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<concept xml:lang="en" id="GUID-BD8446C5-3ADE-59A6-A13A-A5482D6FC56F"><title>Connection Management</title><prolog><metadata><keywords/></metadata></prolog><conbody><p>This topic introduces the concept of Connection Management and the APIs needed to perform Connection Management operations. The APIs discussed include <xref href="GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD.dita"><apiname>RConnection</apiname></xref> and <xref href="GUID-B16CAD6D-85B1-3482-AAC0-9BADEDB6ABDD.dita"><apiname>RHostResolver</apiname></xref>. </p> <p>The RConnection API provides: </p> <ul><li id="GUID-395ABFCE-2A51-5205-B3FF-F85C882AF761"><p>an interface for actively creating and managing connections </p> </li> <li id="GUID-C3A61C1A-72DF-5304-9758-F6C298DF93AD"><p>facilities that are not available when creating connections by other methods. Such facilities include support for multihoming. </p> </li> </ul> <p>Introduced with the <keyword>multihoming</keyword> functionality, which allows multiple Circuit/Packet Switched Data connections to be active. </p> <p><b>Implementation </b> </p> <p>The connection management API is implemented by <xref href="GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD.dita"><apiname>RConnection</apiname></xref>. </p> <p> <xref href="GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD.dita"><apiname>RConnection</apiname></xref> objects are implemented as sub-sessions to the <xref href="GUID-EF29C1D7-B1E5-370F-AE37-66231A6BE449.dita"><apiname>RSocketServ</apiname></xref>. </p> <p><b>Connections and subconnections </b> </p> <p>An RConnection is the handle for an application onto an underlying interface. (But there may be a number of RConnections per interface). </p> <p>Technologies such as W-CDMA and later releases of GPRS are capable of establishing multiple subconnections within a connection. This is supported by the management interface. </p> <p>Note that all subconnections within a connection will have certain parameters in common, such as the Access Point Name in the case of GPRS and WCDMA. However, each subconnection may have a different Quality-of-Service. </p> <p><b>Guidelines for use </b> </p> <p> <codeph>RConnection</codeph> s need to be opened on an existing socket server session, <xref href="GUID-EF29C1D7-B1E5-370F-AE37-66231A6BE449.dita"><apiname>RSocketServ</apiname></xref>. </p> <p>In the API as a whole, there is an important distinction made between an <codeph>RConnection</codeph> object which has been newly opened on an socket server session but not yet associated with an underlying interface on the server, and one which is opened and associated. There are certain operations that require a <codeph>RConnection</codeph> object to be in the associated state to work successfully. The <xref href="GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD.dita#GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD/GUID-CB62E838-A380-309C-8B08-1F804EDB4387"><apiname>RConnection::Start()</apiname></xref> and <xref href="GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD.dita#GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD/GUID-EAB8B0B1-0F5B-31E5-BFD6-B3AE1181868E"><apiname>RConnection::Attach()</apiname></xref> methods are used to associate an <codeph>RConnection</codeph> object with an interface. </p> <p>There is no restriction on the number of <codeph>RConnection</codeph> objects per socket server session. It is also possible for several <codeph>RConnection</codeph> objects to refer to the same underlying interface. For example, several applications, each with its own socket server session and <codeph>RConnection</codeph> object, could refer to the same underlying interface. It is also technically possible for the said <codeph>RConnection</codeph> objects to be on the same socket server session, though this may be somewhat redundant. </p> <p>Rather like <xref href="GUID-D4F08503-F1EF-3531-9C3C-4AF24A6255F0.dita"><apiname>RSocket</apiname></xref> /<xref href="GUID-B16CAD6D-85B1-3482-AAC0-9BADEDB6ABDD.dita"><apiname>RHostResolver</apiname></xref> objects, an individual <codeph>RConnection</codeph> object is not designed to be used by multiple clients simultaneously (i.e. have multiple requests outstanding on it from different clients). </p> <p>Although <codeph>RConnection</codeph> objects are automatically closed when the corresponding socket server session is closed, appropriate use of <codeph>CleanupClosePushL(RConnection&amp;)</codeph> is