Mercurial Mercurial > oss > FCL > sftools > depl > docscontent / diff
summary | shortlog | changelog | graph | tags | bookmarks | branches | files | changeset | file | latest | revisions | annotate | diff | comparison | raw | help
Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Symbian3/PDK/Source/GUID-18C39927-625C-5B24-919F-469FCBCD501D.dita
changeset 1 25a17d01db0c
child 3 46218c8b8afa 
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/PDK/Source/GUID-18C39927-625C-5B24-919F-469FCBCD501D.dita	Fri Jan 22 18:26:19 2010 +0000
@@ -0,0 +1,158 @@
+<?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-18C39927-625C-5B24-919F-469FCBCD501D" xml:lang="en"><title>BCA2
+API Overview</title><shortdesc>Explains the second Baseband Channel Abstraction design (BCA2). </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<section id="GUID-8EA6D7A7-26A8-5B96-ADD7-E01E86B05329"><title>Required background</title> <p>You
+should be familiar with the following areas: </p> <ul>
+<li id="GUID-CCE01846-276A-5EB9-9876-DBBC90BD31A7"><p>architecture of device
+drivers in Symbian platform (see <xref href="GUID-8D80AA51-5108-5D4B-B6B9-7FA47570AB89.dita">Device
+Drivers Concepts</xref>) </p> </li>
+<li id="GUID-8DAA8E32-B216-5279-A4AE-4435596F5517"><p>general principles of
+a telephony stack (see <xref href="GUID-FA5A24BE-F4AF-5EC3-8969-6184A5A5BBFA.dita">Cellular
+Baseband Services</xref>) </p> </li>
+<li id="GUID-01DF1F36-5E88-5365-82E3-6601FBFE5F48"><p>networking and telephony
+components. </p> </li>
+</ul> </section>
+<section id="GUID-679587F9-CD73-51C2-8D7E-AE5817533660"><title>Key concepts
+and terms</title> <p> </p> <dl>
+<dlentry>
+<dt>BCA</dt>
+<dd><p>Baseband Channel Adapter </p> </dd>
+</dlentry>
+<dlentry>
+<dt>LDD</dt>
+<dd><p>Logical device driver (see <xref href="GUID-8D80AA51-5108-5D4B-B6B9-7FA47570AB89.dita">Device
+Drivers Concepts</xref>) </p> </dd>
+</dlentry>
+<dlentry>
+<dt>PPP</dt>
+<dd><p>Point-to-Point Protocol (see <xref href="GUID-E18F402A-6478-5B24-8DC0-33989FC5FD43.dita">What
+is PPP?</xref>) </p> </dd>
+</dlentry>
+<dlentry>
+<dt>HDLC</dt>
+<dd><p>High-level Data Link Control </p> </dd>
+</dlentry>
+<dlentry>
+<dt>ISDN</dt>
+<dd><p>Integrated Services Digital Network </p> </dd>
+</dlentry>
+<dlentry>
+<dt>ECUART</dt>
+<dd><p>Serial RS232 driver for Symbian OS. UART means Universal Asynchronous
+Receiver/Transmitter. </p> </dd>
+</dlentry>
+<dlentry>
+<dt>C32</dt>
+<dd><p>Serial Communications Server in Symbian OS (see <xref href="GUID-9B83CDD4-FC94-51A0-AC67-CD04BCAFEF08.dita">Serial
+Communications Server</xref>) </p> </dd>
+</dlentry>
+</dl> </section>
+<section id="GUID-FEB0738E-8AB9-48DD-8648-493AC70258A0"><title>Introduction</title> <p>The Baseband Channel Adapter (BCA)
+provides a telephony-specific abstraction of the baseband driver. </p> <p>You
+implement your BCA components depending on the level of abstraction you require,
+providing a standard interface to the component above it in the Communications
+stack. You can also stack BCA components for more flexibility. </p> <p>Performance
+is a critical requirement for the Comms Data Plane. To improve throughput,
+update your BCA components and your link layer protocol plugins to use the <xref href="GUID-55442FD0-FD97-3FA3-A61A-C1288C4D5670.dita"><apiname>MBca2</apiname></xref> interface. </p> </section>
+<section id="GUID-5D32EEFF-FFF5-51DE-AF53-F182A4E49F9D"><title>Architecture</title> <p>This
+topic focuses on a general case where there is one BCA component between the
+driver and the lower layer of the Data Plane. In the case of a stack of BCA
+components, the same design is repeated between each BCA layer. </p> <p>In
+a "pull" communication model, the destination requests data from the source.
