--- a/Symbian3/SDK/Source/GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita Wed Mar 31 11:11:55 2010 +0100
+++ b/Symbian3/SDK/Source/GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita Fri Jun 11 12:39:03 2010 +0100
@@ -1,185 +1,185 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
-<!-- This component and the accompanying materials are made available under the terms of the License
-"Eclipse Public License v1.0" which accompanies this distribution,
-and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
-<!-- Initial Contributors:
- Nokia Corporation - initial contribution.
-Contributors:
--->
-<!DOCTYPE concept
- PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
-<concept id="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F" xml:lang="en"><title>Overview</title><prolog><metadata><keywords/></metadata></prolog><conbody>
-<p>The SIP Client API manages the multimedia sessions, subscribes to events,
-and sends SIP messages. It also provides access to the basic services of the
-SIP stack such as: </p>
-<ul>
-<li id="GUID-E9BF6031-1DAF-5238-A306-C44F0F91682D"><p>Sending and receiving
-of SIP messages </p> </li>
-<li id="GUID-C6A3FA97-1F09-587E-9504-9685D8306B04"><p>Creating registrations </p> </li>
-<li id="GUID-A02F02C7-A903-53E0-A64E-F0B62C93A90F"><p>Forming and tearing
-down dialogs initiated by INVITE, REFER and SUBSCRIBE requests </p> </li>
-</ul>
-<section id="GUID-8D3D5FB3-6037-5956-B3F0-DB14BD1BB17B"><title>Architectural
-relationships</title> <p>The SIP Client API uses the client-server mechanism
-to interact with the SIP stack. This means more than one client can use the
-SIP stack at the same time. The calls to the SIP Client API are synchronous.
-The SIP Client API implements a set of callback functions to pass the events
-back to the application. </p> <p><b>Capability information</b> </p> <p>The
-following table describes the capabilities required to use the SIP Client
-API and the conditions in which they are required: </p> <table id="GUID-B3DCF31A-C6D5-58B9-87FA-B2CD3E0ABA1F">
-<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>
-<thead>
-<row>
-<entry>Capability </entry>
-<entry>Reason needed </entry>
-</row>
-</thead>
-<tbody>
-<row>
-<entry><p>NetworkServices </p> </entry>
-<entry><p>to send or receive SIP messages </p> </entry>
-</row>
-<row>
-<entry><p>WriteDeviceData </p> </entry>
-<entry><p>to create an instance of the <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> class </p> </entry>
-</row>
-<row>
-<entry><p>NetworkControl </p> <p>Location </p> <p>ReadDeviceData </p> </entry>
-<entry><p>to use the function <codeph>CSIPConnection::SetOptL()</codeph> </p> </entry>
-</row>
-</tbody>
-</tgroup>
-</table> <p><b>Extending the API</b> </p> <p>SIP Client API cannot be extended. </p> </section>
-<section id="GUID-E055BF09-9605-57E6-9502-CB3F4CAC29B8"><title>SIP Client
-API class structure</title> <ul>
-<li id="GUID-3E500E7D-ECB9-50F8-B996-A212EE294E68"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-581B8017-EAA0-59CB-A9CB-490370E0CEC9"> CSIP, MSIPObserver, CSIPConnection and MSIPConnectionObserver</xref> </p> </li>
-<li id="GUID-461F8201-ED85-582A-945C-7471F9BF27AA"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-0E726099-31C4-5DD4-9AEA-67765589F462">Registration services</xref> </p> </li>
-<li id="GUID-F69AEAB7-0E13-5673-B696-843957CC4C72"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-80CE8929-9DFD-5DCA-A929-662BD996223B"> SIP dialog associations</xref> </p> </li>
-<li id="GUID-BFE257A7-EF1A-58BF-A047-00E0B11B1FD3"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-B0D208E4-D1F9-5C5F-B937-11118E778074">Requests sent to, and received from, the network</xref> </p> </li>
-<li id="GUID-D0AC4583-B181-501C-A97A-63F094AD4046"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-0427709F-CD4B-5363-9377-10402B8A5819">SIP message related classes</xref> </p> </li>
-<li id="GUID-31ED307B-2285-5DE0-A83B-D0CB7A8C585D"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-4E4FAFCA-0BF6-510C-B8E3-28A83936A154">Automatically refreshing a SIP request</xref> </p> </li>
-<li id="GUID-B6E46736-A250-5064-B4F8-595A20025478"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-B71BC486-18C2-5E71-965E-0881FBA9CE85">Managing HTTP digest security settings</xref> </p> </li>
-</ul> <p id="GUID-581B8017-EAA0-59CB-A9CB-490370E0CEC9"><b> CSIP, MSIPObserver,
-CSIPConnection and MSIPConnectionObserver </b> </p> <fig id="GUID-0834012C-083F-5FA0-B29D-E3E852165528">
-<image href="GUID-4381EA7F-BE75-5B43-BE97-C97D71D04377_d0e338573_href.png" placement="inline"/>
-</fig> <p>An application creates a single instance of the <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> class,
-and implements the callback functions defined by <xref href="GUID-C6FF4A83-0097-3A82-B4ED-802E1FEA05D1.dita"><apiname>MSIPObserver</apiname></xref>.
-The <codeph>CSIP</codeph> uses the <codeph>MSIPObserver</codeph> functions.
