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<concept id="GUID-AFE7F3DA-6D61-5A4C-A08F-C998C8805A06" xml:lang="en"><title>How

the target Client is Resolved using CSIPResolvedClient2</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>The SIP Client Resolver determines the target clients by comparing the

Request-URI of the incoming SIP request to the information stored in SIP Client

Resolver mapping table in the Central Repository. The information required

to access the map table in the Central Repository is defined in the <filepath>sipclientresolverconfigcrkey.h</filepath> file.

The incoming SIP request compares with the Request-URI’s user part in the

Central Repository mapping table. </p>

<p>If a match is found, the related ECOM plug-in is loaded by its UID. The

loaded plug-in matches the incoming SIP requests based on their fields. If

the request matches, the plug-in returns the UID of the matching client. SIP

Client Resolver requests the resolved ECom plug-in to connect to the Symbian

platform server that uses SIP. </p>

<p>The resource (<filepath>.rss</filepath>) file contains the information

in the Central Repository and also the following information: </p>

<ul>

<li id="GUID-6CF8E2D5-5BF3-5E56-93BE-97A0D2054B0E"><p> <codeph> dll_uid</codeph> and <codeph>implementation_uid</codeph>:

These UIDs are obtained from <xref href="http://www.symbiansigned.com" scope="external">Symbian

Signed</xref>. </p> <p> <b>Note:</b> Both these UIDs can be the same. </p> </li>

<li id="GUID-A2F95B01-F707-51D1-AD67-4EB364865C33"><p>The <codeph>interface_uid</codeph> must

be <codeph>0x10282EE5</codeph>. </p> </li>

</ul>

<section id="GUID-D0D9C1C9-C0A1-4C4C-ACA6-14C23D651E38"><title>Resolving the target client using CSIPResolvedClient2</title> <p>The

following illustration shows how the SIP Client Resolver subsystem resolves

the target client implementing <xref href="GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E.dita"><apiname>CSIPResolvedClient2</apiname></xref> and

requests the resolved client to connect to the SIP implementation. </p> <fig id="GUID-750221F0-A98E-5C47-B804-5A6CDD16B2E9">

<title>              Call flow of resolving a target client implementation

using              CSIPResolvedClient2            </title>

<image href="GUID-8EF8CDD3-9FFE-5C39-8303-67A661C67F6B_d0e552887_href.jpg" placement="inline"/>

</fig> <p>The target clients must implement the <xref href="GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E.dita"><apiname>CSIPResolvedClient2</apiname></xref> interface

to receive SIP requests including SIP dialogs and enable the client resolution

mechanism. <b/><b>Note</b>: The channel UIDs must be unique across all

SIP clients. For example clients may use UIDs assigned for binaries. </p> <p>The

SIP stack uses the plug-ins that implement the <xref href="GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E.dita"><apiname>CSIPResolvedClient2</apiname></xref> interface

as follows: </p> <ol id="GUID-E0C735BE-BBBD-533B-AB2B-59F8936060BA">

<li id="GUID-7854B67A-2143-5EA4-949D-B3C96CA51866"><p>If the SIP request does

not contain an Accept-Contact-header, go to step 2. If it does, the SIP stack

calls <codeph>CSIPResolvedClient2::MatchAcceptContactsL</codeph> for all the

plug-ins and applies the following logic: </p> <ul>

<li id="GUID-E975B348-52DB-519A-9AC0-98821BA27E95"><p>If none of the clients

match, go to step 2 </p> </li>

<li id="GUID-99DB2FEE-470B-5E76-8183-AD2C0E1B6FF0"><p>If one of the client

match, the SIP request is sent to the matching client </p> </li>

<li id="GUID-5F420FD9-2AEE-5517-A216-FA3868941902"><p>If more than one of

the clients match, go to step 2 </p> </li>

</ul> </li>

<li id="GUID-F28D6940-D404-5E0F-B52A-6A47980ADA68"><p>If the SIP request does

not contain an Event-header go to step 3. If it does, the SIP stack calls <codeph>CSIPResolvedClient2::MatchEventL</codeph> for

all the plug-ins and applies the following logic: </p> <ul>

<li id="GUID-390E2FBC-305E-59C0-BE1F-E7C961B47251"><p>If none of the clients

match, go to step 3 </p> </li>

<li id="GUID-6A41D1A5-7636-51CC-864D-F2AB095D97E6"><p>If one of the client

match, the SIP request is sent to the matching client </p> </li>

<li id="GUID-8C51B40C-FC7B-566E-B56F-4279233C192E"><p>If more than one of

the clients match, go to step 3 </p> </li>

</ul> </li>

<li id="GUID-9C094348-B7F4-572D-B49B-B99F81C902F2"><p>The SIP stack calls <codeph>CSIPResolvedClient2::MatchRequestL</codeph> for

all the plug-ins and applies the following logic: </p> <ul>

<li id="GUID-63351732-E32A-58BC-8F32-7BA3832788FD"><p>If none of the clients

match, the SIP generates an error response </p> </li>

<li id="GUID-9E8765F8-A55F-5EA3-A63E-ACBF8A4BEF24"><p>If one of the client

match, the SIP request is sent to the matching client </p> </li>

<li id="GUID-AE679FD1-163D-5F3B-ADE8-1C6AEF490552"><p>If more than one of

the clients match, SIP selects one of these clients randomly and sends the

request to it. The ROM-based clients are preferred. </p> </li>

</ul> </li>

</ol> </section>

<section id="GUID-026A9B43-E096-4D32-AC3B-2DDC7974FFF6"><title>See also</title> <p> <xref href="GUID-0D579DDC-0A8A-5CFA-8194-CAA955B65A57.dita">Example

of a SIP Client Resolver Plug-in</xref>  </p> </section>