Distributed Interactive Simulation
(DIS)

Program to electronically link organizations operating in four domains:

advanced concepts and requirements
military operations
research, development, and acquisition
training

Synthetic environment within which humans may interact through simulations at multiple sites networked using compliant architecture, protocols, standards, and data bases

Nickname for IEEE 1278.1 protocols

Modes of Simulation
Everything Is Simulation Except Combat

Live

operations with real equipment in the field
today, using instrumented ranges

Constructive

wargames, models, analytical tools
constructs a model C3I environment

Virtual

systems and troops in simulators fighting on synthetic battlefields
computer image generation for "out the window" view of virtual battlefield

Synthetic Theater of War - Europe
(STOW-E)

First major exercise to use live, constructive, virtual simulation together
US Army Europe, DMSO, ARPA

plus Army/Navy/AirForce/Marine labs, ranges

Core location: Grafenwoehr/Hohenfels GM
Stressed existing technologies to maximum

SAFOR
real/virtual/constructive interfaces
network scalability
network performance and security

Technologies Critical to DIS

Enabling technologies (off the shelf)

local area networking
microcomputers
computer graphics

Electronic Terrain

rapid terrain database generation
distributed dynamic terrain

Computer generated forces (CGF)

semi-autonomous forces (SAFOR)
automated commanders and C2 language

Wide area networking for large-scale DIS

wide area multicast
application gateways
exercise management

The DSI Network

C3I Advanced Simulation and Multimedia Network

Multicasting Architecture for DIS

What is multicasting?

One packet delivered to a group of addresses
Extension of original SIMNET broadcast

Why multicasting for DIS?

reduce WAN traffic for multi-site exercises, it grows ~n2(n square) unless network copies packets in transmission
reduce simulator input to manageable level (STOW traffic volumes too great for simulators)
these two purposes are at odds with each other

single MC group per exercise most efficient on WAN
many MC groups needed to reduce simulator input

DIS-CAS Proposed Reference Architecture for DIS Multicast Networking

What are the issues for multicasting?

WAN traffic (usually multiples of T1, or T3)

bought in quanta: after ~8 T1, a T3 is cost-effective

WAN protocol (ST2, IPmc, Frame Relay, ATM)
Encryption (link, NES, Fastlane)

link requires red-side routing, large tail circuits
NES not practical above ~5 Mbps (4 parallel NES)
Fastlane not available before `96 (multicasting `97?)
Fastlane will not support dynamic multicast groups

LAN traffic (LANs have inherent multicast)
LAN protocol (IPmc is clear winner here)

Dual-Mode Multicast in a Large Exercise

Dual-mode Multicast
How It Works

Dual-mode Multicast Architecture for DIS

Dual-Mode Multicast for DIS

Next steps:
Analysis of computational requirements (ongoing)
Prototype MC agent
Include new MC agent in engineering trials for STOW