-The <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> class asks the supported security mechanisms and
-determines whether a <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> object exists for a
-given IAP. </p> <p>The <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> object creates an instance
-of <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> that allows you to send standalone SIP
-requests and ask for the state of the network connection. Responses are received
-through the <xref href="GUID-B889A3FD-3B14-3785-90AE-3546F0C9A5D4.dita"><apiname>MSIPConnectionObserver</apiname></xref> interface that defines
-a set of callback functions that an application must implement. </p> <p>An
-application can have many <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> objects, but each
-of them must have a different IAP. </p> <p id="GUID-0E726099-31C4-5DD4-9AEA-67765589F462"><b>Registration
-services</b> </p> <fig id="GUID-63E38B2E-975E-554C-8EDC-65B8BBA86838">
-<image href="GUID-E4543D60-A9D0-5121-9540-993BB15D3275_d0e338630_href.png" placement="inline"/>
-</fig> <p>An existing <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> is required to create
-an instance of <codeph>CSIPRegistrationBinding</codeph>. The <xref href="GUID-48AA01D5-CE7B-3C22-B2E0-529261121EC4.dita"><apiname>CSIPRegistrationBinding</apiname></xref> class
-provides services for registration, updating the registration, and deregistration.
-This class also provides instructions to the SIP stack to automatically refresh
-the registration, and to query and set the outbound proxy used by the registration. </p> <p id="GUID-80CE8929-9DFD-5DCA-A929-662BD996223B"><b> SIP dialog
-associations</b> </p> <fig id="GUID-4870BE80-44B6-50F0-B77E-73FEAD136304">
-<image href="GUID-17D1489B-F7F7-5CA7-9F81-850AA9ACEFEB_d0e338655_href.png" placement="inline"/>
-</fig> <p> <xref href="GUID-9841AF1A-B8CF-3BA1-8445-93064549AE8C.dita"><apiname>CSIPDialogAssocBase</apiname></xref> is the base class for SIP
-dialog associations, such as <xref href="GUID-B4A2FBBD-2B5F-3E64-800D-C4E9203679A8.dita"><apiname>CSIPInviteDialogAssoc</apiname></xref>, <xref href="GUID-9539CAEE-28AE-3134-8415-EEBCBCDA4D18.dita"><apiname>CSIPSubscribeDialogAssoc</apiname></xref>, <xref href="GUID-2E7EF887-ED59-3E8A-B9A2-686DF879A16C.dita"><apiname>CSIPReferDialogAssoc</apiname></xref> and <xref href="GUID-72F96612-A95C-3066-BFF0-2E288C945A2A.dita"><apiname>CSIPNotifyDialogAssoc</apiname></xref>. The <xref href="GUID-9841AF1A-B8CF-3BA1-8445-93064549AE8C.dita"><apiname>CSIPDialogAssocBase</apiname></xref> class
-is used to obtain the associated SIP dialog, for the associated <xref href="GUID-382BC1BE-3CF3-3E81-B1FF-341EEF2B67EA.dita"><apiname>CSIPDialog</apiname></xref> instance,
-and for sending a non-target Refresh request within the dialog. </p> <p> <b> Note: </b> The
-SIP Client API creates the <xref href="GUID-382BC1BE-3CF3-3E81-B1FF-341EEF2B67EA.dita"><apiname>CSIPDialog</apiname></xref> instance, it cannot
-be created by the application. </p> <p>If any of the <xref href="GUID-B4A2FBBD-2B5F-3E64-800D-C4E9203679A8.dita"><apiname>CSIPInviteDialogAssoc</apiname></xref>, <xref href="GUID-9539CAEE-28AE-3134-8415-EEBCBCDA4D18.dita"><apiname>CSIPSubscribeDialogAssoc</apiname></xref>, <xref href="GUID-2E7EF887-ED59-3E8A-B9A2-686DF879A16C.dita"><apiname>CSIPReferDialogAssoc</apiname></xref> and <xref href="GUID-72F96612-A95C-3066-BFF0-2E288C945A2A.dita"><apiname>CSIPNotifyDialogAssoc</apiname></xref> objects
-are associated, they are bound to an existing <xref href="GUID-382BC1BE-3CF3-3E81-B1FF-341EEF2B67EA.dita"><apiname>CSIPDialog</apiname></xref> object,
-or they can be used to create a new <codeph>CSIPDialog</codeph> object. </p> <p> <b>Note:</b> </p> <ul>
-<li id="GUID-6A085F6F-C243-53AD-B33C-F37D14DFE0A4"><p> <xref href="GUID-B4A2FBBD-2B5F-3E64-800D-C4E9203679A8.dita"><apiname>CSIPInviteDialogAssoc</apiname></xref> allows
-an application to initiate a dialog and to send <codeph>INVITE</codeph>,,<codeph>PRACK</codeph>,,<codeph>ACK</codeph>, <codeph>UPDATE,</codeph> and <codeph>BYE</codeph> requests related to the dialog. </p> </li>
-<li id="GUID-19C504F0-EAD5-524A-82E9-2D15BFA2A6D2"><p> <xref href="GUID-9539CAEE-28AE-3134-8415-EEBCBCDA4D18.dita"><apiname>CSIPSubscribeDialogAssoc</apiname></xref> allows
-an application to subscribe to different events by sending SUBSCRIBE and UNSUBSCRIBE
-requests. It also orders the SIP stack to automatically refresh the SUBSCRIBE
-request. </p> </li>
-<li id="GUID-C47B74D8-2251-5FCC-A356-1364EB61CF05"><p> <xref href="GUID-2E7EF887-ED59-3E8A-B9A2-686DF879A16C.dita"><apiname>CSIPReferDialogAssoc</apiname></xref> allows
-an application to define and send REFER requests. </p> </li>
-<li id="GUID-18AD2000-2A37-5CD9-8118-8B3322211D28"><p> <xref href="GUID-72F96612-A95C-3066-BFF0-2E288C945A2A.dita"><apiname> CSIPNotifyDialogAssoc</apiname></xref> allows
-an application to define and send NOTIFY requests. </p> </li>
-</ul> <p id="GUID-B0D208E4-D1F9-5C5F-B937-11118E778074"><b>Sent and received
-network requests</b> </p> <fig id="GUID-2E0C9020-1863-5644-BF7E-62B4DB9104D2">
-<image href="GUID-F5A82F61-B93A-5652-93A4-B9CE877B4D4A_d0e338792_href.png" placement="inline"/>
-</fig> <p>When a SIP request is sent to the network, the SIP Client API implementation
-creates a <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> object and returns it to
-the application. A <codeph>CSIPClientTransaction</codeph> object represents
-the SIP transaction and consists of the SIP request and the SIP response.
