--- /dev/null
+<?xml version="1.0" encoding="UTF-8"?>
+<section id="orte-internals">
+ <title>ORTE Implementation Issues</title>
+
+ <para>
+ ORTE is network middleware for distributed, real-time application development
+ that uses the real-time, publish-subscribe model. The middleware is available
+ for a variety of platforms including RTAI, RTLinux, Windows, and a several
+ versions of Unix. The compilation system is mainly based on autoconf.
+ </para>
+
+ <para>
+ ORTE is middleware composed of a database, and tasks.
+ On the top of ORTE architecture is application interface (API). By using API
+ users should write self application. The tasks perform all of the message
+ addressing serialization/deserialization, and transporting. The ORTE components
+ are shown in <xref linkend="cap:orte_internal_architecture"/>
+ </para>
+ <figure id="cap:orte_internal_architecture">
+ <title>ORTE Architecture
+ </title>
+ <mediaobject>
+ <imageobject>
+ <imagedata align="center" fileref="&orte_internal_architecture_img;"
+ format="EPS" scale="35" srccredit="OCERA CTU 2004" />
+ </imageobject>
+ </mediaobject>
+ </figure>
+
+
+ <para>
+ The RTPS protocol defines two kinds of Applications:
+ </para>
+
+ <itemizedlist>
+ <listitem>
+ <para>
+ <emphasis role="bold">Manager:</emphasis>
+ The manager is a special Application that helps applications automatically
+ discover each other on the Network.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">ManagedApplication:</emphasis>
+ A ManagedApplication is an Application that is managed by one or more
+ Managers. Every ManagedApplication is managed by at least one Manager.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ The manager is mostly designed like separate application. In RTPS architecture
+ is able to create application which contains manager and managedapplication, but
+ for easy managing is better split both. The ORTE contains a separate instance
+ of manager located in directory <filename>orte/manager</filename>.
+ </para>
+
+ <para>The manager is composed from five kinds of objects:</para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ <emphasis role="bold">WriterApplicationSelf:</emphasis>
+ through which the Manager provides information about its own parameters
+ to Managers on other nodes.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">ReaderManagers:</emphasis>
+ CSTReader through which the
+ Manager obtains information on the state of all other Managers on the
+ Network.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">ReaderApplications:</emphasis>
+ CSTReader which is used for the registration of local and remote
+ managedApplications.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">WriterManagers:</emphasis>
+ CSTWriter through which the Manager will send the
+ state of all Managers in the Network to all its managees.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">WriterApplications:</emphasis>
+ CSTWriter through which the Manager will
+ send information about its managees to other Managers in the Network.
+ </para>
+ </listitem>
+ </itemizedlist>
+
+ <para>
+ A Manager that discovers a new ManagedApplication
+ through its readerApplications must decide whether it must manage this
+ ManagedApplication or not. For this purpose, the attribute
+ managerKeyList of the Application is used. If one of the
+ ManagedApplication's keys (in the attribute managerKeyList) is equal
+ to one of the Manager's keys, the Manager accepts the Application as
+ a managee. If none of the keys are equal, the managed application is
+ ignored. At the end of this process all Managers have discovered their
+ managees and the ManagedApplications know all Managers in the Network.
+ </para>
+
+ <para>The managedApplication is composed from seven kinds of objects:</para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ <emphasis role="bold">WriterApplicationSelf:</emphasis>
+ a CSTWriter through which the ManagedApplication registers
+ itself with the local Manager.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">ReaderApplications:</emphasis>
+ a CSTReader through which the ManagedApplication receives
+ information about another ManagedApplications in the network.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">ReaderManagers:</emphasis>
+ a CSTReader through which the ManagedApplication receives
+ information about Managers.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">WriterPublications:</emphasis>
+ CSTWriter through which the Manager will send the
+ state of all Managers in the Network to all its managees.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">ReaderPublications:</emphasis>
+ a Reader through which the Publication receives information
+ about Subscriptions.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">WriterSubscriptions:</emphasis>
+ a Writer that provides information about Subscription to
+ Publications.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis role="bold">ReaderSubscriptions:</emphasis>
+ a Reader that receives issues from one or more instances of
+ Publication, using the publish-subscribe service.
+ </para>
+ </listitem>
+ </itemizedlist>
+
+ <para>
+ The ManagedApplication has a special CSTWriter writerApplicationSelf. The
+ Composite State (CS) of the ManagedApplication's writerApplicationSelf
+ object contains only one NetworkObject - the application itself. The
+ writerApplicationSelf of the ManagedApplication must be configured to
+ announce its presence repeatedly and does not request nor expect
+ acknowledgments.
+ </para>
+ <para>
+ The ManagedApplications now use the CST Protocol between the
+ writerApplications of the Managers and the readerApplications of the
+ ManagedApplications in order to discover other ManagedApplications in
+ the Network. Every ManagedApplication has two special CSTWriters,
+ writerPublications and writerSubscriptions, and two special CSTReaders,
+ readerPublications and readerSubscriptions.
+ </para>
+ <para>
+ Once ManagedApplications have discovered each other, they use the
+ standard CST protocol through these special CSTReaders and CSTWriter to
+ transfer the attributes of all Publications and Subscriptions in the
+ Network.
+ </para>
+
+ <para>The ORTE stores all data in local database per application. There isn't
+ central store where are data saved. If an application comes into communication,
+ than will be created local mirror of all applications parameters.
+ Parts of internal structures are shown in <xref linkend="cap:orte_attributes"/>.
+ </para>
+ <figure id="cap:orte_attributes">
+ <title>ORTE Internal Attributes
+ </title>
+ <mediaobject>
+ <imageobject>
+ <imagedata align="center" fileref="&orte_attributes_img;"
+ format="EPS" scale="35" srccredit="OCERA CTU 2004" />
+ </imageobject>
+ </mediaobject>
+ </figure>
+
+ <para>
+ Following example shows communication between two nodes (N1, N2).
+ There are applications running on each node - MA1.2 on node
+ N1 and MA2.1, MA2.2 on node N2. Each node has it own manager (M1, M2). The
+ example shows, what's happen when a new application comes into communication
+ (MA1.1).
+ </para>
+
+ <orderedlist>
+ <listitem><para>
+ MA1.1 introduces itself to local manager M1
+ </para></listitem>
+ <listitem><para>
+ M1 sends back list of remote managers Mx and other local applications MA1.x
+ </para></listitem>
+ <listitem><para>
+ MA1.1 is introduced to all Mx by M1
+ </para></listitem>
+ <listitem><para>
+ All remote MAs are reported now to M1.1
+ </para></listitem>
+ <listitem><para>
+ MA1.1 is queried for self services (publishers and subscriberes) from others MAx.
+ </para></listitem>
+ <listitem><para>
+ MA1.1 asks for services to others MAx.
+ </para></listitem>
+ <listitem><para>
+ All MAs know information about others.
+ </para></listitem>
+ </orderedlist>
+
+ <para>
+ The corresponding publishers and subscribers with matching Topic
+ and Type are connected and starts their data communication.
+ </para>
+
+ <figure id="cap:orte_rtps_communication">
+ <title>RTPS Communication among Network Objects
+ </title>
+ <mediaobject>
+ <imageobject>
+ <imagedata align="center" fileref="&orte_rtps_communication_img;"
+ format="EPS" scale="35" srccredit="OCERA CTU 2004" />
+ </imageobject>
+ </mediaobject>
+ </figure>
+
+</section>
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