[Moims-sc] [EXTERNAL] [CCSDS] MAL Header - Optimization

Shames, Peter M (US 312B) peter.m.shames at jpl.nasa.gov
Mon May 22 12:25:04 UTC 2023


If the defined values are within USHORT range that aspect sounds fine, and you won’t have to change the current list.  But the change to these field lengths means that you will not have interoperability between different versions.

I saw nor mention of version number changes.  So I find this change of the fundamental header structures and field sizes, without a change of version number, to be out of compliance with normal CCSDS practices.

I will point out that there are changes in document version numbers for other standards, but these do not involve changes in PDU format nor version numbers.

Regards, Peter


From: "Coelho, César" <cesar.coelho at cgi.com>
Date: Monday, May 22, 2023 at 1:42 AM
To: Peter Shames <peter.m.shames at jpl.nasa.gov>, MOIMS-SC MOIMS-SC <moims-sc at mailman.ccsds.org>
Subject: RE: [EXTERNAL] [Moims-sc] [CCSDS] MAL Header - Optimization

Hi Peter,

All the previously defined service areas, services, and operations are within the UOctet range.
They can be casted into the UOctet type.

Best regards,
César Coelho


From: Shames, Peter M (US 312B) <peter.m.shames at jpl.nasa.gov>
Sent: Saturday, May 20, 2023 1:16 AM
To: Coelho, César <cesar.coelho at cgi.com>; moims-sc at mailman.ccsds.org
Subject: Re: [EXTERNAL] [Moims-sc] [CCSDS] MAL Header - Optimization

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It’s your choice, of course, but doesn’t this totally blow backward compatibility?   The only way this would be allowed in most CCSDS specs is if it were given a different version number.

Regards, Peter


From: MOIMS-SC <moims-sc-bounces at mailman.ccsds.org<mailto:moims-sc-bounces at mailman.ccsds.org>> on behalf of MOIMS-SC MOIMS-SC <moims-sc at mailman.ccsds.org<mailto:moims-sc at mailman.ccsds.org>>
Reply-To: "Coelho, César" <cesar.coelho at cgi.com<mailto:cesar.coelho at cgi.com>>
Date: Friday, May 19, 2023 at 7:30 AM
To: MOIMS-SC MOIMS-SC <moims-sc at mailman.ccsds.org<mailto:moims-sc at mailman.ccsds.org>>
Subject: [EXTERNAL] [Moims-sc] [CCSDS] MAL Header - Optimization

Dear SM&Cers,

I would like to propose an optimization in the MAL Headers.
Basically, to change the type of Service Area, Service, and Operation, to UOctet (range is 0 to 255):

Field
Type
Description
From
Identifier
Message Source
Authentication Id
Blob
Authentication Identifier of Message Originator
To
Identifier
Message Destination
Timestamp
Time
Message generation timestamp
Interaction Type
InteractionType
Interaction Pattern Type
Interaction Stage
UOctet
Interaction Pattern Stage
Transaction Id
Long
Unique to consumer
Service Area
UShort
Service Area
Service
UShort
Service
Operation
UShort
Service Operation
Service version
UOctet
Service version
Is Error Message
Boolean
‘True’ if this is an error message; else ‘False’
Supplements
List<NamedValue>
Optional supplementary fields


This optimization also allows the Fully Qualified Short Form Part to be defined using a UInteger (4Bytes) instead of a ULong (8Bytes).
From:  Area Number (UShort – 2B), Area Version (UShort – 2B), Service Number (UShort – 2B), SFP (Short – 2B)
To: Area Number (UOctet – 1B), Area Version (UOctet – 1B), SFP (Short – 2B)

In terms of changes, this is easy to fix in the books, and also in the code.
Let me know if you disagree with this optimization.
If I receive no reply within the next 2 weeks, I will assume that you agree and I will update the book accordingly.

Best regards,
César Coelho


Dr. César Coelho
CGI Deutschland B.V. & Co. KG  | Space
Mornewegstr. 30 | 64293 Darmstadt | Germany
T: +49 173 54100 45 | email: cesar.coelho at cgi.com<mailto:cesar.coelho at cgi.com>

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