-After receiving a response, the application gets <xref href="GUID-13F32052-70BE-3B4D-9F8B-DF2DABB896B0.dita"><apiname>CSIPResponseElements</apiname></xref> from
-the <codeph>CSIPClientTransaction</codeph> object. <b>Note:</b> Some client
-transactions can also be cancelled or refreshed. </p> <p>When a SIP request
-is received from the network, it is passed to the application as a <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> object.
-The application gets <xref href="GUID-19FB031A-CFA7-3C67-A627-CFF501060AA5.dita"><apiname>CSIPRequestElements</apiname></xref> from the <codeph>CSIPServerTransaction</codeph> object.
-A <codeph>CSIPRequestElements</codeph> object describes the kind of SIP request
-received. After the application determines the type of response to send, it
-uses the <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> to send the responses. </p> <p> <xref href="GUID-93256B64-49C9-37F1-9A4E-72C521759749.dita"><apiname>CSIPTransactionBase</apiname></xref> is
-the base class for <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> and <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref>.
-It provides the functions to obtain the current state of the transaction and
-the transaction type. Some operations are only allowed when the transaction
-is in a certain state. <b>Note:</b> The SIP Client API creates instances of <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> and <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> and they cannot be created by the application. </p> <p id="GUID-0427709F-CD4B-5363-9377-10402B8A5819"><b>SIP
-message related classes</b> </p> <fig id="GUID-B99CF040-E91F-5281-8AAC-2151049C0EA8">
-<image href="GUID-6290D35A-7A41-5B9E-882A-E14F6D165ED7_d0e338869_href.png" placement="inline"/>
-</fig> <p>When a SIP request is sent to the network, the SIP Client API implementation
-creates a <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> object and returns it to
-the application. A <codeph>CSIPClientTransaction</codeph> object represents
-the SIP transaction and consists of the SIP request and the SIP response.
-After receiving a response the application gets <xref href="GUID-13F32052-70BE-3B4D-9F8B-DF2DABB896B0.dita"><apiname>CSIPResponseElements</apiname></xref> from
-the <codeph>CSIPClientTransaction</codeph> object. <b>Note:</b> Some client
-transactions can be cancelled or refreshed. </p> <p>When a SIP request is
-received from the network, it is passed to the application as a <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> object.
-The application gets <xref href="GUID-19FB031A-CFA7-3C67-A627-CFF501060AA5.dita"><apiname>CSIPRequestElements</apiname></xref> from the <codeph>CSIPServerTransaction</codeph> object.
-A <codeph>CSIPRequestElements</codeph> object describes the type of SIP request
-received. After the application determines the type of response to send, it
-uses the <codeph>CSIPServerTransaction</codeph> to send the responses. </p> <p> <xref href="GUID-93256B64-49C9-37F1-9A4E-72C521759749.dita"><apiname>CSIPTransactionBase</apiname></xref> is
-the base class for <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> and <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref>.
