1. Presented by Thales Avionics ATN 2003 London, UK 23-24 September 2003
A Reusable Software Component  (RSC) Approach for the ATN Protocol Stack
Presented by Thales Avionics
ATN 2003
London, UK
23-24 September 2003

2. ACI’s Certifiable ATN RSC Baseline
ACI: Pioneer in ICAO SARPs-compliant ATN Router RSCs
ACI Partners: Honeywell, Thales ATM, Thales Avionics, Sofreavia
Operational deployments for FAA CPDLC Projects
CSC DLAP and Miami ARTCC Ground BIS Router delivered 2000
In operational service from 2002 for FAA Build I Program
Final release of basic ATN RSC delivered to ATNSI mid-2003
ACI ATN RSCs developed in close coordination with FAA
ACI coordinated design planning and development with FAA TRUST team (AIR-120) FAA guidelines for RSC methodology
FAA audits (SOI ) and DER follow-up assured that DO178B Level C RSC production objectives were met
ATN 2003 (London)

3. If the ATN RSC is “done”, why evolve the RRI ?
ATNSI/ACI RRI forms basis for an ATN RSC product line
RRI RSC specified (1996) for airborne/ground-based ATN OEM needs
Problem: VDL/2 specifications not complete at RRI specification freeze
Result: RRI RSC can be used for VDL/2, but efficiency-enhancing and DSP-specific VDL2 optimizations are missing
As software supplier to the avionics industry, Thales Avionics decided to develop a product line filling the VDL/2 gap…
Thales Avionics ATN VDL/2 RSC product derived from initial RRI RSC
First RRI-based avionics ATN VDL/2 router furnished in 2002
Followed-on with first avionics build for in FAA Build 1 in 2003
ATN 2003 (London)

4. Thales Avionics DO178B Level C ATN RSC
RRI RSC development
Coordinate Certification & SOI/Audit
CM, CPDLC, ADS RSCs
ASE RSC development
RRI RSC
Cert/Nav Authority
ACI & ATNSI
ACI
ATN VDL/2 RSC
VDL/2 RSC
Common Certification Artifacts
Cert/Nav Authority
ATN 2003 (London)

5. VDL/2 Features in Thales Avionics ATN VDL/2 RSC
Supports VDL Mode 2 Handoff
Acquisition and processing of ATN Handoff events in Internetworking and Subnetwork Dependent Convergence Function (SNDCF) layers
Maintains subnetwork compression context after VDL RGS Handoff
Maintains PLP (X.25) local references & connection information
Avoids renegotiating and rebuilding mobile compression data
Enhances transmission efficiency on the VDL2 link
Supports Call Redirection Facility
Ground PLP (X25) may redirect call to another router, allowing access to any VDL Mode 2 compliant sub-network
Support for both DSPs
ARINC: Ground RTR X.25 address references VPDN
SITA: Ground RTR X.25 address redirected using X.121 addressing facility
Supports balancing of traffic load & ensures inter-DSP compatibility
ISH PDU processing compliant with current ARINC 631 policy
ATN 2003 (London)

6. As an OEM, why use an RSC ?
Move from the traditional software development and certification approach (specific development for a specific target) TO
A reusable software approach, DO178B Level C AC20 RSC solution
Platform independent solution
Multi-platform target
Stand-alone certification artifacts and life cycle data
Certification credit usable after first approval, on subsequent implementations
Transfer DO178B Level C RSC certification artifacts & life cycle data to desired development environment & target platform
ATN 2003 (London)

7. Certification & Navigation Authority
The RSC Principle
OEM
DSP
Target 1
Target 2
Proto3
Host 1
Host 2
RSC System
Developer Integrator
Certification Certification Applicant Authority
RSC Certification
Certification & Navigation Authority
ACCEPTANCE
Reuse in subsequent programs, by other applicants and/or integrators
ATN 2003 (London)

8. From RSC to Integrator CERT/NAV Authority System Integrator Linkage
CERTIFICATION
CERT/NAV
Authority
SYSTEM DOC.
INTEGRATION 1 2 3
Level C
System Integrator Linkage
High level requirements to system requirements (ATN baseline requirements are ICAO SARPS and PICS)
RSC plans to System planning documents
Planning Documents
Porting Guides
HLR
SRS
High Level
testing
High Level
testing
SPEC
EICD
TEST 1
IN A, B OUT
Level D
Verification
traceability
& Coverage
SDD
RSC defines required porting in Porting Guide - System Integrator builds porting links around RSC
CODE
LL testing
System Integrator use RSC low level tests and functional tests – runs tests on OEM target
Code
RSC
DEVELOPMENT
Requirements Traceability
ATN 2003 (London)

9. Ease of Portation
STREAMS design levies minimal requirements on Hardware platform (minimum customization based on target OS)
Only two basic OS services need be made available thorough a specific customization module
Static Memory Management
Event Timers
Simple data exchange mechanism among stack modules and application modules
Also designed for partitioning between RRI and non-level C applications
Designed to facilitate certification
Plans, artifacts, tests & instructions ready for certification re-use
ATN 2003 (London)

10. How to get “airborne” with the Thales Avionics ATN RSC
The hosting environment exists today…
VDR (compliant A750 supporting VDL Mode 2 RF communication)
A communications unit ready to host the ATN VDL/2 RSC
Context Management and CPDLC applications with FAA/LINK message sets (ED110)
Many aircraft are now ready for installation of the DO178B Level C certification-ready ATN VDL/2 RSC
radio
ATC
Communications Unit
CM/ CPDLC
HMI
FMS
Flight Parameters
ATN
AIR-GROUND
DATALINK
ATN-VDL2
ATN 2003 (London)

11. Thales Avionics ATN VDL/2 RSC allows OEMs & users to enter
the Level C ATN world today !
CONTACTS
Forrest Colliver
Cedric D’Silva
ATN 2003 (London)