="GUID-6822E7FA-D055-5693-8872-8D0E8554A734" xml:lang="en"><title>Configuring

the TCP Receive Window</title><shortdesc>How to configure the TCP receive window. </shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>

<prereq id="GUID-C1DA7D2C-54A2-5547-A0E0-52DE599A96FA"><p>Before you start,

you must understand the following: </p> <ul>

<li id="GUID-AABAB9C2-A530-53C7-ADBC-9596793B7438"><p> <xref href="GUID-8A678AE5-A133-58EA-A4DD-B5BFC94D3AEA.dita#GUID-8A678AE5-A133-58EA-A4DD-B5BFC94D3AEA/GUID-CDAA0409-6ECB-5ABB-A0E5-F7C5C58E6347">Bearer types</xref>  </p> </li>

<li id="GUID-BC616747-9E4B-52C2-94D0-F99402199698"><p> <xref href="GUID-8A678AE5-A133-58EA-A4DD-B5BFC94D3AEA.dita#GUID-8A678AE5-A133-58EA-A4DD-B5BFC94D3AEA/GUID-E1123CF2-EA87-5F18-8F3C-3FD98DD6ABE8"> Lookup table</xref>  </p> </li>

<li id="GUID-74EA5607-4298-5742-99F4-46222968443B"><p> <xref href="http://www.ietf.org/rfc/rfc1323.txt" scope="external">TCP window scaling</xref>  </p> </li>

</ul> </prereq>

<steps id="GUID-82094A75-1D96-534F-A536-2EFD0521AEFD">

<step id="GUID-0DCC20CB-3465-5CE5-9EB3-96B689EF1CE5"><cmd>To configure the

TCP receive window.</cmd>

<info><p>The <xref href="GUID-DCF64049-44EA-3EF9-9A80-D364D56670B2.dita"><apiname>CTCPReceiveWindowSize()</apiname></xref> class defines the

public interface that the Licensee's NetMcpr must use to configure the TCP

receive window. </p></info>

</step>

<step id="GUID-137AC4D5-F8EC-5B99-9D97-F5710FFBAA8E"><cmd>To set the receive

window for different bearers.</cmd>

<info>Licensees need to override the <xref href="GUID-5AC853D0-31FB-3944-8769-A59977F616B0.dita"><apiname>SetTcpWin()</apiname></xref> function

to set the TCP receive window for different bearers. </info>

</step>

<step id="GUID-966B3D6A-0252-5130-8917-A54B27770D62"><cmd>Use the <xref href="GUID-D3A23EB5-4EBF-3F2C-9EE1-2D93A6094109.dita"><apiname>SetTCPwin()</apiname></xref> function

to set the TCP receive window size.</cmd>

<substeps id="GUID-6A7AFF4E-FEB2-5DBA-9514-F8DC9A655CD4">

<substep id="GUID-3938CFE3-7959-5820-B8D2-DF98E6038600"><cmd>To configure

the Max TCP receive window size per TCP socket</cmd>

<info>If licensees want to configure the Max TCP receive window size per TCP

socket, then they must specify a value greater than the Max value configured

in the <codeph>tcpip.ini</codeph> file. </info>

</substep>

<substep id="GUID-E458A87D-EEBC-5B8E-A3B3-3CE46E36A4E8"><cmd>To set the TCP

receive Max value uniform across all sockets</cmd>

<info>If licensees want to set the TCP receive Max value uniform across all

sockets, then they must specify the value in the <codeph>tcpip.ini</codeph> file

and set the iMaxWinSize = 0. So, MaxWinSize is always configured from the <codeph>tcpip.ini</codeph> file. </info>

</substep>

</substeps>

</step>

<step id="GUID-0C4CC4AB-9198-5EE2-B874-CEC90BAF47C3"><cmd>Use the <xref href="GUID-AB233410-30BD-36D8-A50F-CE669141D083.dita"><apiname>AppendExtensionL()</apiname></xref> function

to add the pointer to the lookup table.</cmd>

<info> The lookup table holds the TCP receive window size for different bearer

types. </info>

</step>

</steps>

<example id="GUID-041AB0DF-6C70-57D0-91B2-D37ECD289853"><title>Configuring

the TCP receive window example</title> <p>The following code snippet shows

how to configure the TCP receive window size: </p> <codeblock id="GUID-20989729-9AF1-5E36-8F19-EDE0D83D42E8" xml:space="preserve">

// Licensees need to override the SetTCPwin() function

CNokiaTCPRecvWindow: Public CTCPReceiveWindowSize

{

  public:

   virtual void SetTCPwin(TUint aBearerType)

    {

       //Set iWinSize  based on the bearer type

    // If Licensees want to configure the Max TCP receive window size per TCP socket, 

    // then they must specify a value greater than the max value configured in the tcpip.ini file.

    // If Licensees want to set the TCP Receive max value uniform across all sockets, 

    // then they must specify the value in the tcpip.ini file and set the iMaxWinSize =0.

    // So MaxWinSize will always be configured from the tcpip.ini file.

    }    

};

CNetworkMetaConnectionProvider::ConstructL()

{

CTCPReceiveWindowSize * iRecvWIndow = New(ELeave) CNokiaTCpRecvWindow();

//Append the pointer to the lookup table. The Pointer is of the type CTCPReceiveWindowSize.

iAccessPointConfig->AppendExtensionL(iReceiveWindow);

}

</codeblock> </example>

</taskbody><related-links>

<link href="GUID-8A678AE5-A133-58EA-A4DD-B5BFC94D3AEA.dita"><linktext>Variable

TCP Receive                 Window</linktext></link>