-It provides functions to obtain the current state of the transaction and the
-transaction type. Some operations are only allowed when the transaction is
-in a certain state. <b>Note:</b> The SIP Client API creates instances of <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> and <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> and they cannot be created by the application. </p> <p id="GUID-4E4FAFCA-0BF6-510C-B8E3-28A83936A154"><b> Automatically
-refreshing a SIP request</b> </p> <fig id="GUID-49ACB697-512C-5FCF-AD48-20D6AAB0FEFC">
-<image href="GUID-6B9E5B8D-E2F7-5972-ABFB-49F7F466EBBD_d0e338945_href.png" placement="inline"/>
-</fig> <p>The SIP stack automatically refreshes a SIP request using the <xref href="GUID-3C166C85-6E17-323B-9CD3-B3E2836DC1C3.dita"><apiname>CSIPRefresh</apiname></xref> object. <codeph>REGISTER</codeph>, <codeph>SUBSCRIBE</codeph> and a request outside the dialog are refreshed. After
-sending a refresh request, the application queries the state of the refresh
-from <codeph>CSIPRefresh</codeph>. </p> <p> <codeph>CSIPRefresh</codeph> provides
-functions for updating and terminating the refresh, for requests outside the
-dialog. The <xref href="GUID-48AA01D5-CE7B-3C22-B2E0-529261121EC4.dita"><apiname>CSIPRegistrationBinding</apiname></xref> and <xref href="GUID-9539CAEE-28AE-3134-8415-EEBCBCDA4D18.dita"><apiname>CSIPSubscribeDialogAssoc</apiname></xref> classes
-are used to update and terminate a refreshed <codeph>REGISTER</codeph> or <codeph>SUBSCRIBE</codeph>. </p> <p id="GUID-B71BC486-18C2-5E71-965E-0881FBA9CE85"><b> Managing HTTP digest security
-settings </b> </p> <fig id="GUID-7C296C1B-67E3-569F-A5E9-92A4F7922088">
-<image href="GUID-1704898B-7836-53C2-8743-F733836EDE7B_d0e338991_href.png" placement="inline"/>
-</fig> <p>An application must create an instance of the <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> class
-to use <codeph>CSIPHttpDigest</codeph>. The <xref href="GUID-F9FBAFBE-A895-3FD3-A526-604A6C9E035D.dita"><apiname>CSIPHttpDigest</apiname></xref> class
-manages HTTP digest security settings and contains only static functions. </p> </section>
-<section id="GUID-4195FAF9-D0D7-5046-BD62-9A314791BEFE"><title>Memory used</title> <p>After
-the <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> and <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> objects
-are created, most of the memory consumed is by <xref href="GUID-77CFD812-7238-3B84-80FF-475BD73C3506.dita"><apiname>CSIPMessageElements</apiname></xref>, <xref href="GUID-19FB031A-CFA7-3C67-A627-CFF501060AA5.dita"><apiname>CSIPRequestElements</apiname></xref> and <xref href="GUID-13F32052-70BE-3B4D-9F8B-DF2DABB896B0.dita"><apiname>CSIPResponseElements</apiname></xref> classes. <xref href="GUID-93256B64-49C9-37F1-9A4E-72C521759749.dita"><apiname>CSIPTransactionBase</apiname></xref> holds the most recent SIP
-response in a <xref href="GUID-13F32052-70BE-3B4D-9F8B-DF2DABB896B0.dita"><apiname>CSIPResponseElements</apiname></xref> object. When another
-response is received, the previous <xref href="GUID-13F32052-70BE-3B4D-9F8B-DF2DABB896B0.dita"><apiname>CSIPResponseElements</apiname></xref> object
-is deleted and a new one is created. </p> <p> <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> contains
-a <xref href="GUID-19FB031A-CFA7-3C67-A627-CFF501060AA5.dita"><apiname>CSIPRequestElements</apiname></xref> object until the SIP request is transferred
-to the server side of the SIP stack. <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> contains
-the SIP request as <xref href="GUID-19FB031A-CFA7-3C67-A627-CFF501060AA5.dita"><apiname>CSIPRequestElements</apiname></xref>. The application
-owns the <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> and <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> objects.
-When the transaction terminates, the application deletes these objects to
-conserve memory. </p> <p>A non-<codeph>INVITE</codeph> <codeph>CSIPClientTransaction</codeph> is
-deleted when it has received a final response or when the <codeph>ErrorOccured()</codeph> callback
-is called. A non-<codeph>INVITE</codeph> <codeph>CSIPServerTransaction</codeph> is
-deleted after the application sends a final response. </p> <p>The <codeph>INVITE</codeph> related
-transactions are deleted if the <codeph>ErrorOccured()</codeph> callback function
-is called. These transactions behave differently because of the presence of
-an <codeph>ACK</codeph>. </p> <p>When the application sends a 2xx response
-to an <codeph>INVITE</codeph> related <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref>,
-it enters the <xref href="GUID-93256B64-49C9-37F1-9A4E-72C521759749.dita#GUID-93256B64-49C9-37F1-9A4E-72C521759749/GUID-DF7E4DCE-1F6D-3F2A-A638-5516A733AA9D"><apiname>CSIPTransactionBase::ETerminated</apiname></xref> state and
-it is deleted at this point. A new <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> object
-receives the ACK. </p> <p>When the application sends an <codeph>INVITE</codeph> request
-and the <codeph>CSIPClientTransaction</codeph> receives a 2xx response, the
-transaction enters the <codeph>CSIPTransactionBase::ETerminated</codeph> state.
-The associated <codeph>CSIPClientTransaction</codeph> must not be deleted
-as it is required to send the <codeph>ACK</codeph> and also to receive the <xref href="GUID-B889A3FD-3B14-3785-90AE-3546F0C9A5D4.dita#GUID-B889A3FD-3B14-3785-90AE-3546F0C9A5D4/GUID-2E76BDA0-CE87-3538-A791-963A90230FD4"><apiname>MSIPConnectionObserver::InviteCompleted()</apiname></xref> callback.
-An <codeph>INVITE</codeph> related <codeph>CSIPClientTransaction</codeph> must
-be deleted only after a <codeph>MSIPConnectionObserver::InviteCompleted</codeph> or <xref href="GUID-D14D6845-1C5E-3C15-8310-574A2A8C6C95.dita#GUID-D14D6845-1C5E-3C15-8310-574A2A8C6C95/GUID-DED382FB-A6D5-37D7-B8E4-05262F690068"><apiname>MSIPConnectionObserver
-::ErrorOccured</apiname></xref> event is received, or if the state of the associated <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> goes
-to <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita#GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94/GUID-68DD22DC-67E4-387B-BBE9-B9B96D9C9016"><apiname>CSIPConnection::EInactive</apiname></xref> or <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita#GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94/GUID-5963A947-BD5C-3B34-9D10-2CB5DC413774"><apiname>CSIPConnection::EUnavailable</apiname></xref>. </p> </section>
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License
+"Eclipse Public License v1.0" which accompanies this distribution,
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+ Nokia Corporation - initial contribution.
