Aggregate Level Simulation Protocol: Difference between revisions

Revision as of 20:29, 23 December 2010

Revision as of 19:30, 18 May 2011

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ALSP consists of:

#ALSP Infrastructure Software (AIS) that provides distributed runtime simulation support and management;

#A reusable ALSP Interface consisting of generic data exchange message protocols; and

#Participating simulations adapted for use with ALSP.

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==Contributions==

ALSP developed and demonstrated key aspects of distributed simulation, many of which were applied in the development of HLA.

* No central node so that simulations can join and depart from the confederation at will

* Geographic distribution where simulators can be distributed to different geographic locations yet exercise in the same simulated environment

* Object ownership so each simulation controls its own resources, fires its own weapons and determines appropriate damage to its systems when fired upon

* A message-based protocol for distributing information from one simulation to all other simulations.

* Time management so that the times for all simulations appear the same to users and so that event causality is maintained – events should occur in the same sequence in all simulations.

* Data management permits all simulations to share information in a commonly understood manner even though each had its own representation of data. This includes multiple simulations controlling attributes of the same object.

* An architecture that permits simulations to continue to use their existing architectures while participating in an ALSP confederation.

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DARPA sponsored the design of a general interface between large, existing, aggregate-level combat simulations. Aggregate-level combat simulations use [[Lanchester's laws|Lanchestrian]] models of combat rather than individual physical weapon models and are typically used for high-level training. Despite representational differences, several principles of SIMNET applied to aggregate-level simulations:

* ''Dynamic configurability.'' Simulations may join and depart an exercise without restriction.

* ''Geographic distribution.'' Simulations can reside in different geographic locations yet exercise over the same logical terrain.

* ''Autonomous entities.'' Each simulation controls its own resources, fires its own weapons and, when one of its objects is hit, conducts damage assessment locally.

* ''Communication by message passing.'' A simulation uses a message-passing protocol distribute information to all other simulations.

The ALSP challenge had requirements beyond those of SIMNET:

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==ALSP Infrastructure Software (AIS)==

The object-based conceptual framework adopted by ALSP defines classes of information that must be distributed. The ALSP Infrastructure Software (AIS) provides data distribution and process coordination. PrinciplePrincipal components of AIS are the ALSP Common Module (ACM) and the ALSP Broadcast Emulator (ABE).

===ALSP Common Module (ACM)===

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# A simulation sends an event-request message to its ACM with a time parameter corresponding to simulation time T, (the time of its next local event).

# If the ACM has messages for its simulation with timestamps older than or the same as T, the ACM sends the oldest one to the simulation. If all messages have timestamps newer than T, the ACM send a grant-advance to the simulation, giving it permission to process its local event at time T.

# The simulation sends any messages resulting from the event to its ACM.

# The simulation repeats from step (1).

The mechanism to support time-stepped simulation is:

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</pre>

The ownership and filtering information maintained by the ACM provide the information necessary to coordinate the transfer of attribute ownership between simulations.

===ALSP Broadcast Emulator (ABE)===

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===Inter-component Communications Model===

AIS employs a persistent connection communications model<ref name="boggs"> Boggs, D.R. Shoch, J.F., Taft, E.A., and Metcalfe, R.M. (1979). "PUP: An Internetwork Architecture," Report CSL-79- 10, XEROX Palo Alto Research Center, July.</ref> to provide the inter-component communications. The transport layer interface used to provide inter-component communications was dictated by simulation requirements and the transport layer interfaces on AIS-supporting operating systems: local VMS platforms used shared mailboxes; non-local VMS platforms used either Transparent DECnet or TCP/IP; and UNIX-like platforms use TCP/IP.

===ALSP Protocol===

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* ''Interaction.'' Interactions between objects are identified by kind. Interaction kinds are described by parameters, just as objects are described by attributes. When a simulation’s object engages either another simulation’s object or a geographic area, the simulation sends an interaction message to the ACM for further dissemination to other interested simulations.

* ''Refresh request.'' A simulation can request an update of a set of attribute values for any object or class of objects by sending a refresh request message to the confederation.

* ''Delete.'' When a simulation causes one of its objects to cease to exist, the simulation sends a delete message to inform other simulations.

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* Anita Adams, Gordon Miller, and David Seidel, November 1993, [http://ms.ie.org/alsp/biblio/93_annual_report/93_annual_report_pr.html "Aggregate Level Simulation Protocol (ALSP) 1993 Confederation Annual Report"], The MITRE Corporation. A history of the ALSP program in fiscal year 1993.

