<concept xml:lang="en" id="GUID-C2CF49A8-E1AC-565B-8C7F-28C89D59600F"><title>What is the Packet Context ?</title><shortdesc>The packet context encapsulate the functions related to the context of a packet switched network connection. The context of a connection relates to factors such as the protocol type, the access point to the network and the DNS and authentication parameters. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody><p>The context is associated with a particular <xref href="GUID-6C557DE7-160B-5B90-B017-AD8762F6B8A9.dita">packet service</xref>. </p> <p>Contexts for each network type are supported by different member classes in the <xref href="GUID-1CD9122E-B077-39FD-8CAE-45A6AF8F345F.dita"><apiname>RPacketContext</apiname></xref>: </p> <ul><li id="GUID-C383F0B1-0736-57B4-9CC9-EE837031DA85"><p> <xref href="GUID-1CD9122E-B077-39FD-8CAE-45A6AF8F345F.dita"><apiname>RPacketContext::TContextConfigGPRS</apiname></xref>, </p> </li> <li id="GUID-06926496-F4CA-5A5E-9B64-598BB5E8367E"><p> <xref href="GUID-1CD9122E-B077-39FD-8CAE-45A6AF8F345F.dita"><apiname>RPacketContext::TContextConfigR99_R4</apiname></xref> (from v7.0s onwards) </p> </li> <li id="GUID-F939554B-77DA-55C0-9271-4CB40D73BD76"><p> <xref href="GUID-1CD9122E-B077-39FD-8CAE-45A6AF8F345F.dita"><apiname>RPacketContext::TContextConfigCDMA</apiname></xref>. </p> </li> </ul> <p>Symbian OS provides the authentication parameters to support CHAP and PAP authentication methods. Previously only PAP authentication was supported. The CHAP authentication is more secure than the PAP authentication. The additional functions are: </p> <ul><li id="GUID-520F5D86-B5A3-5588-A981-74130C3D748A"><p>Point to Point Protocol (PPP) authentication parameters, that is the CHAP and PAP parameters to support authentication access with the Gateway GPRS Support Node (GGSN) and Authentication Authorization and Accounting (AAA) systems. It is up to the client to decide which mode of authentication to use. </p> </li> <li id="GUID-C2AC0BA5-3670-535A-8EB3-9266AF10311F"><p>CHAP authentication can get the Domain Name System (DNS) server name parameters like primary DNS and secondary DNS. The DNS server name is required in the authentication process. AAA may deliver DNS IP addresses to the network, so the Packet Data API supports delivering these addresses to the client. For more information see GSM Standards <xref scope="external" href="http://webapp.etsi.org/exchangefolder/ts_124008v032000p.pdf">09.61</xref> and <xref scope="external" href="http://www.3gpp.org/ftp/Specs/archive/24_series/24.008/">24.008</xref>. </p> </li> <li id="GUID-88370C4C-3444-557E-B4AE-EA51A5A97ABB"><p>The authentication can be used for both the primary and secondary contexts. A primary context configuration is set without reference to another context. Secondary contexts are created from an existing context that can be a primary or secondary context. </p> </li> </ul> <p>This API is implemented by <xref href="GUID-1CD9122E-B077-39FD-8CAE-45A6AF8F345F.dita"><apiname>RPacketContext</apiname></xref>. </p> <section id="GUID-39AAFDFC-501D-571C-9247-CDC3F5ABBF5E"><title>Packet context functions</title> <p>The <xref href="GUID-1CD9122E-B077-39FD-8CAE-45A6AF8F345F.dita"><apiname>RPacketContext</apiname></xref> API functions enable the clients to do the following: </p> <ul><li id="GUID-269C64FE-7EFB-5179-AFBB-93FB79EA83DD"><p>Obtain a secondary packet context from an existing packet. The second packet uses the same context information. The Quality of Service information is not used. </p> </li> <li id="GUID-5B469031-4C8C-57E1-A347-FDE932F6233A"><p>Configure the Quality of Service specifications of Release99 and Release4 in the packet context. </p> </li> <li id="GUID-F4E3E8C2-87D0-5587-A776-ACA5A4EDF35D"><p>Modify the negotiated QoS of an active context. </p> </li> <li id="GUID-C4212719-F29A-5143-8658-4849C175AE3F"><p>Add, remove and change the packet filters in the Traffic Flow template of a context. The clients can also create and delete the Traffic Flow templates. </p> </li> <li id="GUID-B07C16B0-52C8-5B14-A0FA-7B3E03BD9BD2"><p>Discover context information for a network interface (NIF) level. </p> </li> <li id="GUID-21A4445A-94D7-5EF1-802A-022BD493614E"><p>Retrieve the current packet network release mode to receive roaming notification between the release modes. </p> </li> </ul> </section> <section><title>See also</title> <p> <xref href="GUID-5491D859-C348-5C39-AAE0-783A3A4B69B3.dita">Architecture</xref> </p> </section> </conbody></concept>