EUROCAE ED 262

Description / Abstract: PURPOSE AND SCOPE

INTRODUCTION

This document contains the technical Profiles of the Internet Engineering Task Force (IETF) Request for Comments (RFC) series of documents addressing relevant Application, Transport, Network, Addressing and Naming, Security, Mobility, and Multilink communication functions for the Internet Protocol Suite (IPS). These Profiles specify characteristics that should be useful to designers, installers, manufacturers, service providers and users for IPS systems intended for operational use within the United States National Airspace System (NAS) and the European Airspace. Where systems are global in nature, the system may have international applications which are taken into consideration.

Compliance with these Profiles will be mandated through the regulatory process to assure that the system and each subsystem will perform its intended function(s) satisfactorily under conditions normally encountered in routine aeronautical operations for the environments intended. The Profiles may be implemented by one or more regulatory documents and/or advisory documents (e.g., certifications, authorisations, approvals, commissioning, advisory circulars, notices, etc.) and may be implemented in part or in total. Any regulatory application of this document is the sole responsibility of appropriate governmental agencies.

Section 2.0 of this document describes the IPS and provides information needed to understand the rationale for system characteristics and requirements which are stated by IPS comprising the Transport, Network, Addressing and Naming, Security, Mobility, Multi-link, Network Management and System Interfaces. It describes typical application use cases and concept of operations, as envisioned by members of RTCA Special Committee - 223 and EUROCAE Working Group - 108 and establishes the basis for the Profiles stated in the following sections. Definitions and assumptions essential to proper understanding of this document are also provided in this section.

Section 3.0 of this document specifies the high-level functional requirements for each of the major IPS functions followed by references to Appendix A that identifies IPS profile tables by IPS Device Classes for each IETF RFC related to those functions. The IPS Device Classes are described in TABLE 1-2.

RTCA and EUROCAE acknowledge that all content reproduced from the RFCs are the intellectual property of IETF and have coordinated with IETF on their inclusion in this document. All IETF legends, legal notices and indications of authorship contained in the original IETF RFC are still in force. As per the request of the IEFT Trust, where more than one-fifth of such text is reproduced in RTCA/EUROCAE joint documents, all legends, legal notices and indications of authorship are reproduced in the RTCA/EUROCAE documents. For all RFCs discussed in appendix B, this information is included even if less than 1/5th of the RFC is included in this document.

Appendix D contains the complete list of RFCs mentioned in this document with hyperlinks to the IETF site to aide their use by the reader.

The word “subsystem” as used in this document includes all components that make up a major independent, necessary and essential functional part of the system so that the system can properly perform its intended function(s). If the system, including any subsystem, includes computer software, the guidelines contained in RTCA/DO-178() /EUROCAE ED-12() should be considered for airborne applications and other applicable standards for non-airborne applications.

HOW TO READ THIS DOCUMENT

The IPS System Overview and the IPS Operational Concepts described in Section 2.0 as well as the high-level functional requirements contained in Section 3.0 are intended to provide an adequate background to the reader of this document such that the profiles can be interpreted in the functional context of the IPS. Section 3.0 requirements are not normative for IPS. This Profiles Document is not intended to provide complete implementation guidance to the reader. In the future, for a comprehensive understanding of IPS operations and implementation, the reader must consult planned ICAO updates to existing documents.¹ for high-level requirements and operational guidance. Also of use is the planned creation of an IPS Minimum Aviation System Performance Standards (MASPS) by RTCA and EUROCAE. This MASPS will include detailed technical and performance requirements. The MASPS will also specify the verification methodology to be used by the regulatory agencies to certify an IPS implementation to support air traffic safety services. Additional IPS related standards, including and expected ARINC standard, are currently under development. These profiles are subject to revisions based on ongoing activities under ICAO, RTCA, EUROCAE and AEEC.

Appendix A of this Profiles Document contains normative IETF RFCs to support the IPS functional requirements specified in Section 3.0. These normative IETF RFC profiles were derived from the NIST and DoD IPv6 profiles and represent the minimum set of IETF RFCs that must be supported by each IPS Device Class, defined in TABLE 1-2. Optional IETF RFCs are not included in Appendix A because the RTCA standards only specify the minimum requirements for IPS. Vendors, OEMs and ANSPs may choose to implement other additional IETF RFCs, as long as they do not impact the interoperability, safety, security or performance of IPS.

