ACP-SWGN1-11/WP-1118
International Civil Aviation Organization
10 Nov 2006
WORKING PAPER
AERONAUTICAL COMMUNICATIONS PANEL (ACP)
11th MEETING OF SUB-WORKING GROUP N-1
Montreal, Canada 13-17 November 2006
Agenda Item 5.5:
Review of latest modifications to the SARPs (Annex 10, Chapter 3)
Comments about proposed SARPs amendments
(Prepared by Jean-Marc Vacher – SWGN3 Chairman)
SUMMARY
This working paper provides detailed comments about the proposed
modifications of ATN SARPs contained in Annex 10, Volume III, Chapter 3
ACTION
SWGN1 is requested to review the attached comments and to update the
proposed SARPs Amendment accordingly.
Note Secretary: References to WP’s 1105, 1106 and 1107 changed into WP’s 1113, 1114 and 1115
respectively
1.
INTRODUCTION
1.1
This working paper provides one general comment and detailed comments by the
SWGN3 Chairman about the proposed modifications of Annex 10, Volume III, Chapter 3, discussed in
SWGN1-10 and complemented with further proposals to be discussed in SWGN1-11. The comments in
the present paper are based on the contents of SWGN1-11 WP1113 and WP 1114.
2.
DISCUSSION
2.1
General comment
2.1.1
Overall, the amendments to the SARPs tend to modify the paradigm adopted for the
ATN, which currently includes an inter-network, upper layer communication services and ATN
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applications. It is now unclear whether the applications are considered as part of the ATN (the former
paradigm) or whether the ATN is "in support of" applications (used by applications) defined elsewhere, in
a non-ATN document, typically in Doc 9694. However, Doc 9694 does not express technical
requirements, but only operational requirements. One of the outcomes of the process is that each
"application clause" (3.5.1.1.1, 3.5.2.1.1, 3.5.2.2.1 etc.) which previously included a Note referring to
Document 9705 now contains a reference to Document 9694. But the references to Doc 9705 would still
be useful.
2.1.2
Some comments in WP 1115 (e.g. comment under 3.4.28) also tend to convey this idea:
"Is the ICS not in reality the ATN ?". The ICS is the ATN inter-network and transport. But the ATN
includes ICS, ULCS and applications.
2.1.3
It should be made clear in the SARPs that the ground-ground and air-ground applications
are part of the ATN.
2.2
Ref
The detailed comments are contained in the following table.
Commented
Paper
1
Section
Comment
Definitions
The definition of AIDC has been shortened, conversely to what had been agreed
in WGN06 and SWGN1-10. It is now mismatching the AIDC concept as
defined by OPLINKP: the provided definition could include exchange of any
kind of data, e.g. surveillance data although it has now been specifically
excluded of AIDC.
WP1113
2
Definitions
WP1113
3
3.2.2
WP1113
4
3.4.3
WP1114
The definition present in WP 1114 (and agreed at WGN06) should be used:
"... between Air Traffic Services Units in support of flight notification, flight
coordination, transfer of control and transfer of communication."
The deletion of the definition for AMHS – ATS Message Handling System has
not been agreed (see WP1106 for reference).
The two notions of ATSMHS and AMHS are different and the two definitions
should be maintained.
This is one of the places where the general comment in section 2.1 above
applies. The first sentence in the former section 3.2.2 "The ATN and the
associated application processes have been designed in support of the
communications, navigation, surveillance and air traffic management
(CNS/ATM) systems" (see WP1114) should not be deleted. Or, an alternative
proposal could be:
"the ATN inter-network, upper layer communication services and applications
are specifically and exclusively intended to provide data communications
services etc."
The comment in the 2nd box under 3.4.3 in WP1114 reflects a misunderstanding
about the status of CIDIN: CIDIN is not being phased out in Europe. There are
two applications in CIDIN, the AFTN application and the OPMET application.
Only the OPMET application is being phased out. The AFTN application is
used extensively, and it will indeed transition into the ATN environment using
AMHS.
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Ref
Commented
Paper
5
Section
Comment
3.4.3
Because of the phasing out of the CIDIN/OPMET application (see above), the
CIDIN/AMHS gateway is no longer a requirement, as stated in the WGN06
meeting. Transition of users of the CIDIN/AFTN application into the ATN
architecture is feasible using only the AFTN/AMHS gateway. Thus the
following small amendment is proposed:
"The AFTN/AMHS gateway shall ensure the interoperability of AFTN and or
CIDIN stations and or networks with the ATN."
An ATN application may operate over the IPS through a convergence (rather
than conversion) function. This is not exclusive from using also ULCS. For
example when RFC1006 or RFC2126 is used, it is in reality the upper layers
(embedded with the ATN application) which use the convergence function.
Thus the following change is proposed in the 2nd and 3rd sentences, to make the
text less restrictive:
"ATN applications may operate over the Internet Protocol Suite as a direct
application or through a convergence conversion function. ATN applications
may also alternatively make use of the OSI ULCS."
With the deletion of the former section 3.6.1, there is no longer any clause in the
SARPs regarding the ATN OSI Upper Layer Communications Service
(contained in Doc 9705 Sub-Volume IV). This contradicts the reality of current
air-ground applications and the contents of the Note under 3.6. It is also a gap in
the overall architecture in case the OSI stack is used.
WP1113
6
3.6 Note
WP1113
7
WP1113
ACP-SWGN1-11/WP-xx
3.6 (whole
section)
WP1114 refers to the deletion as "agreed in WGN06". This appears to be a
technical mistake by WGN06.
[Note by WP author: Is there not some kind of confusion here ? WP1114 says
that the paragraph was inadvertently inserted in the proposals for SWGN1-10,
but maintaining it was actually more logical than deleting it.]
The former sections 3.6.1 and 3.6.1.1 should be re-inserted and renamed into
"ATN OSI Upper layer communication service". They could be moved to 3.6.2
to maintain parallelism:
3.6.1 IPS upper layers communications service
3.6.2 OSI upper layers communications service
3.6.3 IPS internet communications service
3.6.4 OSI internet communications service
3.
ACTION BY THE MEETING
3.1
The ACP SWGN1 is invited to review the comments provided and to update the
proposed amendment to SARPs accordingly.