1. AMHS Interoperability
AMHS Implementation Workshop
Chennai, India
15–16 December 2008

2. Overview Mixed environment ATN protocol variants AMHS interoperability
Impact and limitations

3. Mixed Environment AMHS Transition period AFTN AMHS ATN/OSI ATN/IPS+
AMHS
ATN/ISP
ATN/OSI
AMHS
AFTN + AMHS
AFTN
AMHS

4. End User Connectivity AFTN AFTN AMHS AFTN AMHS AMHS AFTN to AFTN
AFTN to AMHS and vice versa
AMHS to AMHS
AFTN
AFTN
AFTN
AFTN
AMHS
AFTN
AFTN
AMHS
AMHS
AMHS
AMHS
AMHS

5. ? ATN Protocol Variants AMHS over ATN/OSI AMHS over ATN/IPS
Initial approach as per ICAO Doc 9705
Adopted early by ASIA/PAC Regions
AMHS over ATN/IPS
Introduced to use widespread IP technology
Optional in ASIA/PAC Regions
AMHS
over
ATN/IPS ?
AMHS
over
ATN/OSI

6. AMHS Protocol Stack AMHS Application AMHS upper layers
based on OSI 7 layers
AMHS upper layers
Layers 5 - 7
Uniform
Independent of networks
AMHS lower layers
Layers 1 - 4
ATN/OSI or ATN/IPS

7. AMHS over ATN/OSI Transport Protocol Class 4
Connectionless Network Protocol
Various sub-networks
LAN: LLC1, ...
WAN: X.25, ...
ATN Router
Unique to aviation due to extensions
Designed to support G/G and A/G
Open for integration of other sub-networks

8. AMHS over ATN/OSI Example for a pure ATN/OSI environment
AMHS Applications operate over LAN (e.g. TP4 / CLNP / LLC1)
ATN Router interconnect using WAN (e.g. CLNP over X.25)

9. AMHS over ATN/IPS Transport Protocol Class 0
Transmission Control Protocol
Internet Protocol
IPv4 (RFC 1006)
IPv6 (RFC 2126)
Standard IP Router
Interoperability IPv4/v6 by Network Address Translation and Protocol Translation (NAT/PT)

10. AMHS over ATN/IPS Example for a pure ATN/IPS environment
AMHS Applications operate over LAN (e.g. TCP/IP / Ethernet)
IP Router interconnect using WAN (e.g. TCP/IP over Frame Relay)

11. Coexistance of ATN/OSI and ATN/IPS
How to connect ?
Common Protocol Stack required
Protocol stacks are not compatible!

12. AMHS using Dual Stack Router
Example for a dual stack router
AMHS End Systems operate over LAN
ATN Router implements both stacks and a Transport Bridge

13. AMHS using Dual Stack Application
Example for a dual stack ATS Message Server
AMHS Application implements both stacks
ATN Router interconnects using ATN/OSI
IP Router interconnects using ATN/IPS

14. AFTN/AMHS Gateway Interconnects AMHS with AFTN
Seamless transition from AFTN to AMHS
AFTN – AFTN over AMHS
Bi-directional message exchange
ATS Messages
Conversion of addresses and contents
Limitations from AMHS to AFTN
Transparent to end users
End users can migrate any time

15. AFTN/AMHS Gateway AFTN – AMHS AFTN – AFTN AMHS
AFTN/AMHS Gateway on AFTN side
AFTN – AFTN
AFTN/AMHS Gateway on both sides
AMHS
ATS Message
Server
AFTN/AMHS
Gateway
AFTN
AFTN/AMHS
Gateway
AFTN
AMHS

16. Interoperability Tests
Ensure interoperability of products from different suppliers
ASIA/PAC AMHS Manual
Conformance (Annex B)
Interoperability (Annex E)
Per-Operational (Annex F)
ATN Routers and AMHS Applications are interoperable
Trials
Interoperability tests
Daily operation 

17. Plans for ASIA/PAC Regions
Strategy for ATN/IPS in ASIA/PAC is under consideration
Backbone systems implement dual stack solutions
ATN/OSI
ATN/IPS
Non-backbone system may implement ATN/OSI or ATN/IPS
Long-term objective: ATN/IPS

18. Summary Coexistance of ATN/OSI and ATN/IPS Integration of AFTN users
Dual stack routers or applications
Integration of AFTN users
AFTN/AMHS Gateway
Transparency for end users
AFTN
AMHS
Interoperability Tests
ASIA/PAC: AMHS Manual
EUR: ECG initiative and AMHS Manual

19. Thank you !