AERONAUTICAL FIXED SERVICES GROUP (AFSG) of the European Air Navigation Planning Group (EANPG)

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1 AFSG/16 WP/16 04/04/2012 AERONAUTICAL FIXED SERVICES GROUP (AFSG) of the European Air Navigation Planning Group (EANPG) SIXTEENTH MEETING (Paris, April 2012) Agenda Item 4: AMHS Technical/Documentation Matters USE OF THE FILE TRANSFER BODY PART (FTBP) FOR CONVEYANCE OF FUTURE AERONAUTICAL DATA IN THE AMHS (Presented by the AFSG Planning Group) SUMMARY This Working Paper discusses the conveyance of emerging data types by means of the ATS Message Handling System (AMHS) making use of the File Transfer Body Part (FTBP) and provides a proposal for allocation and registration of Object Identifiers (OIDs) in order to indicate the different data types. 1. Introduction 1.1. Future ATM applications such as Digital NOTAM and Digital Flight Plan will increasingly deploy new data and information models. These emerging data and information models make use of the Extensible Markup Language (XML) for representation and exchange of information The XML is a general purpose language that defines a set of rules for representation and encoding of information. The fact that XML encoded information is human-readable and machine-readable at the same time is considered a significant advantage over other formats The ATS Message Handling Service (ATSMHS) already provides appropriate means for conveyance of such new data types. However, a refinement of the specification would improve support for emerging ATM applications and underline the suitability of the AMHS as a transport for future communications The proposed refinement addresses XML encoded data, but is also suitable for conveyance of other data types, e.g. such as commonly used in MET: binary data formats in meteorology like Gridded Binary 2 nd Edition (GRIB2) and the Binary Universal Form (BUFR) standardised by the WMO. (5 pages)

2 2 AFSG/16 WP/ At the 43 rd Meeting of the AFSG Planning Group in June 2011, a Working Paper was presented looking at the conveyance of XML encoded data using the ATSMHS. The Working Paper described several approaches for conveyance of future, textual data formats by the AMHS and outlined options for the identification of data types. After discussion the AFSG Planning Group decided to follow up on use of the File Transfer Body Part (FTBP) for conveyance of new data formats and to look at Object Identifiers (OIDs) for indication of data types At the 44 th Meeting of the AFSG Planning Group in September 2011 a follow-up Working Paper was presented providing technical details for conveyance of information using the FTBP in the AMHS. The Working Paper described the use of distinct application references in the FTBP parameters. After discussion the Meeting accepted the presented proposal which is based on the use of the sub-element registered-identifier of the element application-reference and the element user-visible-string of the parameter environment. The Meeting decided to allocate new OID values under the OID arc of ICAO and to evaluate the impact on existing documentation and systems At the 46 th Meeting of the AFSG Planning Group in March 2012 a final Working Paper was presented looking at the impact on documentation and existing systems resulting from the use of the File Transfer Body Part The present Working Paper summarises the latest discussion of the AFSG Planning Group. The AFSG Planning Group at its 46 th Meeting concluded to present the proposal to the AFSG/16 and to derive a Change Proposal for the EUR AMHS Manual which is intended to be processed and finalised within the next AFSG Planning Group session. 2. Discussion 2.1. This section discusses documentation, proposes a refinement, evaluates the impact on existing systems, and provides a proposal for allocation and registration of OID values. Documentation 2.2. Clause of ISO/IEC :2003 specifies the FTBP to convey contents and related information. The parameter environment of the file transfer parameters comprises the optional elements application-reference and user visible-string which are intended to identify application programs and versions ICAO Doc 9880 Part II (1 st Edition) introduces in section the use of the FTBP in the AMHS. The document does not include a profile (PRL) for the FTBP, but makes reference to section A of ISO/IEC ISP :2003 (AMH21) for definition of the file transfer parameters With Ref. 3.1 of AMH21 A.1.3.3, the ISP declares the element application-reference including its sub-element registered-identifier mandatory on origination and reception With Ref. 3.4 of AMH21 A1.3.3, the ISP declares the element user-visible-string mandatory on origination and reception Complementing ICAO Doc 9880, the EUR AMHS Manual (6 th Edition) specifies in Appendix B, section A the use of file transfer parameters For the sub-element registered-identifier; paragraph A b. specifies the abstract-value unknown-attachment but also allows for other OID values on multilateral agreement The EUR AMHS Manual puts no requirements on the element user-visible-string.