+Contributors:
+-->
+<!DOCTYPE concept
+ PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F" xml:lang="en"><title>Overview</title><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>The SIP Client API manages the multimedia sessions, subscribes to events,
+and sends SIP messages. It also provides access to the basic services of the
+SIP stack such as: </p>
+<ul>
+<li id="GUID-E9BF6031-1DAF-5238-A306-C44F0F91682D"><p>Sending and receiving
+of SIP messages </p> </li>
+<li id="GUID-C6A3FA97-1F09-587E-9504-9685D8306B04"><p>Creating registrations </p> </li>
+<li id="GUID-A02F02C7-A903-53E0-A64E-F0B62C93A90F"><p>Forming and tearing
+down dialogs initiated by INVITE, REFER and SUBSCRIBE requests </p> </li>
+</ul>
+<section id="GUID-8D3D5FB3-6037-5956-B3F0-DB14BD1BB17B"><title>Architectural
+relationships</title> <p>The SIP Client API uses the client-server mechanism
+to interact with the SIP stack. This means more than one client can use the
+SIP stack at the same time. The calls to the SIP Client API are synchronous.
+The SIP Client API implements a set of callback functions to pass the events
+back to the application. </p> <p><b>Capability information</b> </p> <p>The
+following table describes the capabilities required to use the SIP Client
+API and the conditions in which they are required: </p> <table id="GUID-B3DCF31A-C6D5-58B9-87FA-B2CD3E0ABA1F">
+<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>
+<thead>
+<row>
+<entry>Capability </entry>
+<entry>Reason needed </entry>
+</row>
+</thead>
+<tbody>
+<row>
+<entry><p>NetworkServices </p> </entry>
+<entry><p>to send or receive SIP messages </p> </entry>
+</row>
+<row>
+<entry><p>WriteDeviceData </p> </entry>
+<entry><p>to create an instance of the <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> class </p> </entry>
+</row>
+<row>
+<entry><p>NetworkControl </p> <p>Location </p> <p>ReadDeviceData </p> </entry>
+<entry><p>to use the function <codeph>CSIPConnection::SetOptL()</codeph> </p> </entry>
+</row>
+</tbody>
+</tgroup>
+</table> <p><b>Extending the API</b> </p> <p>SIP Client API cannot be extended. </p> </section>
+<section id="GUID-E055BF09-9605-57E6-9502-CB3F4CAC29B8"><title>SIP Client
+API class structure</title> <ul>
+<li id="GUID-3E500E7D-ECB9-50F8-B996-A212EE294E68"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-581B8017-EAA0-59CB-A9CB-490370E0CEC9"> CSIP, MSIPObserver, CSIPConnection and MSIPConnectionObserver</xref> </p> </li>
+<li id="GUID-461F8201-ED85-582A-945C-7471F9BF27AA"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-0E726099-31C4-5DD4-9AEA-67765589F462">Registration services</xref> </p> </li>
+<li id="GUID-F69AEAB7-0E13-5673-B696-843957CC4C72"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-80CE8929-9DFD-5DCA-A929-662BD996223B"> SIP dialog associations</xref> </p> </li>
+<li id="GUID-BFE257A7-EF1A-58BF-A047-00E0B11B1FD3"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-B0D208E4-D1F9-5C5F-B937-11118E778074">Requests sent to, and received from, the network</xref> </p> </li>
+<li id="GUID-D0AC4583-B181-501C-A97A-63F094AD4046"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-0427709F-CD4B-5363-9377-10402B8A5819">SIP message related classes</xref> </p> </li>
+<li id="GUID-31ED307B-2285-5DE0-A83B-D0CB7A8C585D"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-4E4FAFCA-0BF6-510C-B8E3-28A83936A154">Automatically refreshing a SIP request</xref> </p> </li>
+<li id="GUID-B6E46736-A250-5064-B4F8-595A20025478"><p> <xref href="GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F.dita#GUID-A29FD82C-B3CC-5862-8DAB-1398A61D8B1F/GUID-B71BC486-18C2-5E71-965E-0881FBA9CE85">Managing HTTP digest security settings</xref> </p> </li>
+</ul> <p id="GUID-581B8017-EAA0-59CB-A9CB-490370E0CEC9"><b> CSIP, MSIPObserver,
+CSIPConnection and MSIPConnectionObserver </b> </p> <fig id="GUID-0834012C-083F-5FA0-B29D-E3E852165528">
+<image href="GUID-4381EA7F-BE75-5B43-BE97-C97D71D04377_d0e332416_href.png" placement="inline"/>
+</fig> <p>An application creates a single instance of the <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> class,
+and implements the callback functions defined by <xref href="GUID-C6FF4A83-0097-3A82-B4ED-802E1FEA05D1.dita"><apiname>MSIPObserver</apiname></xref>.
+The <codeph>CSIP</codeph> uses the <codeph>MSIPObserver</codeph> functions.
+The <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> class asks the supported security mechanisms and
+determines whether a <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> object exists for a
+given IAP. </p> <p>The <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> object creates an instance
+of <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> that allows you to send standalone SIP
+requests and ask for the state of the network connection. Responses are received
+through the <xref href="GUID-B889A3FD-3B14-3785-90AE-3546F0C9A5D4.dita"><apiname>MSIPConnectionObserver</apiname></xref> interface that defines
+a set of callback functions that an application must implement. </p> <p>An
+application can have many <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> objects, but each
+of them must have a different IAP. </p> <p id="GUID-0E726099-31C4-5DD4-9AEA-67765589F462"><b>Registration
+services</b> </p> <fig id="GUID-63E38B2E-975E-554C-8EDC-65B8BBA86838">
+<image href="GUID-E4543D60-A9D0-5121-9540-993BB15D3275_d0e332473_href.png" placement="inline"/>
+</fig> <p>An existing <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> is required to create
+an instance of <codeph>CSIPRegistrationBinding</codeph>. The <xref href="GUID-48AA01D5-CE7B-3C22-B2E0-529261121EC4.dita"><apiname>CSIPRegistrationBinding</apiname></xref> class
+provides services for registration, updating the registration, and deregistration.
