[Sls-slp] RE: Encapsulation Service
Durst, Robert C.
durst at mitre.org
Wed Apr 19 20:40:12 UTC 2006
>>While this is probably the pragmatic approach, the
>implication of this is
>>that two implementors can provide the same CCSDS service in a
>way that is
>>not, and cannot be configured to be, interoperable. I find this
>>disturbing. This possibility at least needs to be noted,
>and added to
>>the list of parameters that are managed among implementors.
>>like a rather serious flaw to me. I would much rather see a
>>to implement both and an option to use either on a per-mission
>>basis. Failing that, I'd like to see a Protocol Implementation
>>Conformance Statement developed and made mandatory, so that
>there is no
>>ambiguity about what an implementor has implemented.
>Actually it is already a managed parameter. It's the PVN ,
>version number in the Space Link Identifers blue book. It tells the
>receiver how to interpret the packet, i.e., how to find the
>in order to extract it and assemble it. Encapsulation Packets
>have a unique
>PVN, so do Space Packets and they are distinct.
>So CCSDS has provided a mechanism for space agencies to be
>But that doesn't proclude some hypothetical rogue space agency
>there first" who only chooses to support bit streams instead of CCSDS
>recognized packet version numbers.
OK, that covers my concern.
> >>I think that it would be useful to summarize the "managed
> >>somewhere, to make it clear specifically what bilateral
> >agreements are
> >>required to ensure interoperability. This may be part of the
> >>within the CCSDS community, but if we want other folks to use
> >this, making
> >>it clear what needs to be agreed upon out-of-band seems important.
>Didn't see any comment on this (but then, my comment didn't require
>any). Any thoughts on an annex to summarize these?
>I think we are between messages. You are probably reading that second
>message now. Actually Yamada has already captured the managed
>Table 5-1 of the Encapsulation Packet service, but he didn' t
>controlling document for each parameter and more cleanly
>applies when one use Space packets vs Encapsulation packets.
I believe that this fully covers my concerns. Thanks to you, Takahiro,
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