Craig
I'm sorry that I missed the June meetings there - so please excuse any
duplication or overlap below as the topics may have been discussed during
the working groups. Some thoughts on the question of how data formats
arise, and the appropriate point within the LRIT Infrastructure follows:
As a practical matter many ASPs today support most, if not all, of the
satellite providers likely to meet the performance standards for LRIT (and
thus be potentially CSPs or support CSPs). Therefore I would disagree that
this aspect is overly burdensome. Converting data is not, in context,
likely to determine the success or failure of an ASP considering all other
factors within an ASP's list of responsibilities (securing customers,
maintaining a data center, certification into LRIT).
However; in our view that discussion itself is rendered moot by the bigger
question of what is technically feasible for a CSP.
The view here is that CSPs will be unable to convert data to the proposed
format (or any other standard format for that matter).
Each CSP provides a communications path via a specific satellite network.
However CSPs do not, in most instances, have knowledge of payload
interpretation, protocol or format of the data exchanged between the ASP and
the Shipboard Equipment. Such aspects are handled by firmware, scripting or
other configuration mechanisms that are specific to each equipment vendor.
Hence the data transmitted via any given CSP may vary from device-to-device
and change over time as new software or firmware revisions are made to the
onboard equipment.
To our knowledge, all potential CSPs provide flexibility in the
representation of the LRIT requirements over their networks (e.g. the raw
encoding of a position report). Most potential CSPs also provide several
different delivery mechanisms which are proven both technically and
commercially. As the CSP cannot generally control the
scripting/firmware/configuration options present on each piece of Shipboard
Equipment it becomes technically infeasible to assign any data translation
capabilities to the CSP.
Furthermore; even if a CSP did have knowledge of the payload protocol - and
thus could translate it - that approach may have unintended consequences.
If would lead to a lowest-common-denominator approach within the data
available to ASPs. Shipboard Equipment and CSPs often make data available
in addition to the fields required for LRIT. We anticipate that ASPs are
likely to use this additional data to offer services complementary to LRIT -
in terms of their offerings to fleet owners and operators. Consequently; we
do not believe that it is desirable for a CSP to remove all additional data
as that would limit the overall utility of the LRIT system to fleet owners
and operators. Such a step would also reduce the commercial opportunities
available to ASPs.
Our view is that the earliest point in the LRIT infrastructure where
sufficient information is available to standardize a format is at the ASP.
Of note the ability to satisfy the Performance Standards arises through the
use of two system components in conjunction:
a) Shipboard equipment; including configuration options (scripts, firmware
versions etc)
b) The CSP; including the account configuration and selected delivery
formats etc (i.e. VPN, Internet, header formats)
There are two additional notes here - to avoid potential misinterpretation
of the above:
1) A CSP may also act as an ASP. In that case the ASP+CSP can take
responsibility for the configuration of shipboard equipment - and thus is
able interpret the payload data fully within the ASP aspects of its dual
role.
2) It may initially appear that Inmarsat-C equipment operating in
according to the baseline PDR specifications is an exception - as this is a
rare case of a network operating defining a position reporting protocol.
However; it should be noted that most deployed Inmarsat-C equipment extends
the Inmarsat-C baseline standards in vendor proprietary ways - and this is
specifically allowed within the Inmarsat-C baseline PDR specifications.
3) Finally; any translation to a common format could not be performed
once per "physical" satellite network. The "CSP" for example in
Inmarsat
could be a Land Earth Station operator, other distribution partner or
Virtual Network Operator (i.e. Inmarsat-D+). The same comment applies to
other satellite providers who elect to have distribution partner(s) act as
the CSP. It should be noted that this may be required by the
telecommunications regulators in some countries (where a specific legal
entity or reseller holds the concession to land traffic from a given network
within a defined country). Consequently, care should be taken here not to
equate "CSP" in the LRIT lexicon with "Satellite Network" in the sense
of
the physical satellite constellations available - there may be many CSPs
sharing the same physical satellite network. Hence the apparent simplicity
of the "one-CSP" vs. "many-ASP" argument falls down. It is actually
quite
possible that there would be fewer ASPs than CSPs in practice once LRIT is
deployed.
Best Regards
Jeff Douglas
Director
ABSOLUTE SOFTWARE INC
www.absolutesw.com <
http://www.absolutesw.com/>
_____
From: ccglrit-gcclrit-bounces(a)lists.ncf.ca
[mailto:ccglrit-gcclrit-bounces@lists.ncf.ca] On Behalf Of Hayley, Craig
Sent: Friday, June 01, 2007 09:43
To: ccglrit-gcclrit(a)lists.ncf.ca
Subject: Re: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
You make a fair point... I would suggest other interested parties (such as
ASPs wishing to bid on the ASP function for the IDC case) voice their
position. If we allow CSPs to send the shipborne data to the ASP based upon
any "format" or protocol than the ASP will have to absorb the cost of
supporting multiple "formats" and communication protocols. The extra
expense, of course, would likely be pushed back to the customers
(contracting governments).
This topic affects only ASPs and CSPs wishing to form the communication path
to the International Data Centre (not national or regional data centers).