3 3 AFSG/16 WP/16 Proposed Refinement 2.9. In support of future ATM applications and related data formats it is proposed that parameters of the File Transfer Body Part (FTBP) conform to the following requirements The sub-element registered-identifier of the element application-reference should take one of the OID values associated with an application program (ATM application) included in the ATS application register. In case the ATS application register contains no suitable entry, the default OID value representing the abstract-value unknown-attachment shall be used The element user-visible-string of the parameter environment should be used to convey any additional, distinguishing information that might be of use to the receiver e.g. for presentation to a human user or in cases where the OID is not recognised by the receiving ATS Message User Agent. Systems As per AMH21 above, both elements under discussion are mandatory on generation and on reception, i.e. an ATS Message User Agent requires the capabilities to generate these elements on origination of messages and to interpret them on reception of messages. The generation of registered values for the subelement registered-identifier and the element user-visible-string remain optional The ATS Message User Agent of existing systems might not be able to generate an OID value distinct from unknown-attachment. This OID value remains valid ensuring backward compatibility. When not generated by the sending system, receiving systems in support of the proposed refinement would not benefit from the improvements Paragraph A b. of the EUR AMHS Manual allows for other OID values than unknown-attachment. Any existing system even though not supporting the proposed refinement requires the capability to accept other OID values on reception; however, it would not benefit from the improvements generated by the sending system. Allocation & Registration The ACP Working Group M in its 14 th Meeting discussed Working Paper 6 proposing an identifier registration based on ICAO Doc 9705 Sub-volume IX for inclusion in Part IV of ICAO Doc Following ICAO Doc 9705 and the draft presented to ACP WG-M/14, it is proposed to register for allocation of new OID values a sub-arc below the AMHS arc of ICAO {iso(1) identified-organisation(3) icao(27) atn-amhs(8)} referred to as icao-atn-amhs It is proposed to name this new a sub-arc application. Since the OID value 0 with name parameters is the only known registration below the arc icao-atn-amhs, the allocation of the new sub-arc application is expected to result in: {iso(1) identified-organisation(3) icao(27) atn-amhs(8) application(1)} Figure 1 below gives an overall view on the existing ICAO AMHS arc icao-atn-amhs, its context and the proposed allocation of the sub-arc application. The elements of the proposed sub-arc application are highlighted.

4 4 AFSG/16 WP/16 itu-t(0) iso(1) joint-iso-itu-t(2) icao(27) atn(0) atn-directory(7) atn-amhs(8) parameters(0) application(1) identifiedorganisation(3) amhs-precedencepolicy(0) Figure 1: ICAO arc including the proposed application sub arc Allocation of OID values below the ICAO AMHS arc icao-atn-amhs by the AFSG requires coordination with ICAO Montreal. Registration and publication of the related new OID values shall be established through a section or paragraphs in Appendix B of the EUR AMHS Manual (European ATS Messaging Service Profile). 3. Conclusion 3.1. The proposed refinement has no impact on the existing ICAO Doc With regard to the EUR AMHS Manual it is proposed to amend paragraph A b of Appendix B in order to reflect the use of registered OID values and to introduce paragraphs for registration and publication of OID values The proposed refinement is backward compatible to existing systems The allocation of new OID values in the sub-arc application to the ICAO AMHS arc icao-atn-amhs requires coordination with ICAO A draft Change Proposal (CP) to the EUR AMHS Manual, Appendix B is attached to this Working Paper in order to highlight the necessary extensions of the Manual regarding the use, allocation and registration of new OID values for the specification of file transfer parameters.

5 5 AFSG/16 WP/16 4. Action by the Meeting 4.1. The AFSG is invited to: a) note the content of this paper; b) provide comments to the presented material; c) discuss the impact on documentation and systems; d) discuss allocation and registration of OID values; e) support the presented solution; and f) invite ICAO Paris to co-ordinate the allocation of OID values with ICAO Montreal. END Attachment: Draft Change Proposal to the EUR AMHS Manual, Appendix B