Web Services Supporting Simulation to Global Information Grid

1. Web Services SupportingSimulation to Global Information Grid Mark Pullen George Mason University with support from partners Don Brutzman, NPS Andreas Tolk, ODU Katherine Morse, SAIC

2. Extensible Modeling & Simulation Reporthttp://www.movesinstitute.org/xmsf • Web-based technologies applied within an extensible framework will enable a new generation of modeling & simulation (M&S) applications to emerge, develop and interoperate. • Support for operational tactical systems is a missing but essential requirement for such M&S applications frameworks. • The framework of Extensible Markup Language (XML)-based languages can provide a bridge between forthcoming M&S requirements and open/commercial web standards, while continuing to support existing M&S technologies. • Compatible and complementary technical approaches are now possible for model definition, simulation execution, network-based education, network scalability, and 2D/3D graphics views. • The Web approach for technology, software tools, content production and broad use provides best business cases from an enterprise-wide (i.e. world wide) perspective.

3. Web Services • Definition: a self-contained, self-describing unit of modularity for publishing and delivering XML-based digital services over the Internet. • natural extension of the concept of a resource • sits on the network and does something we need • accepts messages and returns replies • encoded in XML • peer-to-peer or client-server

4. Specifying Web Services • Externally visible behavior is described in terms of the syntax, semantics, and sequencing of messages exchanged between the service provider and its client • Described using an XML Schema vocabulary • Web Service interface description document specifies a contract between the service provider and its client.

5. Web Services Model Service Provider Service Consumer Service Registry

6. XML • Universal meta-language of the Web • Used for data, content, messaging, and computing to provide point-to-point integration in a platform-neutral way • Document structure, content and semantics defined by XML schema • Basis for a new generation of lightweight application-level protocols now emerging

7. Simple Object Access Protocol(SOAP) • XML-based, lightweight messaging protocol for exchange of typed information in decentralized, distributed environments • Enables interoperability among (existing) distributed applications running on disparate, heterogeneous platforms using a modest infrastructure • Guiding principles are simplicity and extensibility by modularity. • Does not define a programming model or require a specific network transport. • Simply consists of a modular packaging mechanism and a set of encoding rules.

8. Implementing Web Services • Develop an ontology for data management • use it to define an XML tagset • Define the services to be provided • any function is a candidate • an example: digital terrain • Provide software for each service • new development: generally in Java • legacy code easily wrapped to appear as a service • Package the XML in SOAP for transmission • Interoperate! • examples: XDV via Web-Enabled RTI; XBML

9. Critical Points • XML is a mature technical standard for information exchange • and getting even better: compressed/binary form soon • but it is useless without data management namespace • SOAP is an effective means to transport XML-encoded data across networks • but it is only a component of a larger system • There is no magic here, just better technology • software is still complex and expensive! • but interoperation is simpler to achieve • and technology development paid for commercially

10. How Does This Relate to the GIG? • XML/SOAP are great for data distribution • support the Common Operating Picture • But to get to the next level up, we still need to deal with meta-information • behavioral representation composability, as in XBML • The simulation community has begun work on Web Service Profiles to support this • The same technologies empower the GIG • we need to manage the namespaces and meta-information so they work together • then M&S becomes a powerful C4I system capability

11. M&S Service One View of the Future Communities of Interest Etc. GIG Enterprise Services M&S Service Comms Backbone ESM Messaging Mediation Security User Asst Net Centric Enterprise Services Discovery Collaboration Storage App M&S Service Notional only - does not imply one “box” per service etc. Edge Users

12. References • Two key papers are available today as handouts • A collection of publications is at: http://netlab.gmu.edu/xmsf/pubs