RTCA SC-189/EUROCAE WG53: PUB-28 Annex G, Rev 0.7

AMCP WG-M WP -16

AERONAUTICAL MOBIL COMMUNICATIONS PANEL

MEETING OF WORKING GROUP M

Helsinki, Finland, 25 April – 3 May, 2001

Agenda Item 11:Review of the Results of the Subgroup of Nikolas Fistas

Information to Determine if VDL Mode 4 Must Develop Subnetwork Profiles for Interoperability

Presented by Brent Phillips

Prepared by Jane Hamelink

SUMMARY
This paper presents information developed in RTCA-189/EUROCAE-53 to specify VDL Mode 2 sub-network dependent requirements. It is provided to allow the group to assess if a comparable definition is needed for VDL Mode 4.

1Introduction

Because some of the ISO and 8208 standards allow for optional implementation of certain features it was found that for VDL Mode 2, more specific profiles were required to ensure air-ground interoperability. The information contained in the attached appendix was developed as part of RTCA SG-189 EUROCAE-53 work. The group was tasked with developing all the interoperability requirements needed for Baseline 1 air and ground systems.

2Proposal

This information in the attached appendix is presented for the groups’ consideration for determination if similar sub-network dependent profiles are required for VDL Mode 4.

Note: Information beyond what is strictly sub-network dependent was retained in the Appendix to this paper to provide the context for the sub-network information.

3Recommendation

It is recommended that if the group determines such profiles are required for VDL Mode 4, these profiles be included in the VDL Mode 4 Technical Manual to ensure global interoperability, rather than regional solutions as per RTCA/EUROCAE work.

Appendix

Communications Profile for an Airborne Combined End and Intermediate System

1.Introduction

1.1Scope

This document provides the communications profile for an Airborne Combined End System and Intermediate System (i.e., a system that combines an Airborne Router with a system hosting ATS applications such as CPDLC. An example of such a system is a CMU or ATSU).

Note.—This is not intended to rule out systems that also host AOC applications. However, a supplemental profile will be required to itemize the additional support needed for such applications.

1.2References

ISO/IEC TR 10000-1:1995. Information technology — Framework and taxonomy of International Standardized Profiles — Part 1: General principles and documentation framework.

ICAO Doc9705/AN956: 2nd Edition - Manual of Technical Provisions for the Aeronautical Telecommunication Network (ATN).

ARINC Characteristic 750, “VHF Data Radio”

ISO/IEC 8208:1995. Information technology — Data communications — X.25 Packet Layer Protocol for Data Terminal Equipment (Revision of ISO/IEC 8208:1990).

ISO/IEC 8473-1:1994. Information technology — Protocol for providing the connectionless-mode network service: Protocol specification.

ARINC Characteristic 758, “Communications Management Unit (CMU) Mark 2”

ARINC Specification 637-1, “Aeronautical Telecommunications Network (ATN) Implementation Provisions, Part 1, Protocols and Services”

ARINC Specification 631-3 “VHF Digital Link Implementation Provisions”, Published: October 16, 2000

2.System Context

The communications components of a system compatible with this profile are shown in Figure 21.

Figure 21 System Components

There are three major parts to this profile:

The Application Support Requirements are concerned with the Upper Layer protocols and the individual applications

The Subnetwork Independent Requirements are concerned with the Lower Layer protocols that are common to all types of subnetwork

The Subnetwork Dependent Requirements are concerned with the Lower Layer protocols and functions that are specific to each class of subnetwork.

3.Subnetwork Dependent Requirements: VDL Mode 2

3.1Static Requirements

The implementation shall provide an interface to the MAC Layer service provided by an ARINC 758 compliant VDR.

The implementation shall provide an Airborne AVLC implementation compliant with ARINC 631A.

The implementation shall provide an Airborne ISO 8208 implementation for the VDL Subnetwork compliant with ARINC 631A.

The implementation shall provide a Mobile SNDCF for use with the VDL Mode 2 subnetwork.

The Mobile SNDCF implementation shall support:

a)Local Reference Directory Maintenance (option McM/I).

b)Operation as the ISO 8208 Call Initiator (option clInit).

Note.—The options refer to the APRL entries in the ATN SARPs.

The Mobile SNDCF LREF Compression algorithm shall forward ECHO Request and ECHO Response PDUs as uncompressed PDUs (PDR 99100003).

The implementation shall support the ISO/IEC 9542 ES-IS protocol in compliance with the requirements specified in the ATN SARPs section 5.8.2.

3.2Dynamic Requirements

An implementation may use either the ISO/IEC 8208 non-standard default packet size facility or the ISO/IEC 8208 flow control negotiation facility in order to negotiate the optimal packet size (PDR 99100004).

The implementation shall support VDL Specific Addressing including the use of the ARS field.

The implementation shall support ICAO Administered and ICAO Delegated Ground Stations Addresses, and a System Mask comprising a sequence of binary ones followed by a sequence of binary zeroes (total 27 bits) without imposing a constraint upon the maximum number of binary ones other than the total length of the field.

Note.ARINC 631A only discusses ICAO Delegated Addressing and does not discuss ICAO Administered Addressing.

4.Subnetwork Independent Requirements

4.1Transport Layer Requirements

4.1.1Static Requirements

The implementation shall support the ISO 8073 Connection Mode Transport Protocol (TP4) in compliance with the requirements specified in the ATN SARPs section 5.5.

The implementation shall support and use the extended transport checksum parameter (PDR M0040002).

Note.—This requirement only applies to Build 1A and PETAL Operations only, but earlier implementations are encouraged to support it.

4.1.2Dynamic Requirements

Transport Layer timers shall be dynamically computed for each transport connection with configurable initial values.

ATN Transport Layer addresses shall be supported as specifed in section 5.4.2 of the ATN SARPs.

4.2Network Layer Requirements

4.2.1Static Requirements

CLNP

The implementation shall support the ISO/IEC 8473 Connectionless Network Protocol (CLNP) in compliance with the requirements specified in the ATN SARPs section 5.6.

The CLNP implementation shall support both End System and Intermediate System functions.

The CLNP implementation shall support the ATN Mobile SNDCF.

IDRP

The implementation shall support the ISO/IEC 10747 IDRP routing information exchange protocol in compliance with the requirements specified in the ATN SARPs section 5.8.3 for an Airborne Router supporting IDRP.

Support of jitter on IDRP timers shall be optional. (PDR 99070004).

4.2.2Dynamic Requirements

CLNP

ATN NSAP Addresses shall be supported as specified in section 5.4.3 of the ATN SARPs.

Outgoing CLNP PDUs shall be forwarded in compliance with the ATN SARPs section 5.3.2.

Outgoing CLNP PDUs of a higher priority shall be forwarded over an Air/Ground Datalink in preference to lower priority PDUs (ATN SARPs 5.2.8.4.1).

When congested, CLNP PDUs of a lower priority shall be discarded in preference to PDUs of a higher priority (ATN SARPs 5.2.8.4.2).

Route Initiation

The implementation shall support the Route Initiation procedures specified in section 5.3.5 of the ATN SARPs for an Airborne Router operating over Air Initiated Subnetworks.

The implementation shall support the encoding of ISH PDUs in call connect and call accept user data, and include ISH PDUs in call connect user data when ISO 8208 Fast Select is supported.

The implementation shall support both Join and Leave events provided by the VDL Mode 2 subnetwork.

The implementation shall support the Handoff event generated by the VDL Mode 2 Subnetwork.