High-level architecture (simulation)

A high-level architecture (HLA) is a general purpose architecture for distributed computer simulation systems. Using HLA, computer simulations can interact (that is, to communicate data, and to synchronize actions) to other computer simulations regardless of the computing platforms. The interaction between simulations is managed by a Run-Time Infrastructure (RTI).

Contents

Technical overview

A high-level architecture consists of the following components:

Common HLA terminology

Interface specification

The interface specification is object oriented. Many RTIs provide APIs in C++ and the Java programming languages.

The interface specification is divided into service groups:

Object model template

The object model template (OMT) provides a common framework for the communication between HLA simulations. OMT consists of the following documents:

HLA rules

The HLA rules describe the responsibilities of federations and the federates that join.[1]

  1. Federations shall have an HLA federation object model (FOM), documented in accordance with the HLA object model template (OMT).
  2. In a federation, all representation of objects in the FOM shall be in the federates, not in the run-time infrastructure (RTI).
  3. During a federation execution, all exchange of FOM data among federates shall occur via the RTI.
  4. During a federation execution, federates shall interact with the run-time infrastructure (RTI) in accordance with the HLA interface specification.
  5. During a federation execution, an attribute of an instance of an object shall be owned by only one federate at any given time.
  6. Federates shall have an HLA simulation object model (SOM), documented in accordance with the HLA object model template (OMT).
  7. Federates shall be able to update and/or reflect any attributes of objects in their SOM and send and/or receive SOM object interactions externally, as specified in their SOM.
  8. Federates shall be able to transfer and/or accept ownership of an attribute dynamically during a federation execution, as specified in their SOM.
  9. Federates shall be able to vary the conditions under which they provide updates of attributes of objects, as specified in their SOM.
  10. Federates shall be able to manage local time in a way that will allow them to coordinate data exchange with other members of a federation.

Base Object Model

The Base Object Model (BOM) is a new concept created by SISO to provide better reuse and composability for HLA simulations, and is highly relevant for HLA developers. More information can be found at Boms.info.

Federation development and execution process (FEDEP)

FEDEP, IEEE 1516.3-2003, is a standardized and recommended process for developing interoperable HLA based federations. FEDEP is an overall framework overlay that can be used together with many other, commonly used development methodologies.

Distributed Simulation Engineering and Execution Process (DSEEP)

In spring 2007 SISO started revising the FEDEP. It has been renamed to Distributed Simulation Engineering and Execution Process (DSEEP) and is now an active standard IEEE 1730–2010 (instead of IEEE 1516.3).

Standards

HLA is defined under IEEE Standard 1516:

Machine-readable parts of the standard, such as XML Schemas, C++, Java and WSDL APIs as well as FOM/SOM samples can be downloaded from the IEEE 1516 download area of the IEEE web site. The full standards texts are available at no extra cost to SISO members or can be purchased from the IEEE shop.

Previous version:

See also:

Prior to publication of IEEE 1516, the HLA standards development was sponsored by the US Defense Modeling and Simulation Office. The first complete version of the standard, published 1998, was known as HLA 1.3.

STANAG 4603

HLA (in both the current IEEE 1516 version and its ancestor "1.3" version) is the subject of the NATO standardization agreement (STANAG 4603) for modeling and simulation: Modeling And Simulation Architecture Standards For Technical Interoperability: High Level Architecture (HLA).

DLC API

SISO has developed a complementary HLA API specification known as the Dynamic Link Compatible (DLC) API. The DLC API addresses a limitation of the IEEE 1516 and 1.3 API specification, whereby federate recompilation was necessary for each different RTI implementation. Note that this API has since been superseeded by the HLA Evolved APIs, informally known as Evolved DLC APIs (EDLC).

HLA Evolved

The IEEE 1516 standard has been revised under the SISO HLA-Evolved Product Development Group and was approved 25-Mar-2010 by the IEEE Standards Activities Board. The revised IEEE 1516–2010 standard includes current DoD standard interpretations and the EDLC API, an extended version of the SISO DLC API. Other major improvements include:

Alternatives

While no direct alternatives to HLA are known to exist Distributed Interactive Simulation (DIS) is widely used for similar purposes. HLA was intended to succeed DIS as the interconnect fabric of choice for distributed Modeling and Simulation (M&S) exercises. However, interoperation among HLA participants requires the use of the same RTI vendor software and in some RTI implementations the same RTI version. This lack of a network (wire) level standard often forces applications to use the older DIS protocol.

See also

References

  1. ^ U.S. Defense Modeling and Simulation Office (2001). RTI 1.3-Next Generation Programmer's Guide Version 4. U.S. Department of Defense. 

External Links

Current
802 series
Proposed
Superseded
See also: IEEE Standards Association · Category:IEEE standards