more likely to ensure proper operation. </p> <p> <xref href="GUID-D4F08503-F1EF-3531-9C3C-4AF24A6255F0.dita"><apiname>RSocket</apiname></xref> and <xref href="GUID-B16CAD6D-85B1-3482-AAC0-9BADEDB6ABDD.dita"><apiname>RHostResolver</apiname></xref> objects can be associated with an <codeph>RConnection</codeph> object. In this case, data will flow over the same underlying interface as the <codeph>RConnection</codeph> to which they have been associated. For this to work, the <codeph>RSocket/RHostResolver/RConnection</codeph> objects must all be on the same socket server session, and the <codeph>RConnection</codeph> object must have been previously opened and active (i.e. associated with an underlying interface). </p> <section><title>Connection Management functionality</title> <p> <codeph>RConnection</codeph> provides clients with the following functionality: </p> <ul><li id="GUID-882DB251-213D-58BF-9398-9ADC68341298"><p>Opening and closing the connection </p> </li> <li id="GUID-E20078EE-FE93-5452-877B-C3F7985142FD"><p>Starting a connection, which means associating it with a new underlying interface </p> </li> <li id="GUID-FBBB3514-280E-5989-AC76-B81DD8CAC8B8"><p>Attaching the <codeph>RConnection</codeph> instance to an existing interface </p> </li> <li id="GUID-BB58A700-B58C-5C26-BD67-688EE0CF55C2"><p>Stopping the connection, which means disassociating it from the underlying interface </p> </li> <li id="GUID-A74BD98D-F3A7-5FE4-9F74-60AC2E1FBB78"><p>Obtaining progress information and notification during connection start-up </p> <p>This is useful because the process of dialling an ISP, logging in and starting network protocols can be quite lengthy, taking up to a minute in some cases. In addition, the application can get the last error which occurred in setting up the connection. </p> <p> </p> </li> <li id="GUID-9AAABE2A-3FB0-5B63-948F-2B3112683B0C"><p>Notifying when subconnections come up and go down </p> </li> <li id="GUID-418DFF66-415A-510D-AB86-1090EE0DC6B8"><p>Notifying when there is a service change for the connection </p> </li> <li id="GUID-CF7D3A21-0A1F-537B-AF50-4EDDBB931557"><p>Notifying when a given amount of data has been sent or received on a connection or subconnection </p> </li> <li id="GUID-E192532A-F857-5869-B5E0-D657AAFC8290"><p>Reading CommDB fields specific to an active connection </p> </li> <li id="GUID-1A83A7BD-FA23-5F4F-8D28-A0A24481DB9F"><p>Collecting statistical information on the network connection and subconnections. A UI component can display the collected statistical information in order to allow the user to examine the status of connections. The information that can be gathered is the following: </p> <ul><li id="GUID-AF90F93C-DA10-539F-842A-34337C51427F"><p>All available internet access point names and internet access point 'friendly' names as appropriate for each network (GPRS/UMTS) connection </p> </li> <li id="GUID-66B29945-C319-5E56-ABCA-301188643CDB"><p>Enumerating the currently active connections and subconnections </p> </li> <li id="GUID-8E888149-A79D-5608-9875-9753CEE59EE9"><p>The current status of all network connections e.g. active/suspended </p> </li> <li id="GUID-B1125663-747F-5F8C-927F-94AB17482FE5"><p>The amount of data (in bytes) transferred uplink and downlink by the network connection and subconnections </p> </li> <li id="GUID-E00B23A4-E91B-54E7-9AE1-429E19C520AB"><p>The amount of time each network connection has been active (in seconds) </p> </li> <li id="GUID-7AC5AC0D-9147-52A5-A427-B5D798D9A119"><p>The current status of the connection and subconnections with respect to data transfer, i.e. active/inactive </p> </li> <li id="GUID-AD4C0A7A-E48E-513F-806A-40934415D42B"><p>The Quality of Service profile associated with each Packet Data Protocol (GPRS/UMTS) context, e.g. low/medium/high </p> </li> </ul> </li> </ul> </section> <section><title>Historical Note</title> <p>Symbian OS 7.0S introduced the RConnection API. The RConnection API replaces the <xref href="GUID-DB9E15BA-BA79-3473-98F0-CF3FAF0016C4.dita"><apiname>RNif</apiname></xref>, <xref href="GUID-4838E090-0184-3153-A1A3-5C277F64E2C2.dita"><apiname>RGenericAgent</apiname></xref> and <xref href="GUID-495456DE-8C19-35FD-8555-5C321DAFDF78.dita"><apiname>RNifMonitor</apiname></xref> APIs used for connection startup. </p> </section> </conbody><related-links><link href="GUID-5CFC075C-8F53-5E1B-A111-C6F4567DFD1E.dita"><linktext>RConnection API Summary

                Reference</linktext> </link> </related-links></concept>