Based upon e-mails written on this reflector and the discussion in the
Hamburg meeting, the document will be aligned with the "consensus" view.
Regards,
Craig Hayley
System Engineer
Canadian Coast Guard
_____
From: ccglrit-gcclrit-bounces(a)lists.ncf.ca
[mailto:ccglrit-gcclrit-bounces@lists.ncf.ca] On Behalf Of Brian Mullan
Sent: Friday, June 01, 2007 10:37 AM
To: Hayley, Craig
Cc: ccglrit-gcclrit(a)lists.ncf.ca
Subject: Re: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
Thanks, Craig
Good clarification on the data format from the ships. However, you now infer
that CSPs will perhaps be asked to format messages from ships - but not all
CSPs have signed up to do this (I know of only one). It is the understanding
of many CSPs that the manipulation of the "raw" data from ships starts at
the ASP level. Also, the LRIT coordinator has said in the past that
coordination ("oversight") starts at the ASP level. The CSP has largely been
seen (until now) as purely the comms pipe that provides the LRIT data from
ships to the ASP and to start involving CSPs in manipulating LRIT data would
extend the oversight role.
Writing in specifications for all CSPs would therefore appear to be
premature!
Kind regards
Brian
Brian Mullan
Head, Maritime Safety Services
Inmarsat, 99 City Road, London EC1Y 1AX, UK
Tel: +44 (0)20 7728 1464
Fax: +44 (0)20 7728 1689
Mob: +44 (0)7711 495836
www.inmarsat.com
_____
From: Hayley, Craig [mailto:HayleyCR@DFO-MPO.GC.CA]
Sent: 01 June 2007 13:52
To: Brian Mullan
Cc: ccglrit-gcclrit(a)lists.ncf.ca
Subject: RE: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
Hi All,
I'm please to see a good discussion has developed around this topic.
Hopefully, more discussion on other topics in the documents will be
initiated over the coming week before we meet in Hamburg.
Given the e-mails on this topic, the text (including wording in the table)
should be altered to eliminate any confusion.
I agree that the specific data elements (latititude, longitude, year, month,
day, hour, minute, unique equipment identifier) that the shipborne equipment
transmits is the important information. The "format" of how those elements
are displayed is accomplished by land based software (not shipborne
equipment software). Essentially, an application piece of software will take
those data elements, process them and display them in a given "format". It
has been decided that SOAP messages (using XML format) will be the back bone
of the LRIT communication system. Thus, the various data elements contained
in a given LRIT message will have to be "formatted" as such. The question of
whether application software residing at the CSP or ASP (not software on the
shipborne equipment) begins to format the data elements into an LRIT message
(SOAP using XML) as defined in the communications document is another issue.
Currently, the document is written such that the CSP (for the International
Data Centre case) begins to build SOAP messages and pass them to the ASP. We
have to define an interface between the ASP and the CSP for the
International Data Centre case. If we allowed CSPs to transmit information
to the ASP using different formats, protocols, etc than it wouldn't be fair
to the ASP. This would add an extra cost burden on the ASPs given that they
would have to support multiple formats, protocols, etc. Please note that
national data centers and regional data centers are free to define and allow
different formats, protocols, etc from the CSP to the ASP.
The intention of the LRIT communications document shall be to specify the
data elements transmitted by the shipborne equipment as stated in Brian's
previous e-mail:
Shipborne Data Elements:
Latitude -> degrees, minutes and decimal minutes to two decimal places N /
S
Longitude ->degrees, minutes and decimal minutes to two decimal places E /
W
Unique equipment ID -> number
Year -> 4 digit year number
Month -> 2 digit month number
Day -> 2 digit day number
Hour -> 2 digit hour number
Minute -> 2 digit minute number
Regards,
Craig Hayley
_____
From: Brian Mullan [mailto:Brian_Mullan@inmarsat.com]
Sent: Friday, June 01, 2007 6:18 AM
To: Hayley, Craig
Cc: ccglrit-gcclrit(a)lists.ncf.ca
Subject: RE: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
Hi, Hayley
Many thanks for your email. I can agree that the text of the document is
clear; but that the wording in the table is not consistent and appears even
to contradict the text you quote. My copy of the document shows wording for
1.1.1.1 that is different:
"The intent of this document is to outline the technical specifications for
communication within the international Long-Range Identification and
Tracking (LRIT) system as stated in the terms of reference of resolution
MSC.211(81)."
Your reference is new text in 2.2.2.4 in the copy that I received
(15-02-2007 LRIT ad hoc WG)
In Table 2, the heading indicates "Parameter provided by LRIT Shipborne
Equipment" and then describes the various elements, including specifying the
format. It is clear to me and others that this method of presenting the
information in the table means that the information transmitted by the
shipborne equipment *must* follow the format written in the table. This is
where the difficulty lies - the wording is over-prescriptive and does not
accord with the wording in 2.2.2.4. My original email showed how, in
Inmarsat C position reporting at least, the way the information is
transmitted. Other shipborne systems probably will have their own format for
presenting data to the ASP.
