AMHS ATS Message Handling System

1
AMHS(ATS Message Handling System)
Presentation ATN2.4-Part B

• Presented by
• Hoang Tran
• U.S. FAA/AOS-900

2
AMHS Definition

• Provides a ATN-specific messaging system
• Similar to AFTN and can interoperate with it
• Based on ITU-T X.400 standards
• Three main classes of service
• ATS Basic Service (Doc. 9705 Ed. 2)
• ATS Extended Service (Doc. 9705 Ed. 3)
• AFTN/AMHS Gateway (Doc. 9705 Ed. 2)

3
AMHS in the ATN

• AMHS first ground-ground ATN application defined
• Doc. 9705 Sub-Volume 3 contains definition

4
AMHS Requirements

• Provide a messaging service over the ATN
• Deliver a level of service at least equivalent to
  the that of the AFTN
• Allow transition from AFTN to ATN
• AMHS users to/from AMHS users
• AMHS users to/from AFTN users
• AFTN users to/from AFTN users via ATN

5
AMHS Basic Service

• Original AMHS Specification
• Adapted to Aeronautical Environment, especially
  AFTN Functionality
• Defines very limited format (AFTN-like)
• Restricts X.400 capabilities to limited subset
  (messages consist of single IA5 body-part)
• Maps AFTN service elements to fields in message
  text

6
AMHS Extended Service

• Most recently defined enhancements to AMHS (Doc.
  9705 Ed. 3)
• Extends the number and types of body-parts (i.e.,
  message contents)
• Specifies a mapping of message elements to
  standard X.400 fields
• Adds user authentication (security)
• Adds use of ATN Directory Service
• Defines system management requirements
• Defines a CIDIN Gateway

7
AFTN/AMHS Gateway

• Allows Transition from AFTN to ATN
• Defines interoperability between AFTN systems and
  AMHS
• Defines mappings between AFTN services and AMHS
  services

8
AMHS Components

• Message Transfer Agents (MTAs)
• Provides the message transfer and delivery
  functions
• User Agents (UAs)
• Provides end-user message sending and reading
• Mostly defined by implementation rather than
  SARPs
• Control Position
• ATN specific management station
• AFTN/AMHS Gateway
• Provides interoperability between AFTN users and
  AMHS users

9
AMHS MTA

• Implements X.400 messaging functions
• Message submission
• Message forwarding
• Message Delivery

10
ATN AMHS MTA

• ATN AMHS MTA specific functions
• Limited body part types
• 1 IA5 (text) message part
• Limited message formats
• Defines an AFTN-like message format
• Logging of messages
• Satisfies long-term retention requirements of
  ICAO Annex 10

11
AFTN/AMHS Gateway

• Defines a Message Transfer and Control Unit
  (MTCU)
• Maps between AFTN messages and AMHS messages
• Processes AFTN service messages
• Maps between AFTN and AMHS priorities
• Defines Control Position functions
• Display of errors
• Interface for correction of errors in AFTN
  messages
• Defines an AFTN component
• Behaves like an AFTN center
• Responds to AFTN service messages that do not
  generate AMHS message

12
AFTN User-to-AFTN User
A
IS
D
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FAA ATN AMHS

• by
• Hoang Tran
• US FAA/AOS 900

14
ATN Program Overview

• FAA has developed the following ATN Products
• AMHS with integrated AFTN/AMHS gateway
• AMHS User Agents

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AMHS Product Descriptions

• AMHS
• Implements ICAO Doc. 9705 ed. 2
• MTA based on Asia/Pac AMHS ICD
• AFTN/AMHS Gateway based on Asia/Pac ICD
• Proprietary UA
• Proprietary Control Position
• X.25 interfaces to AFTN
• LAN interfaces to ATN router

16
AMHS Product Description (2)

• AMHS UA
• based on JAVA technology
• access to remote Message Transfer Agent (MTA)
• allows for both AFTN over X.400 and X.400 message
  generation
• provided with customization if required

17
AMHS Product Architecture

• Hardware
• MTA
• either single workstation or dual/redundant
  workstation with automatic switch-over
• NetBSD
• Control Position/X.25 interface
• PC (Windows)
• UAs
• any network capable computer

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AMHS Product Architecture (2)

• Software
• all software written in C except UA
• file based for reliability

19
AMHS Product Architecture (3)
FAA
Control Position
X.25
AFTN
MTA
Window
X.25
LAN
TCP/IP/
CLNP
ATN
R
UA
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MTA and Control Position

• Flow control
• implements priority mechanisms for processing
  messages
• all processing is file based
• Loss of X.25
• files stored at control position until error
  cleared
• MTA message processing continues during X.25
  errors

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MTA and Control Position (2)

• X.25 Status Monitoring
• card monitor
• circuit monitor
• Probes and Non-Delivery Reports (NDR)
• NDRs generated and received by MTA
• sent to control position
• database of AFTN and AMHS messages for NDR
  correlation
• Probes supported

22
MTA and Control Position

• Scripts for log file maintenance
• run in background
• creation of CD-ROM of log files
• Statistics
• basic gathering of statistics and log information
• database recording of statistics

23
MTA and Control Position

• MTA has no HMI - all through the control position
• Control Position - window based
• editing of messages with errors
• control of the MTA

24
User Agent (UA)

• JAVA-based HMI
• Both AFTN over X.400 and X.400 message creation
  screens
• Storage of all received/read messages
• Sorted by selected fields
• Address management with lists and address book
• Generation of probes

25
Demonstration System
UA
MTA1
MTA2
AFTN Terminal
Control Position
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THANK YOU

• Any Questions?