Messaging and Directory Server software used around the world in the Government, Military, Aviation and Commercial sectors.

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The AMHS Manifesto

This manifesto sets out the position of Isode and a number of other companies with regards to the AMHS market. If you want to sign up to this manifesto, please contact will.sheward@isode.com.

Basic ATS Message Service Compliance is not enough: The Case for using the EUR AMHS Target Profile today

Signatories This manifesto is supported by the following organisations: Artemis Communications Avitech Global Weather Dynamics Inc. Isode RDC Comunicaciones S.A. / Radiocom, Inc

The aviation industry is adopting AMHS to support ground-to-ground communications for services such as flight plans and meteorological data, to replace the current AFTN (Aeronautical Fixed Telecommunication Network) and CIDIN (Common ICAO Data Interchange Network). Yet most attention is focused on achieving Basic ATS Message Service compliance.

The Basic ATS Message Service is defined as part of AMHS. The EUR AMHS Target Profile is defined by Eurocontrol Agency, Directorate ATM Strategies (DAS), Communication & Surveillance Management Unit (CSM) and endorsed by the ICAO Aeronautical Fixed Services Group (AFSG) of the European Air Navigation Planning Group (EANPG). It is expected that the EUR AMHS Profile will become a part of the EUR AMHS Manual later in 2004.

This raises a key question. Given that services beyond Basic are achievable, why would an authority opt for an approach which covers only the requirements of the Basic ATS Message Service?

We believe that this focus on Basic is a direct result of an underplaying of the benefits and achievability of a higher level of AMHS service at this time by suppliers facing long development delays before Extended AMHS solutions from them are achievable.

The companies listed below are leading the drive to develop and implement systems that conform to the EUR AMHS Target Profile, believing that implementation of this broader Extended AMHS service makes more technical and financial sense for authorities than the gradual approach implied by the implementation of a system that confirms to Basic AMHS specifications.

The Basic approach will, we believe, inevitably be followed by a series of potentially disruptive, expensive but necessary additions as authorities strive to meet extended specifications.

The primary differences between the EUR AMHS Target Profile and the Basic ATS Message Service are:

Directory

Use of the Aeronautical Telecommunications Network (ATN) Directory, leads to a number of efficiency and security benefits including:

• Increased quality of service brought about by submission-time verification of recipient address and data reception capabilities. This ensures that messages are sent containing data that is in compliance with the abilities of the receiving party and that the number of 'bad' addresses entered into the system is sharply reduced.
• Smooth deployment by providing a mapping (lookup) between AFTN and O/R address structures, allowing the use of 8 digit AFTN addresses within the new environment whilst hiding the generation of O/R addresses from end users.
• The support of personal and shared address books (in a local directory), making the selection of recipients a clean, efficient and error-free process whilst allowing the storage of information on users not yet registered in the ATN-wide directory.

The use of an ATN Directory makes choosing recipients during message generation as simple as using a 'white pages' service to lookup addresses.

Sending Binary Attachments

Both the existing AFTN system and AMHS systems implemented in conformance with the Basic requirements are restricted to text messages. However, real requirements for binary messages are evolving a good example being the World Meteorological Organization's (WMO) decision to migrate to Binary Universal Form for the Representation of meteorological data (BUFR) for Coded Meteorological Messages.

Both support for ATN Directory and Binary Attachments are achievable today.

Systems Management

The EUR AMHS Target Profile defines use of Systems Management for AMHS, using XMIB. We believe that the systems management functionality is desirable and achievable today. However, it is not practical to use XMIB to achieve this , as CMIP implementations suitable to perform this management are not generally available. Use of Directory for configuration options, SNMP (Simple Network Management Protocol) for monitoring, and vendor specific functions for control is a better option.

We believe that the requirement to use XMIB should be reconsidered.

From the EUR AMHS Target Profile to the full Extended ATS Message Service: adding Security

There is one significant difference between the EUR AMHS Target Profile and the extended AMHS Message Service, defined by ICAO. This is the inclusion of security.

We believe that it is a pragmatic decision of the EUR AMHS Target Profile to not include security, as this makes it achievable today.

AMHS security policy aims at protecting ATS messages against the identified threats which are masquerade, modification and replay. The extended ATS Message Service achieves this security by use of digital signatures on messages and delivery reports..

Whilst the security requirements of Extended are not supported in solutions today, it is important that AMHS solutions are implemented with thought to the necessity of accepting the security requirements of Extended available in the near future.

Summary

Basic ATS Message Service is not enough, and AMHS deployments should be looking to deploy the EUR AMHS Target Profile, including support of directory and binary body parts. This should be done in a manner which will enable an easy transition to the full extended ATS Message Service.