The Global Deployment Descriptor File
Integration Server uses the global deployment descriptor file in Integration Server_directory \instances\instance_name\web\conf\web.xml to specify default configuration settings for all web applications you deploy on Integration Server. These settings include:

Definitions for the built-in servlets that serve all web applications, include servlets that handle requests for static resources, compile and execute JSPs, and process Server Side Include (SSI) directives and Common Gateway Include (CGI) scripts

Default mappings for the servlets, JSP file name extensions, and MIME (content-type) properties

Session timeout value

Names of welcome files

Security constraints
You can customize the global deployment descriptor file as needed. The changes you make to this file apply to all web applications on the current Integration Server instance.
You can also augment or override the defaults in the global deployment descriptor file for selected web applications. To do so, you update the deployment descriptor file for each application and include the appropriate security sections for the application. Integration Server processes the global deployment descriptor file first and then processes the application’s deployment descriptor file.