Experience Report Development of a Distributed CrossPlatform Simulator

Experience Report: Development of a Distributed Cross-Platform Simulator Thom Brooke Titan Corporation SIGAda 2002 December 10, 2002

Overview The System Satellite communications Terminal Control Simulator design Tools and environment Architecture Application Observations Some images © 2002 by Riverdeep, inc. , and its licensors. All rights reserved.

Satellite Communications Used For Wide Area Network No terrestrial assets Terminals Several types Access points

Network Topology TCP/IP backbone Point-to-Point links Conference nets Gateway

Terminal Functions Access point Functional Areas Antenna control Network control Resource monitoring

Terminal Control Laptop Planning tool Terminal Control RS-232 Interface Commands Terminal Automated Operator initiated TC

Terminal Protocols Communications RS-232 Serial PPP Alternating bit Message based Command Response(s) TC Terminal Setup Net 1 ACK Setup Complete Net 1 Active

The Problem Testing Training No Satellite Terminal(s) Terminal TC

Script-Based Tool Features Scripts Default responses Dynamic responses Good for Protocols Exceptional cases But No state information Messages Order dependent Wrong answer is “right”

Simulator: TSim Needs to model Satellite Local terminal TSim Remote terminal(s) System state Interface to TC IR&D project Proof of Concept Further than expected TC

Resulting Architecture TSim(s) partition Server TSim(s) Satellite “Virtual” terminals TSim(t) partition TSim(t) TC TC Client Terminal Multiple clients

Chronology Distributed GUI n Terminals 1 Terminal CLI

Development Tools GNAT The Ada 95 Booch Components Ada. Sockets TASH; Tcl/Tk RAPID GLADE (Distributed Systems Annex)

TSim Server Satellite UI Logon Antennas VT Satellite Virtual terminals Notification Payload Message Terminal

TSim Client Terminal UI Logon Notification Satellite Terminal EIF TC Interface Payload Message TC

Terminal Notification Monolithic Satellite Access type Distributed Terminal_Ptr Remote_Types Root_Payload Satellite Notify() VT Move Terminal Root_Terminal Revoke Terminal Virtual_Terminal

Message Interface EIF Satellite Terminal Part of Terminal Manages protocols Specialized links Root_Message EIF_Ptr Root_EIF Send() Assign Report Serial_EIF PPP_EIF

Cross-Platform Mix-and-Match (mostly) Simulator/TC, OS, and platform(s) TSim Linux TSim(s) TSim(t) Win 32

Configurations TSim Testing TSim(s) TSim(t) Training (Individual) TSim(t) Training (Group)

Observations Good support Tools Components Portability: just dumb luck? Distribution need not be difficult Nearly identical to non-distributed

Tool Support Ada. Sockets Platform availability Changes: 1 line (different version) TASH/RAPID Good combination RAD but not “industrial” strength

The Ada 95 Booch Components Many structures; many “forms” Better than rolling your own but the STL is still easier to use Allocation Layered instantiation Iterators