[Sls-slp] Fwd: Re: Space Packet Protocol Green Book

Peter Shames peter.shames at jpl.nasa.gov
Mon Nov 3 19:42:17 UTC 2008

Hi GiPo,

Thanks for the very useful feedback.  I think that further dialogue on  
the GB will be very useful and am glad to hear that you support doing  
this and keeping the GB close to actual functionality that is defined  
in the SPP itself.  I believe that this is an important precept to  
keep in the forefront as we discuss the SPP GB draft.

At the same time I do believe that it is possible, within the context  
of the GB, to discuss things that could be done with the SPP to  
accomplish  certain mission and ground data system functions.  We just  
need to be very careful to clearly distinguish that which is clearly  
and unambiguously standardized as far as SPP functionality, and those  
approaches that are possible mission specific adaptations or uses, but  
that are not standardized or described in the required unambiguous,  
implementable, interoperable, fashion.

The version of the document that I attached had significant changes  
and comments and I would request that you and the rest of the WG use  
that as a source of input.  I used MS Word with "track changes" turned  
on, and I used highlighting and added comments, so it should be  
relatively easy to see the changes that i propose and the issues that  
I think need further discussion.

What I tried to do, as i stated in my note, was to provide re-wordings  
of all of the troublesome sections so that we had a final document  
that did not mis-led our users as to what the spec, as it exists  
today, is actually providing as services and what the users, if they  
wishes to define extended meanings, could construct on top of it.

Please use my draft, "SPP_DGB5-ps-16Oct08.doc", as the input to the WG  

Thanks, Peter

On 3 Nov 2008, at 10:10 AM, Gian.Paolo.Calzolari at esa.int wrote:

> Peter,
>         many of the things you say are correct (I say that - I admit  
> - without reading carefully the green book after the long reading of  
> your note :-).
> The fact is that the Source Packet (eventually named Space Packet)  
> was invented for Packet Telemetry and later used on  top of AOS  
> frames with some limited networking capabilities.
> In this respect I think it would be good if the green book, instead  
> of trying to find "valid" supporting motivation for the technical  
> aspects of SPP, would recover this historical aspects telling the  
> truth to the readers.
> This would be clearly inadequate for a Blue Book but it can be very  
> explanatory for a Green Book since - I agree with you - trying to  
> define today standard thorough routing mechanisms for the Space  
> Packet would be overkilling.
> It really looks as the green books deserves more discussion.
> Ciao
> Gian Paolo


Peter Shames
Manager - JPL Data Systems Standards Program
InterPlanetary Network Directorate
Jet Propulsion Laboratory, MS 301-230
California Institute of Technology
Pasadena, CA 91109 USA

Telephone: +1 818 354-5740,  Fax: +1 818 393-0028

Internet:  Peter.Shames at jpl.nasa.gov
"We shall not cease from exploration, and the end of all our exploring
will be to arrive at where we started, and know the place for the  
first time"

.S. Eliot

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