+This class also provides instructions to the SIP stack to automatically refresh
+the registration, and to query and set the outbound proxy used by the registration. </p> <p id="GUID-80CE8929-9DFD-5DCA-A929-662BD996223B"><b> SIP dialog
+associations</b> </p> <fig id="GUID-4870BE80-44B6-50F0-B77E-73FEAD136304">
+<image href="GUID-17D1489B-F7F7-5CA7-9F81-850AA9ACEFEB_d0e332498_href.png" placement="inline"/>
+</fig> <p> <xref href="GUID-9841AF1A-B8CF-3BA1-8445-93064549AE8C.dita"><apiname>CSIPDialogAssocBase</apiname></xref> is the base class for SIP
+dialog associations, such as <xref href="GUID-B4A2FBBD-2B5F-3E64-800D-C4E9203679A8.dita"><apiname>CSIPInviteDialogAssoc</apiname></xref>, <xref href="GUID-9539CAEE-28AE-3134-8415-EEBCBCDA4D18.dita"><apiname>CSIPSubscribeDialogAssoc</apiname></xref>, <xref href="GUID-2E7EF887-ED59-3E8A-B9A2-686DF879A16C.dita"><apiname>CSIPReferDialogAssoc</apiname></xref> and <xref href="GUID-72F96612-A95C-3066-BFF0-2E288C945A2A.dita"><apiname>CSIPNotifyDialogAssoc</apiname></xref>. The <xref href="GUID-9841AF1A-B8CF-3BA1-8445-93064549AE8C.dita"><apiname>CSIPDialogAssocBase</apiname></xref> class
+is used to obtain the associated SIP dialog, for the associated <xref href="GUID-382BC1BE-3CF3-3E81-B1FF-341EEF2B67EA.dita"><apiname>CSIPDialog</apiname></xref> instance,
+and for sending a non-target Refresh request within the dialog. </p> <p> <b> Note: </b> The
+SIP Client API creates the <xref href="GUID-382BC1BE-3CF3-3E81-B1FF-341EEF2B67EA.dita"><apiname>CSIPDialog</apiname></xref> instance, it cannot
+be created by the application. </p> <p>If any of the <xref href="GUID-B4A2FBBD-2B5F-3E64-800D-C4E9203679A8.dita"><apiname>CSIPInviteDialogAssoc</apiname></xref>, <xref href="GUID-9539CAEE-28AE-3134-8415-EEBCBCDA4D18.dita"><apiname>CSIPSubscribeDialogAssoc</apiname></xref>, <xref href="GUID-2E7EF887-ED59-3E8A-B9A2-686DF879A16C.dita"><apiname>CSIPReferDialogAssoc</apiname></xref> and <xref href="GUID-72F96612-A95C-3066-BFF0-2E288C945A2A.dita"><apiname>CSIPNotifyDialogAssoc</apiname></xref> objects
+are associated, they are bound to an existing <xref href="GUID-382BC1BE-3CF3-3E81-B1FF-341EEF2B67EA.dita"><apiname>CSIPDialog</apiname></xref> object,
+or they can be used to create a new <codeph>CSIPDialog</codeph> object. </p> <p> <b>Note:</b> </p> <ul>
+<li id="GUID-6A085F6F-C243-53AD-B33C-F37D14DFE0A4"><p> <xref href="GUID-B4A2FBBD-2B5F-3E64-800D-C4E9203679A8.dita"><apiname>CSIPInviteDialogAssoc</apiname></xref> allows
+an application to initiate a dialog and to send <codeph>INVITE</codeph>,,<codeph>PRACK</codeph>,,<codeph>ACK</codeph>, <codeph>UPDATE,</codeph> and <codeph>BYE</codeph> requests related to the dialog. </p> </li>
+<li id="GUID-19C504F0-EAD5-524A-82E9-2D15BFA2A6D2"><p> <xref href="GUID-9539CAEE-28AE-3134-8415-EEBCBCDA4D18.dita"><apiname>CSIPSubscribeDialogAssoc</apiname></xref> allows
+an application to subscribe to different events by sending SUBSCRIBE and UNSUBSCRIBE
+requests. It also orders the SIP stack to automatically refresh the SUBSCRIBE
+request. </p> </li>
+<li id="GUID-C47B74D8-2251-5FCC-A356-1364EB61CF05"><p> <xref href="GUID-2E7EF887-ED59-3E8A-B9A2-686DF879A16C.dita"><apiname>CSIPReferDialogAssoc</apiname></xref> allows
+an application to define and send REFER requests. </p> </li>
+<li id="GUID-18AD2000-2A37-5CD9-8118-8B3322211D28"><p> <xref href="GUID-72F96612-A95C-3066-BFF0-2E288C945A2A.dita"><apiname> CSIPNotifyDialogAssoc</apiname></xref> allows
+an application to define and send NOTIFY requests. </p> </li>
+</ul> <p id="GUID-B0D208E4-D1F9-5C5F-B937-11118E778074"><b>Sent and received
+network requests</b> </p> <fig id="GUID-2E0C9020-1863-5644-BF7E-62B4DB9104D2">
+<image href="GUID-F5A82F61-B93A-5652-93A4-B9CE877B4D4A_d0e332635_href.png" placement="inline"/>
+</fig> <p>When a SIP request is sent to the network, the SIP Client API implementation
+creates a <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> object and returns it to
+the application. A <codeph>CSIPClientTransaction</codeph> object represents
+the SIP transaction and consists of the SIP request and the SIP response.
