Symbian3/SDK/Source/GUID-768CCC6E-16D2-50E8-8EED-EB2C2AF0E9BE.dita
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     1 <?xml version="1.0" encoding="utf-8"?>
       
     2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
       
     3 <!-- This component and the accompanying materials are made available under the terms of the License 
       
     4 "Eclipse Public License v1.0" which accompanies this distribution, 
       
     5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
       
     6 <!-- Initial Contributors:
       
     7     Nokia Corporation - initial contribution.
       
     8 Contributors: 
       
     9 -->
       
    10 <!DOCTYPE concept
       
    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
       
    12 <concept id="GUID-768CCC6E-16D2-50E8-8EED-EB2C2AF0E9BE" xml:lang="en"><title>Overview</title><prolog><metadata><keywords/></metadata></prolog><conbody>
       
    13 <p>The SIP Client Resolver defines the architecture used to resolve or identify
       
    14 the target client when SIP requests are received from the default port. The
       
    15 Symbian SIP stack is implemented as a Symbian server and uses the default
       
    16 UDP and TCP port 5060 to send and receive SIP messages. Many applications
       
    17 or target clients receive SIP messages that use the default port, and the
       
    18 correct target client must be determined. </p>
       
    19 <p>The SIP Client Resolver determines the target client based on the SIP request
       
    20 and the XML-description provided by every SIP Client Resolver API implementation.
       
    21 It requests the resolved ECOM plug-in to connect to the SIP or another server
       
    22 which uses SIP. </p>
       
    23 <section><title>Architectural relationships</title> <p>The Client Resolver
       
    24 API requires the SIP Codec API and the SIP Codec API. </p> <p>The target clients
       
    25 that receive SIP requests must implement the API Client Resolver API. The
       
    26 following are the two methods in which a target client can receive SIP requests: </p> <ul>
       
    27 <li id="GUID-F3BEAD9E-744E-5154-91EC-E0B66034A8F4"><p> <b>Implement the CSIPResolvedClient
       
    28 interface and provide an XML description with their capabilities</b>  </p> <p>The
       
    29 XML description describes the supported content-types and media formats that
       
    30 use SIP headers and SDP m-lines in the ECOM resource file. Client Resolver
       
    31 framework determines the target client by comparing the incoming SIP request
       
    32 to the XML descriptions provided by the <xref href="GUID-F0E4FA44-A41C-3C6F-993E-39CED042A879.dita"><apiname>CSIPResolvedClient</apiname></xref> implementation. </p> </li>
       
    33 <li id="GUID-07B5DFE5-D376-57F7-8ACB-50BB1EF8351B"><p>Implement the <xref href="GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E.dita"><apiname>CSIPResolvedClient2</apiname></xref> interface
       
    34 and add Request-URIs user-part, plug-ins UID, and the client UID to the SIP
       
    35 Client Resolver mapping table in the Central Repository </p> <p>The table
       
    36 maps the user-part of the incoming SIP request’s Request-URI to the related <xref href="GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E.dita"><apiname>CSIPResolvedClient2</apiname></xref> implementation’s
       
    37 UID. SIP Client Resolver framework gives the SIP request to only the plug-ins
       
    38 for which a mapping entry is found in the Central Repository. </p> </li>
       
    39 </ul> <p>This implies that every target client must provide an ECOM plug-in
       
    40 that is used by the Client Resolver Framework. The Client Resolver Framework
       
    41 uses the information in the SIP request and matches it with the XML description
       
    42 or the mapping table entry provided by the target clients. It then decides
       
    43 which target client plug-in to load. </p> </section>
       
    44 <section><title>Class structure</title> <p>SIP Client Resolver must create
       
    45 a class derived from <xref href="GUID-F0E4FA44-A41C-3C6F-993E-39CED042A879.dita"><apiname>CSIPResolvedClient</apiname></xref> or <xref href="GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E.dita"><apiname>CSIPResolvedClient2</apiname></xref> to
       
    46 receive requests outside the SIP dialogs. If the target client is not running,
       
    47 it must be started to enable it to receive SIP requests. </p> <fig id="GUID-B8A796EA-6850-5695-A516-E92629BE7971">
       
    48 <image href="GUID-E77E2E2A-2F2D-549E-ABD6-175E68A406CB_d0e317911_href.png" placement="inline"/>
       
    49 </fig> <p><b>CSIPResolvedClient</b> </p> <p>The target clients must implement
       
    50 the <xref href="GUID-F0E4FA44-A41C-3C6F-993E-39CED042A879.dita"><apiname>CSIPResolvedClient</apiname></xref> interface to receive SIP requests
       
