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

Overview Mixed environment ATN protocol variants AMHS interoperability Impact and limitations

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

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

? 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

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

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

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)

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)

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)

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

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

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

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

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

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 

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

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

Thank you ! Hans-Joerg.Merkle@COMSOFT.aero