+After receiving a response, the application gets <xref href="GUID-13F32052-70BE-3B4D-9F8B-DF2DABB896B0.dita"><apiname>CSIPResponseElements</apiname></xref> from
+the <codeph>CSIPClientTransaction</codeph> object. <b>Note:</b> Some client
+transactions can also be cancelled or refreshed. </p> <p>When a SIP request
+is received from the network, it is passed to the application as a <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> object.
+The application gets <xref href="GUID-19FB031A-CFA7-3C67-A627-CFF501060AA5.dita"><apiname>CSIPRequestElements</apiname></xref> from the <codeph>CSIPServerTransaction</codeph> object.
+A <codeph>CSIPRequestElements</codeph> object describes the kind of SIP request
+received. After the application determines the type of response to send, it
+uses the <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> to send the responses. </p> <p> <xref href="GUID-93256B64-49C9-37F1-9A4E-72C521759749.dita"><apiname>CSIPTransactionBase</apiname></xref> is
+the base class for <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> and <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref>.
+It provides the functions to obtain the current state of the transaction and
+the transaction type. Some operations are only allowed when the transaction
+is in a certain state. <b>Note:</b> The SIP Client API creates instances of <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> and <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> and they cannot be created by the application. </p> <p id="GUID-0427709F-CD4B-5363-9377-10402B8A5819"><b>SIP
+message related classes</b> </p> <fig id="GUID-B99CF040-E91F-5281-8AAC-2151049C0EA8">
+<image href="GUID-6290D35A-7A41-5B9E-882A-E14F6D165ED7_d0e332712_href.png" placement="inline"/>
+</fig> <p>When a SIP request is sent to the network, the SIP Client API implementation
+creates a <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> object and returns it to
+the application. A <codeph>CSIPClientTransaction</codeph> object represents
+the SIP transaction and consists of the SIP request and the SIP response.
+After receiving a response the application gets <xref href="GUID-13F32052-70BE-3B4D-9F8B-DF2DABB896B0.dita"><apiname>CSIPResponseElements</apiname></xref> from
+the <codeph>CSIPClientTransaction</codeph> object. <b>Note:</b> Some client
+transactions can be cancelled or refreshed. </p> <p>When a SIP request is
+received from the network, it is passed to the application as a <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> object.
+The application gets <xref href="GUID-19FB031A-CFA7-3C67-A627-CFF501060AA5.dita"><apiname>CSIPRequestElements</apiname></xref> from the <codeph>CSIPServerTransaction</codeph> object.
+A <codeph>CSIPRequestElements</codeph> object describes the type of SIP request
+received. After the application determines the type of response to send, it
+uses the <codeph>CSIPServerTransaction</codeph> to send the responses. </p> <p> <xref href="GUID-93256B64-49C9-37F1-9A4E-72C521759749.dita"><apiname>CSIPTransactionBase</apiname></xref> is
+the base class for <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> and <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref>.
+It provides functions to obtain the current state of the transaction and the
+transaction type. Some operations are only allowed when the transaction is
+in a certain state. <b>Note:</b> The SIP Client API creates instances of <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> and <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> and they cannot be created by the application. </p> <p id="GUID-4E4FAFCA-0BF6-510C-B8E3-28A83936A154"><b> Automatically
+refreshing a SIP request</b> </p> <fig id="GUID-49ACB697-512C-5FCF-AD48-20D6AAB0FEFC">
+<image href="GUID-6B9E5B8D-E2F7-5972-ABFB-49F7F466EBBD_d0e332788_href.png" placement="inline"/>
+</fig> <p>The SIP stack automatically refreshes a SIP request using the <xref href="GUID-3C166C85-6E17-323B-9CD3-B3E2836DC1C3.dita"><apiname>CSIPRefresh</apiname></xref> object. <codeph>REGISTER</codeph>, <codeph>SUBSCRIBE</codeph> and a request outside the dialog are refreshed. After
+sending a refresh request, the application queries the state of the refresh
+from <codeph>CSIPRefresh</codeph>. </p> <p> <codeph>CSIPRefresh</codeph> provides
+functions for updating and terminating the refresh, for requests outside the
+dialog. The <xref href="GUID-48AA01D5-CE7B-3C22-B2E0-529261121EC4.dita"><apiname>CSIPRegistrationBinding</apiname></xref> and <xref href="GUID-9539CAEE-28AE-3134-8415-EEBCBCDA4D18.dita"><apiname>CSIPSubscribeDialogAssoc</apiname></xref> classes
+are used to update and terminate a refreshed <codeph>REGISTER</codeph> or <codeph>SUBSCRIBE</codeph>. </p> <p id="GUID-B71BC486-18C2-5E71-965E-0881FBA9CE85"><b> Managing HTTP digest security
+settings </b> </p> <fig id="GUID-7C296C1B-67E3-569F-A5E9-92A4F7922088">
+<image href="GUID-1704898B-7836-53C2-8743-F733836EDE7B_d0e332834_href.png" placement="inline"/>