In general, the functional RFCs in Appendix A are mandated in their entirety. However, the detailed IETF requirements for each RFC may not be applicable for all device classes in IPS. As such, Appendix B identifies detailed profiles for each of the IETF RFCs mandated in Appendix A where an exception is required for IPS. Appendix B is normative for IPS.

ESTABLISHMENT OF SC-223/WG-108 – TERMS OF REFERENCE

As Internet Protocol (IP) standards mature and current communication technologies are upgraded, or new systems are developed, a move to IP-based communication becomes a more viable and attractive alternative to existing technologies. Enterprises can begin to leverage the benefits stemming from a unified IP based communications strategy including greater network flexibility due to better scalability and ultimately better performance.

The Aviation Industry’s planned end-state has recently been identified as one based on Aeronautical Telecommunications Network – Internet Protocol Suite (ATN/IPS) standards. ICAO has planned to adopt the IPS standards for future aeronautical datalink communications to enable seamless, broadband, end-to-end communications.

FAA Management has directed that the existing ICAO Document 9896 ed.2 published in 2015 be updated to complete the Air/Ground (A/G) IPS requirements and to develop the corresponding A/G IPS Profiles and Minimum Aviation System Performance Specification (MASPS) documents in RTCA. All future FAA Aviation systems, including System Wide Information Management (SWIM) and Unmanned Aircraft System (UAS) Command Control (C2) Beyond Radio Line-of-sight (BRLOS) networks, can then be designed and developed leveraging these new communication standards to enable more effective and efficient sharing of data.

Following the schedule for the ATN/IPS deployment worked between US and Europe, EUROCAE also created WG-108 to provide a guidance document for ATN/IPS certification and deployment in Europe.

RTCA SC-223 and EUROCAE WG-108 decided to work together as approved by the PMC and the TAC on joint deliverables to ensure IPS consistency over US and EUROPE. The joint group will develop:

• IPS MASPS on IPS end-to-end interoperability and certification,

• IPS Profiles.

Based on the scope defined in the MASPS, the IPS profiles will leverage the IETF RFCs and their updates. However, aviation specific requirements will be addressed in the detailed profiles.

SCOPE OF INVESTIGATION

The current scope of IPS Profiles is the air/ground (A/G) communication supporting B1, B2, FANS, and AOC services. However, this does not preclude use of this minimum standard to support other services. UAS may use this minimum standard when they use services within its scope. UAS may also use this minimum standard when using networked RLOS and BRLOS services for applications specific to UAS such as command and control (C2). The desire is to maintain the IPS to be closely aligned with the commercial Internet Standards such that aviation industry can benefit from Commercial off the Shelf (COTS) implementations. The scope of this investigation has been limited to stable IETF RFCs in the Standards Track. However, IETF may update, add or make some of these RFCs obsolete in the future. Therefore, periodic update of this Profiles document is expected. In addition, as system implementations mature to gradually include more features -- resulting in increased performance -- more complex parts of the standard may be chosen by the aviation community to be incorporated into new and more-advanced IPS profiles. If so, some of the parameters provided in this document may have to be updated.

This document has investigated the use of Standards Track IETF RFCs against avionics needs.

It should be noted that the RFCs included in this document are minimum capabilities required to ensure Air/Ground interoperability and performance of aeronautical safety services. However, it is envisioned that these Profiles will equally satisfy the non-safety aviation services, thereby reducing overall implementation and operational costs of aviation networks.

GLOSSARY OF TERMS

Access network:

A network that is characterised by a specific access technology.

Administrative domain:

An administrative entity in the ATN/IPS. An administrative domain can be an individual State, a group of States, an aeronautical industry organisation (e.g. an air/ground service provider), or an air navigation service provider (ANSP) that manages ATN/IPS network resources and services. From a routing perspective, an administrative domain includes one or more autonomous systems.

ATN/IPS internetwork:

The ATN/IPS internetwork consists of IPS nodes and networks operating in a multinational environment.

ATN/IPS mobility management:

the collection of processes performed by aircraft and infrastructure that maintain continuous connectivity between aircraft and ground.