May I suggest, please, that we stick to requiring that the specific data
elements (unique identifier, latitude/longitude and date/time of the
position) are transmitted from the ship and then only start to prescribe the
format for onward transmission from the ASP? In other words, as long as the
shipborne equipment transmits, as a minimum, the required elements, any
format is acceptable. This allows for all approved shipborne LRIT systems to
be offered, no matter in which order or format the data is presented. This
approach will also allow the table to be in accord with the new wording in
2.2.2.4
I hope that this is clear. Your hard work is very much appreciated and it is
clearly understood that the document remains a "work in progress". Please
don't take my input as criticism - it is not! All I seek is clarity of the
wording for all.
With best wishes
Brian
Brian Mullan
Head, Maritime Safety Services
Inmarsat, 99 City Road, London EC1Y 1AX, UK
Tel: +44 (0)20 7728 1464
Fax: +44 (0)20 7728 1689
Mob: +44 (0)7711 495836
www.inmarsat.com
_____
From: Hayley, Craig [mailto:HayleyCR@DFO-MPO.GC.CA]
Sent: 31 May 2007 19:05
To: ccglrit-gcclrit(a)lists.ncf.ca
Cc: Brian Mullan
Subject: RE: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
Hi Brian,
Thanks for the e-mail. I hope more people will take the time to read the
documents and provide comments. I assume you are referring to the LRIT
communication document.
Please note the following text in the LRIT communications document:
1.1.1.1 The parameters added by the LRIT shipborne equipment
include the latitude, longitude, Time Stamp when the position was generated,
and the shipborne equipment identifier. The "Format" of these parameters as
outlined in table 2 indicates how the parameters shall be formatted while
the information is contained within the LRIT message and does not specify
the format of how the shipborne equipment transmits the information.
Regarding your concerns with the format of the date/time... The only
difference that I can detect between the date/time you state and what is in
Table 2 of the LRIT communications document is the separators ("-" versus
":") for the year, month, day, hour and minute. The separator used to
separate the year, month, etc in the date stated in table 2 is not important
and in no way linked to the format coming out of the shipborne equipment.
The format is with respect to SOAP messages communicated along the various
LRIT communication segments. CSPs for the IDC shall have to "build" SOAP
messages complying with table 2 in the communications document using the
format from the ship borne equipment. The important thing with the time
stamp is that seconds are not transmitted.
Regarding your concerns with the format for latitude... We had a discussion
on your e-mail and the intention was to implement your recommendation. I
can't recall why the "seconds" component of the latitude didn't change
to
decimal minutes with a precision of 2 decimal places. The most likely reason
is that I forgot to incorporate this change in the document due to the
numerous requests. My apologies on this topic. I will make the change for
latitude to decimal minutes unless someone raises a compelling reason not to
change. Any body from the Communications group recall if there was a
specific reason why we didn't make the change (Jilian, Guy, etc.)???
I would like to high light to everyone that these documents are in constant
flux as a result of many requests from different inputs at the Ad Hoc
meeting. Thus, it is important to fully read the documents that come out of
each meeting to ensure that any particular topic of interest is addressed in
a satisfactory manner.
Thanks,
Craig Hayley
System Engineer
Canadian Coast Guard
709-772-7740
_____
From: ccglrit-gcclrit-bounces(a)lists.ncf.ca
[mailto:ccglrit-gcclrit-bounces@lists.ncf.ca] On Behalf Of Brian Mullan
Sent: Thursday, May 31, 2007 12:35 PM
To: ccglrit-gcclrit(a)lists.ncf.ca
Subject: Re: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working
Group onEngineering Aspects of LRIT, Hamburg Germany
Thanks, Tracy
In table 2 I note that the format of date/time is still shown as
YYYY-MM-DD-HH-MM. My earlier email (attached) made comment on this. Also in
Table 2, note appears to have been taken of my comments regarding
latitude/longitude position for Longitude only, but ignores Latitude.
We must not start requiring reformatting for transmitted data that is
already designed into existing shipboard equipment - PLEASE!
Many thanks
Brian
Brian Mullan
Head, Maritime Safety Services
Inmarsat, 99 City Road, London EC1Y 1AX, UK
Tel: +44 (0)20 7728 1464
Fax: +44 (0)20 7728 1689
Mob: +44 (0)7711 495836
www.inmarsat.com
_____
From: ccglrit-gcclrit-bounces(a)lists.ncf.ca
[mailto:ccglrit-gcclrit-bounces@lists.ncf.ca] On Behalf Of Peverett, Tracy
Sent: 29 May 2007 22:27
To: ccglrit-gcclrit(a)lists.ncf.ca
Subject: [Ccglrit-gcclrit] June 12-14 meeting of the Ad hoc Working Group
onEngineering Aspects of LRIT, Hamburg Germany
Second of two e-mails
As promised, attached please find the updated LRIT Communications
specification.
Best regards
Tracy
Tracy Peverett
Senior Policy Analyst
Canadian Coast Guard
Tel: 1-613-990-4046
Fax: 1-613-998-3255
e-mail: peverettT(a)dfo-mpo.gc.ca
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