ATG Application Between Session

You can run multiple ATG applications in the form of WAR files within a single EAR. In this case, you should share session-scoped Nucleus components so that your application will always have access to the same instance of session scoped components.

When multiple web applications exist in the ATG EAR file, one of them must be designated as the parent application. Being the parent means that that application’s session ID is used as the basis for creating the ATG session scope root.your web applications should define the atg.session.parentContextName and atg.dafear.bootstrapContextName parameters in their web.xml to point to the parent web-application as shown:

   atg.session.parentContextName

   /dyn

   atg.dafear.bootstrapContextName

   /dyn

   The name of the DAF bootstrap WAR context.

The context path the context-param points to must be for a WAR file with the SessionNameContextServlet defined in its web.xml:

   SessionNameContextServlet

   atg.nucleus.servlet.SessionNameContextServlet

  

Note : that there can be only one parent web application specified per EAR file. Therefore, if you change the parent application, be sure to set the context-param to the same values in all web.xml files within your EAR file:

   atg.session.parentContextName

   /portal

Note: This information applies only to session-scoped Nucleus components,

You must be set the same in ALL web.xml in the same ear file and the URL it points to must be a .war file with the SessionNameContextServlet defined in the web.xml.
In general if you leave “atg_bootstrap.war” in your big ear and do not change its context root from /dyn there is nothing to configure except making sure the nucleus servlet is defined in all web.xml files.