+</fig> <p>An application must create an instance of the <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> class
+to use <codeph>CSIPHttpDigest</codeph>. The <xref href="GUID-F9FBAFBE-A895-3FD3-A526-604A6C9E035D.dita"><apiname>CSIPHttpDigest</apiname></xref> class
+manages HTTP digest security settings and contains only static functions. </p> </section>
+<section id="GUID-4195FAF9-D0D7-5046-BD62-9A314791BEFE"><title>Memory used</title> <p>After
+the <xref href="GUID-AFB2603A-8A35-3E70-8EC2-229C9726F00B.dita"><apiname>CSIP</apiname></xref> and <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> objects
+are created, most of the memory consumed is by <xref href="GUID-77CFD812-7238-3B84-80FF-475BD73C3506.dita"><apiname>CSIPMessageElements</apiname></xref>, <xref href="GUID-19FB031A-CFA7-3C67-A627-CFF501060AA5.dita"><apiname>CSIPRequestElements</apiname></xref> and <xref href="GUID-13F32052-70BE-3B4D-9F8B-DF2DABB896B0.dita"><apiname>CSIPResponseElements</apiname></xref> classes. <xref href="GUID-93256B64-49C9-37F1-9A4E-72C521759749.dita"><apiname>CSIPTransactionBase</apiname></xref> holds the most recent SIP
+response in a <xref href="GUID-13F32052-70BE-3B4D-9F8B-DF2DABB896B0.dita"><apiname>CSIPResponseElements</apiname></xref> object. When another
+response is received, the previous <xref href="GUID-13F32052-70BE-3B4D-9F8B-DF2DABB896B0.dita"><apiname>CSIPResponseElements</apiname></xref> object
+is deleted and a new one is created. </p> <p> <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> contains
+a <xref href="GUID-19FB031A-CFA7-3C67-A627-CFF501060AA5.dita"><apiname>CSIPRequestElements</apiname></xref> object until the SIP request is transferred
+to the server side of the SIP stack. <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> contains
+the SIP request as <xref href="GUID-19FB031A-CFA7-3C67-A627-CFF501060AA5.dita"><apiname>CSIPRequestElements</apiname></xref>. The application
+owns the <xref href="GUID-059F9C3A-EA04-3295-912F-50444F073CE7.dita"><apiname>CSIPClientTransaction</apiname></xref> and <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> objects.
+When the transaction terminates, the application deletes these objects to
+conserve memory. </p> <p>A non-<codeph>INVITE</codeph> <codeph>CSIPClientTransaction</codeph> is
+deleted when it has received a final response or when the <codeph>ErrorOccured()</codeph> callback
+is called. A non-<codeph>INVITE</codeph> <codeph>CSIPServerTransaction</codeph> is
+deleted after the application sends a final response. </p> <p>The <codeph>INVITE</codeph> related
+transactions are deleted if the <codeph>ErrorOccured()</codeph> callback function
+is called. These transactions behave differently because of the presence of
+an <codeph>ACK</codeph>. </p> <p>When the application sends a 2xx response
+to an <codeph>INVITE</codeph> related <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref>,
+it enters the <xref href="GUID-93256B64-49C9-37F1-9A4E-72C521759749.dita#GUID-93256B64-49C9-37F1-9A4E-72C521759749/GUID-DF7E4DCE-1F6D-3F2A-A638-5516A733AA9D"><apiname>CSIPTransactionBase::ETerminated</apiname></xref> state and
+it is deleted at this point. A new <xref href="GUID-7E54C95E-5155-30B1-8169-A59778774403.dita"><apiname>CSIPServerTransaction</apiname></xref> object
+receives the ACK. </p> <p>When the application sends an <codeph>INVITE</codeph> request
+and the <codeph>CSIPClientTransaction</codeph> receives a 2xx response, the
+transaction enters the <codeph>CSIPTransactionBase::ETerminated</codeph> state.
+The associated <codeph>CSIPClientTransaction</codeph> must not be deleted
+as it is required to send the <codeph>ACK</codeph> and also to receive the <xref href="GUID-B889A3FD-3B14-3785-90AE-3546F0C9A5D4.dita#GUID-B889A3FD-3B14-3785-90AE-3546F0C9A5D4/GUID-2E76BDA0-CE87-3538-A791-963A90230FD4"><apiname>MSIPConnectionObserver::InviteCompleted()</apiname></xref> callback.
+An <codeph>INVITE</codeph> related <codeph>CSIPClientTransaction</codeph> must
+be deleted only after a <codeph>MSIPConnectionObserver::InviteCompleted</codeph> or <xref href="GUID-D14D6845-1C5E-3C15-8310-574A2A8C6C95.dita#GUID-D14D6845-1C5E-3C15-8310-574A2A8C6C95/GUID-DED382FB-A6D5-37D7-B8E4-05262F690068"><apiname>MSIPConnectionObserver
+::ErrorOccured</apiname></xref> event is received, or if the state of the associated <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita"><apiname>CSIPConnection</apiname></xref> goes
+to <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita#GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94/GUID-68DD22DC-67E4-387B-BBE9-B9B96D9C9016"><apiname>CSIPConnection::EInactive</apiname></xref> or <xref href="GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94.dita#GUID-2A070F4D-A35B-3505-BE86-E6C7A2F27B94/GUID-5963A947-BD5C-3B34-9D10-2CB5DC413774"><apiname>CSIPConnection::EUnavailable</apiname></xref>. </p> </section>
</conbody></concept>
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