* William E. Babineau, Philip S. Barry, C. Zachary Furness, [http://ms.ie.org/alsp/biblio/SIW-Fall98/testing.rtf "Automated Testing within the Joint Training confederation (JTC)"], ''Proceedings of the Fall 1998 Simulation Interoperability Workshop'', Orlando, FL, September, 1998.

* MAJ John Bullington and Gordon Miller, September 1996, [http://ms.ie.org/alsp/biblio/MORS_TACSIM/mors_sep96.html "Intelligence Simulation Support to the Joint Training Confederation: Implications for Future Development"], TACSIM Project Office and The MITRE Corporation, published in the September 1996 edition of ''Phalanx, a MORS publication''.

* Lydia P. Dubon, 1993, [http://ieeexplore.ieee.org/iel4/5826/15525/00718362.pdf?arnumber=718362 "Joining a Distributed Simulation Environment via ALSP]," ''Proceedings of the 1993 Winter Simulation Conference''.

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* Laura Feinerman, Gordon Miller, David Prochnow, Richard Weatherly, Annette Wilson, and Anita Adams Zabek, [http://ms.ie.org/alsp/biblio/94_annual_report/94_an_rpt_pr.html "Aggregate Level Simulation Protocol (ALSP) Project 1994 Annual Report"], dated March 1995, The MITRE Corporation. A history of the ALSP program in fiscal year 1994.

* Mary C. Fischer, April 1994, [http://ms.ie.org/alsp/biblio/elecsim_94_paper_fischer/elecsim_connie.html "Aggregate Level Simulation Protocol (ALSP) - Managing Confederation Development"], U. S. Army Simulation, Training and Instrumentation Command. A paper presented on the ''1994 Elecsim Internet Conference''.

* Mary C. Fischer, Anita Adams, Gordon Miller, June 1994, [http://ms.ie.org/alsp/biblio/mors_94_fischer/mors_94_fischer.html "Aggregate Level Simulation Protocol (ALSP) - Training for the Future"], U. S. Army Simulation, Training and Instrumentation Command and The MITRE Corporation. A paper presented at the ''Military Operations Research Symposium 62'' meeting at the Air Force Academy in Colorado Springs, Colorado.

* Mary C. Fischer, December 1994, [http://ieeexplore.ieee.org/iel4/5825/15524/00717432.pdf "Aggregate Level Simulation Protocol (ALSP) - Managing Confederation Development"], U. S. Army Simulation, Training and Instrumentation Command. A paper presented at the ''1994 Winter Simulation Conference'' in Orlando, Florida.

* Mary C. Fischer, April 1995, [http://ms.ie.org/alsp/biblio/itec_95_fischer/itec_95_fischer.html "Aggregate Level Simulation Protocol (ALSP) - Future Training with Distributed Interactive Simulations"], U. S. Army Simulation, Training and Instrumentation Command. A paper presented at the ''1995 International Training Equipment Conference'' on 25–27 April 1995 at The Hague in The Netherlands.

* Mary C. Fischer, September 1995, [http://ms.ie.org/alsp/biblio/DRG_Paper/36nato-w.html "Joint Simulated Battlefield"], U. S. Army Simulation, Training, and Instrumentation Command, published in ''Proceedings of the 36th Defence Research Group (DRG) Seminar on Modeling and Simulation'', 5–8 September 1995, Washington, D.C.

* Mary C. Fischer, October 1995, [http://ms.ie.org/alsp/biblio/SESC_Paper/sesc95w.html "Joint Simulated Battlefield Through Aggregate Level Simulation Protocol'], U. S. Army Simulation, Training, and Instrumentation Command, published in ''Proceedings of the Southeastern Simulation Conference '95'', Orlando, FL.

* Mary C. Fischer, March 1996, [http://ms.ie.org/alsp/biblio/SIMTECT_Paper/simtect3.html "Joint Training Confederation"], U. S. Army Simulation, Training, and Instrumentation Command, published in ''Proceedings of the First International Simulation Technology and Training (SimTecT) Conference'', 25–26 March 1996, Melbourne, Australia.

* Sean P. Griffin, Ernest H. Page, Zachary Furness, Mary C. Fischer, [http://ms.ie.org/alsp/biblio/SIMTECT97/PAPER.html "Providing Uninterrupted Training to the Joint Training Confederation (JTC) During Transition to the High Level Architecture (HLA)"],''Proceedings of the 1997 Simulation Technology and Training (SimTecT) Conference'', Canberra, Australia, 17–20 March 1997.

