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

[Churlaud Olivier]

We have a service version number in the header, so if we bump the version of all MO services (which is expected), it will have the impact you expect, won’t it ?

The important interoperability contract is at Service level, not MAL level. We could add also a MAL-version field in the PDU but I think the overhead will not bring any value since we already have the service version defined, but I might be wrong.

Best regards
Olivier

De : MOIMS-SC <moims-sc-bounces at mailman.ccsds.org> De la part de Shames, Peter M (US 312B) via MOIMS-SC
Envoyé : lundi 22 mai 2023 14:25
À : Coelho, César <cesar.coelho at cgi.com>; moims-sc at mailman.ccsds.org
Objet : Re: [Moims-sc] [EXTERNAL] [CCSDS] MAL Header - Optimization

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<mailto:cesar.coelho at cgi.com>>
Date: Monday, May 22, 2023 at 1:42 AM
To: Peter Shames <peter.m.shames at jpl.nasa.gov<mailto:peter.m.shames at jpl.nasa.gov>>, MOIMS-SC MOIMS-SC <moims-sc at mailman.ccsds.org<mailto: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<mailto:peter.m.shames at jpl.nasa.gov>>
Sent: Saturday, May 20, 2023 1:16 AM
To: Coelho, César <cesar.coelho at cgi.com<mailto:cesar.coelho at cgi.com>>; moims-sc at mailman.ccsds.org<mailto: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
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