Due to lack of the ability to have multiple independent implementations of GMSEC due to its message-building API functions in source code, it would be appreciated if there were an XML PSM available. This would allow for an independent implementation apart from the single known implementation at this time. At this time, there is no known PSM that enables implementation of C2MS at this time that does not depend on FOSS or government-licensed IP.

This is based on inputs from C2MS-2.

Based on review of latest specification, the problem detailed in C2MS-5 is still present. This problem makes it not possible for a client application to properly be developed to support all MEPs. If a client application is developed to support MEP2, then it will ignore all future responses after the first ACK comes in when communicating with a server that supports MEP4 or MEP5. If a client application is developed to support MEP4 and MEP5, then it will never think that a request finished when communicating with a server that supports MEP2.

As is currently specified, via table 6-9 on page 20, the Acknowledge is listed as a Final Status. Though it is only a final status in MEP2.

Possible solutions:
1. Remove MEP2. This would make Acknowledge in Table 6-9 have a Final Status of "No"
2. Add an additional status code of Acknowledge Complete (perhaps #7). In this option, Acknowledge (#1) would have Final Status of "No", though new Acknowledge Complete (#7) would have Initial Status of "Yes", Intermediate Status of "No", and Final Status of "Yes".

For most of the message types in C2MS, this convention is followed. The exceptions are:

-Archive Message Retrieval Request
-Archive Message Retrieval Response

These were likely left this way because they already have "Message" in the name, though with a different meaning. Archive Message Retrieval Request Message does sound redundant. Perhaps renaming to any of the following would help:

• Archived Messages Request Message
• Archive Retrieval Request Message
• Archive Request Message
• Archive Message Request Message

Not using "Archive Message" in the title is a bit confusing because there is Archive data that is not simply archived messages, see "Archive Mnemonic Value Request Message"

Note that when originally entered, this issue listed all the following... but in 1.1, the only messages not ending in "Message" are the Archive request/responses.

-Archive Message Retrieval Request
-Archive Message Retrieval Response
-Telemetry Message for CCSDS Packet
-Telemetry Message for CCSDS Frame
-Telemetry Message for TDM Frame

I do not expect this can be addressed by the FTF. Suggest vote to defer to a future revision.

The messages for mnemonic access do not appear to include a request/response for "setting" the value of a parameter (mnemonic) from an application participating using C2MS. This capability is used for ground and other types of non-telemetered parameters (mnemonics).

if I do not write it down, I will forget.

I do not expect this can be addressed by the FTF. Suggest vote to defer to a future revision.

For a complete implementation of C2MS on the systems I use, we need some kind of Procedure Script Execution set of messages. These would include being able to launch procedures, monitor them, show progress, etc. This could be a topic of some significant discussion and is entirely new scope. The closest analogue I have so far found is the Activity Tracking stuff in the CCSDS Mission Operations Common Services.

if I do not write it down, I will forget.

Requesting data, such as telemetry, via pub/sub requires knowing the publisher's server name. There should be a way to request data without this being already known. This could potentially be solved by a registry concept, as in C2MS11-1, but this particular issue proposes adding a service-matching capability wherein the requester is asking for a subscription to some data and the request results in linking the subscription to a service that provides that data.

This to be consistent with the XTCE Specification. Moreover Mnemonic isn't accurate as the very definition of mnemonic is a shorthand "code" for the actual parameter name.

Recommend close/deferring this issue, but believe it's important to capture our rationale as the community will ask why the inconsistency between SDTF specifications.

C2MS should offer a mechanism for clients and/or servers to be able to check validity of a subscription.

I do not expect this can be addressed by the FTF. Suggest vote to defer to a future revision.

It seems that there is a consensus that we need database data dictionary informational messages. It seems to be in work. Capturing the item here.

if I do not write it down, I will forget.