* George J. McFadden, [http://ms.ie.org/alsp/biblio/SIW_Spring00/00S-SIW-032.doc "An Approach to Management of Enumerated Data in Federations"], ''Proceedings of the Spring 2000 Simulation Interoperability Workshop'', Orlando, FL, March, 2000.

* Gordon Miller and Anita Zabek, March 1996, [http://ms.ie.org/alsp/biblio/mors_96_miller/mors_96.html "The Joint Training Confederation and the Aggregate Level Simulation Protocol"], The MITRE Corporation, published in the June 1996 edition of ''Phalanx, a MORS publication''.

* Ernest Page, Brad Canova, John Tufarolo, February 1996 (revised September 1996), [http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.37.1829&rep=rep1&type=pdf "A Case Study of Verification, Validation and Accreditation for Advanced Distributed Simulation"], ''ACM Transactions on Modeling and Computer Simulation'', July 1997.

* David L. Prochnow, Ernest H. Page, Mary C. Fischer, [http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.37.935&rep=rep1&type=pdf "Management of the Joint Training Confederation Family of Specifications"], ''Proceedings of the Spring 1997 Simulation Interoperability Workshop'', Orlando, FL, 3–7 March 1997.

* David L. Prochnow, Mary C. Fischer, [http://www.sisostds.org/index.php?tg=fileman&idx=get&id=2&gr=Y&path=Simulation+Interoperability+Workshops%2F1997+Spring+SIW%2F1997+Spring+SIW+-+Papers+and+Presentations&file=007.mcw "Unique Requirements for the Representation of Logistics in a Distributed Simulation Environment for Military Training"], ''Proceedings of the Spring 1997 Simulation Interoperability Workshop'', Orlando, FL, 3–7 March 1997.

* David L. Prochnow, Ernest H. Page, Bryan Youmans, [http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.37.6101&rep=rep1&type=pdf "Development of a Federation Management Tool: Implications for HLA"], ''Proceedings of the Spring 1998 Simulation Interoperability Workshop'', Orlando, FL, 9–13 March 1998.

* David Seidel, March 1993, [http://ms.ie.org/alsp/biblio/89-92_history/89-92_history.html "Aggregate Level Simulation Protocol (ALSP) Program Status and History"], The MITRE Corporation. A history of the ALSP program from its beginning in 1989 through 1992.

* John Tufarolo and Ernest Page, [http://portal.acm.org/ft_gateway.cfm?id=256869&type=pdf&coll=portal&dl=ACM&CFID=3273248&CFTOKEN=54531066 "Evolving the VV&A Process for the ALSP Joint Training Confederation"], ''Proceedings for the 1996 Winter Simulation Conference'', pp.&nbsp;952–958, Coronado, CA, 8–11 December 1996.

* Richard Weatherly, David Seidel, and Jon Weissman, July 1991, [http://ms.ie.org/alsp/biblio/ssc_91_paper/SSC_91_Paper.html "Aggregate Level Simulation Protocol"], The MITRE Corporation. A paper presented at the ''1991 Summer Computer Simulation Conference'' in Baltimore, Maryland

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* R.M. Weatherly, A.L. Wilson, B.S. Canova, E.H. Page, A.A. Zabek, M.C. Fischer, January 1996, [http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.37.4784&rep=rep1&type=pdf "Advanced Distributed Simulation Through the Aggregate Level Simulation Protocol"], published in ''Proceedings of the 29th Hawaii International Conference on System Sciences'', Volume 1, pp.&nbsp;407–415, Wailea, Hawaii, 3–6 January.

* Annette Wilson and Richard Weatherly, April 1994, [http://ms.ie.org/alsp/biblio/elecsim_94_paper/Elecsim_94_mod.html "New Traffic Reduction and Management Tools for ALSP Confederations"], The MITRE Corporation. A paper presented on the ''1994 Elecsim Internet Conference''.

* Annette Wilson and Richard Weatherly, December 1994, [http://ieeexplore.ieee.org/iel4/5825/15524/00717433.pdf?tp=&isnumber=&arnumber=717433 "The Aggregate Level Simulation Protocol: An Evolving System"], The MITRE Corporation. A paper presented at the ''1994 Winter Simulation Conference'' in Orlando, Florida.