    51 outside SIP dialogs and enable the client resolution mechanism. </p> <p>SIP
       
    52 uses the data provided in the ECOM resource file or, as requested by the implementation
       
    53 to decide which target client is used. </p> <p><b>CSIPResolvedClient2</b> </p> <p>The
       
    54 target clients must implement the <xref href="GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E.dita"><apiname>CSIPResolvedClient2</apiname></xref> interface
       
    55 to receive SIP requests outside SIP dialogs and enable the client resolution
       
    56 mechanism. </p> <p>The SIP stack uses the plug-ins that implement this interface
       
    57 as follows: </p> <ol id="GUID-E3325143-0AA4-5A60-885C-875F388EF0E3">
       
    58 <li id="GUID-816770B7-3A85-5894-9868-64BEE12FD50C"><p>If the SIP request does
       
    59 not contain the Accept-Contact-header, go to step 2. If it does, the SIP stack
       
    60 calls the <xref href="GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E.dita#GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E/GUID-2C145D8C-DB4C-33C9-9CCE-193433909937"><apiname>CSIPResolvedClient2::MatchAcceptContactsL()</apiname></xref> method
       
    61 on all the plug-ins and applies the following logic: </p> <ul>
       
    62 <li id="GUID-5457D39D-DE84-5A3F-8E8B-7E79C863E118"><p>If none of the clients
       
    63 match, go to step 2. </p> </li>
       
    64 <li id="GUID-BE1A9D22-BD88-519E-AC4A-242FC6D3B098"><p>If one of the clients
       
    65 match, send the SIP request to the matching client. </p> </li>
       
    66 <li id="GUID-3A027E2A-C805-595D-B43C-28B19BC07609"><p>If more than one of
       
    67 the clients match, go to step 2. </p> </li>
       
    68 </ul> </li>
       
    69 <li id="GUID-7F822965-0220-52A8-8CAF-EACA4D87E75D"><p>If the SIP request does
       
    70 not contain the Event-header, go to step 3. If it does, SIP stack calls the <xref href="GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E.dita#GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E/GUID-9DB2CFFE-09ED-367D-9C14-6917F8E3DCF4"><apiname>CSIPResolvedClient2::MatchEventL()</apiname></xref> method
       
    71 on all the plug-ins and applies the following logic: </p> <ul>
       
    72 <li id="GUID-8E85F9F9-D645-53D7-A4D8-6717951B0D1C"><p>If none of the clients
       
    73 match, go to step 3. </p> </li>
       
    74 <li id="GUID-B713BE42-D8AF-51D6-8832-D0B221CFF4D8"><p>If one of the clients
       
    75 match, send the SIP request to the matching client. </p> </li>
       
    76 <li id="GUID-93037264-2B67-5DD4-990B-9D3EEEDE6C4D"><p>If more than one of
       
    77 the clients match, go to step 3. </p> </li>
       
    78 </ul> </li>
       
    79 <li id="GUID-BFCEF7B8-4068-58E6-B960-27035A5A52D6"><p>The SIP stack calls
       
    80 the <xref href="GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E.dita#GUID-30BC7BC4-0FBE-3C60-A2E4-2E5AE206C61E/GUID-9C9E49C8-602B-3C1C-B036-A176FF323A54"><apiname>CSIPResolvedClient2::MatchRequestL()</apiname></xref> method on all
       
    81 the plug-ins and applies the following logic: </p> <ul>
       
    82 <li id="GUID-86228E63-7E10-571E-B465-EB4D14E8855D"><p>If none of the clients
       
    83 match, an error response is generated. </p> </li>
       
    84 <li id="GUID-6F578483-34E7-5CFB-A565-2209FFF82D28"><p>If one of the clients
       
    85 matches, send the SIP request to the matching client. </p> </li>
       
    86 <li id="GUID-C1BD2E18-CFEB-558F-9F10-60EF6B9539E7"><p>If more than one of
       
    87 the clients match, one of the client is randomly selected and the SIP request
       
    88 is sent to it. Normally, the ROM-based clients are preferred. </p> </li>
       
    89 </ul> </li>
       
    90 </ol><p>The channel UIDs must be unique across all SIP clients. The clients
       
    91 may use UIDs assigned for the binaries. </p> </section>
       
    92 </conbody><related-links>
       
    93 <link href="GUID-5C215C64-5D3D-5B65-A11F-BE6F8C306CF4.dita"><linktext>How     
       
    94            the target client is resolved using CSIPResolvedClient</linktext>
       
    95 </link>
       
    96 <link href="GUID-AFE7F3DA-6D61-5A4C-A08F-C998C8805A06.dita"><linktext>How     
       
    97            the target client is resolved using CSIPResolvedClient2</linktext>
       
    98 </link>
       
    99 </related-links></concept>