+Data transfer happens when the destination is ready. In a "push" model, the
+source provides data to the destination : data transfer happens when the source
+is ready. </p> <p>BCA2 is based on a "push" architecture. The link layer component
+registers with the BCA component. The BCA component provides the data to its
+registered clients as soon as the data becomes available. </p> <p>The API
+is split into five classes to separate control flow and data flow methods. </p> <fig id="GUID-699CB340-3DBB-50F5-8555-D4E2609BDECC">
+<title>              MBca2 design            </title>
+<image href="GUID-0B45D491-F88A-5036-A51C-9BFD6DB574D5_d0e62608_href.png" placement="inline"/>
+</fig> <p>Moreover, the <xref href="GUID-55442FD0-FD97-3FA3-A61A-C1288C4D5670.dita"><apiname>MBca2</apiname></xref> interface
+relies on shared buffers instead of regular buffers. Using shared buffers
+avoids data copies between different layers of the stack. For more information,
+see <xref href="GUID-A248C2C0-5F64-5484-85B2-57C86E3499E1.dita">Memory Management
+in the Communications Framework</xref>. </p> </section>
+<section id="GUID-5826984F-EAFA-5EDC-9C39-3966C89373A2"><title>APIs</title> <p><b>BCA component</b> </p> <table id="GUID-049AA111-6F8D-52F3-9681-0746FD0E4E9B">
+<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>
+<thead>
+<row>
+<entry>API</entry>
+<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+<entry><p> <xref href="GUID-55442FD0-FD97-3FA3-A61A-C1288C4D5670.dita"><apiname>MBca2</apiname></xref>  </p> </entry>
+<entry><p>Provides startup and shutdown methods. </p> </entry>
+</row>
+<row>
+<entry><p> <xref href="GUID-55442FD0-FD97-3FA3-A61A-C1288C4D5670.dita"><apiname>MLowerDataSender</apiname></xref>  </p> </entry>
+<entry><p>Provides the <codeph>Send()</codeph> method, which takes a <xref href="GUID-55442FD0-FD97-3FA3-A61A-C1288C4D5670.dita"><apiname>RCommsBufChain</apiname></xref> as its parameter
+and is called by the link layer component whenever it needs to send data to
+the baseband (through the BCA component). </p> </entry>
+</row>
+<row>
+<entry><p> <xref href="GUID-55442FD0-FD97-3FA3-A61A-C1288C4D5670.dita"><apiname>MLowerControl</apiname></xref>  </p> </entry>
+<entry><p>Provides methods for downwards flow control and control options.
+The control options depend on your implementations of the BCA, the driver
+and the link layer component. For examples of control options, see the <xref href="GUID-E054E7F6-3918-5F76-8489-D5CFC9EE257A.dita">BCA2 Control Options</xref> reference
+page. </p> </entry>
+</row>
+</tbody>
+</tgroup>
+</table> <p><b>Link
+layer component</b> </p> <table id="GUID-D33F08E6-3192-56C8-9989-82B82F7024AC">
+<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>
+<thead>
+<row>
+<entry>API</entry>
+<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+<entry><p> <xref href="GUID-55442FD0-FD97-3FA3-A61A-C1288C4D5670.dita"><apiname>MUpperDataReceiver</apiname></xref>  </p> </entry>
+<entry><p>Provides the <codeph>Process()</codeph> method, which takes a <xref href="GUID-55442FD0-FD97-3FA3-A61A-C1288C4D5670.dita"><apiname>RCommsBufChain</apiname></xref> as its parameter
+and is called by the lower BCA component whenever data is available, in order
+to push the data to the upper layer. </p> </entry>
+</row>
+<row>
+<entry><p> <xref href="GUID-55442FD0-FD97-3FA3-A61A-C1288C4D5670.dita"><apiname>MUpperDataControl</apiname></xref>  </p> </entry>
+<entry><p>Provides methods for error management and upwards flow control. </p> </entry>
+</row>
+</tbody>
+</tgroup>
+</table> <p>In the case of stacked BCA components, these APIs are implemented
+by the upper BCA component. </p> </section>
+<section id="GUID-71B6234B-470C-5241-A899-679709B91AE0"><title>Typical uses</title> <p>Device
+driver developers implement the BCA2 design in the Networking stack (BCA components
+and link layer protocol plugins). </p> <p>The following three diagrams show
+common BCA components and illustrate how they integrate with the Communications
+Framework. For definition of the abbreviations used in the diagrams, see the <xref href="GUID-18C39927-625C-5B24-919F-469FCBCD501D.dita#GUID-18C39927-625C-5B24-919F-469FCBCD501D/GUID-679587F9-CD73-51C2-8D7E-AE5817533660">Key
+concepts and terms</xref> section. </p> <fig id="GUID-4B18CDAD-FDF3-5AF2-8B7C-85DC77C3E5FE">
+<title>              Use case for BCA: IP communication through the serial
+port            </title>
+<image href="GUID-0F5C8DA1-EF91-588B-A917-350793DA03A5_d0e62806_href.png" placement="inline"/>
+</fig> <fig id="GUID-1297D10A-59C2-5C15-877D-7CF94B667878">
+<title>              Use case for BCA: PPP communication through the serial
+port            </title>
+<image href="GUID-760222AA-59F0-58E6-A494-F9CB6D739960_d0e62814_href.png" placement="inline"/>
+</fig> <fig id="GUID-4A636F57-AF70-5646-A957-4B4F4AD5EA70">
+<title>              Use case for BCA: PPP communication over Ethernet   
+        </title>
+<image href="GUID-96F5CB06-F1C2-5F37-B5B8-DA8C086B73AA_d0e62822_href.png" placement="inline"/>
+</fig> </section>
+</conbody><related-links>
+<link href="GUID-E054E7F6-3918-5F76-8489-D5CFC9EE257A.dita"><linktext>BCA2 Control
+Options</linktext></link>
+</related-links></concept>
\ No newline at end of file
FCL/sftools/depl/docscontent