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<concept id="GUID-C2CF49A8-E1AC-565B-8C7F-28C89D59600F" xml:lang="en"><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 platform 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 href="http://webapp.etsi.org/exchangefolder/ts_124008v032000p.pdf" scope="external">09.61</xref> and <xref href="http://www.3gpp.org/ftp/Specs/archive/24_series/24.008/" scope="external">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 id="GUID-894B301D-A3B6-494B-84A4-1D5508E63F4D"><title>See also</title> <p> <xref href="GUID-5491D859-C348-5C39-AAE0-783A3A4B69B3.dita">Architecture</xref> </p> </section>
</conbody></concept>