Autonomous system:

A connected group of one or more IP prefixes, run by one or more network operators, which has a single, clearly defined routing policy.

BRLOS:

Beyond radio line-of-sight refers to any configuration in which the transmitters and receivers are not in RLOS. BRLOS includes all satellite systems and any system where a controlling function, e.g. the Remote Pilot Station (RPS) of a Remotely Piloted Aircraft System, communicates with the Unmanned Aircraft via a terrestrial network which cannot complete transmissions in a timeframe comparable to that of an RLOS system.

Global mobility:

Global mobility is mobility across access networks.

Host:

A host is a node that is not a router. A host is a computer connected to the ATN/IPS that provides end users with services.

Host-based mobility management:

A mobility management (MM) scheme in which MM signalling is performed by the mobile node.

Inter-domain routing (exterior routing protocol):

Protocols for exchanging routing information between autonomous systems. In some cases, they may be used between routers within an autonomous system, but they primarily deal with exchanging information between autonomous systems.

Intra-domain routing (interior routing protocol):

Protocols for exchanging routing information between routers within an autonomous system.

IPS:

Internet Protocol Suite is the Aeronautical Telecommunication Network (ATN) based on commercial internet protocols to make aeronautical communications faster, safer, more secure, and more affordable.

IPS Air/Ground Router:

The IPS Air/Ground Router is a ground IPS router that interfaces directly with an adjacent airborne host/router over RF media. In other words, the air/ground router is the first-hop ground router for the airborne host/router.

IPS Boundary Router:

The IPS Boundary Router is a ground IPS router that routes IP packets across two interconnecting administrative domains.

IPS Host:

The IPS Host is the originator or terminator of IP packets in the IPS System. The IPS Hosts do not route IP packets that are not addressed to it.

IPS mobile node:

An IPS node that uses the services of one or more mobility service providers (MSPs).

IPS Router:

The IPS Router is the function that forwards Aviation Internet Protocol (IP) packets in transit from the originating Host to the destination Host through the IPS System. The IPS Router processes IP packets not explicitly addressed to them to perform routing and relaying functions.

IPS System:

The IPS System is the all-encompassing Aviation Internet that provides data transport, networking, routing, addressing, naming, mobility, multilink and information security functions to the aviation services. The IPS System includes the Layer 3 and Layer 4 functions of the ISO/IEC 7498-1 OSI 7-layer Reference Model. The IPS System does not include the underlying subnetwork functions that provide connectivity or the Applications.

Local mobility:

Local mobility is network layer mobility within an access network.

Location management:

The location management (LM) function is used to keep track of the movement of a mobile node and to locate the mobile node for data delivery.

Mobility service provider (MSP):

A service provider that provides IPv6 mobility service (e.g. mobility servers, home agents, etc.), within the ATN/IPS. An MSP is an instance of an administrative domain (AD) which may be an air/ground Access Service Network (ASN) provider, a Communication Service Network (CSN), an air navigation service provider (ANSP), an airline, an airport authority, a government organisation, etc.

Network-based mobility management:

A mobility management (MM) scheme in which the MM signalling is performed by the network entities on behalf of the mobile node.

Node:

A device that implements IPv6.

RLOS:

Radio line-of-sight refers to the situation in which the transmitter(s) and receiver(s) are within mutual radio link coverage and thus able to communicate directly or through a ground network provided that the remote transmitter has direct radio lineof- sight to the Remotely Piloted Aircraft (RPA) and transmissions are completed in a comparable timeframe.

Router:

A router is a node that forwards Internet protocol (IP) packets not explicitly addressed to itself. A router manages the relaying and routing of data while in transit from an originating end system to a destination end system.

IPS DEVICE CLASSES

SC-223/WG-108 realised that the IETF RFCs may not apply uniformly to all IPS subsystems. As such, IPS subsystems are categorised into five device classes, as shown in FIGURE 1-1, based on their intended roles within the aeronautical communication ecosystem. These device classes will be used to assign the profile requirements to one or more device classes when those requirements do not apply to the entire IPS system.

¹ Both ICAO Annex 10, Volume III and the ICAO Document 9896, Edition 3 are expected to be published in the near future.