[Smwg] Response to AI 2016-0405-1.
john.pietras at gst.com
Thu Jun 8 14:07:05 UTC 2017
I am sorry that I was not able to participate in this discussion last month. I have comments on two items in particular in your briefing. Depending on the discussion that took place at the meeting, these comments may now be overcome by events, but I'll make them anyway and you can inform me as to whether they are still relevant.
My comments concern items 11 and 12, in which you state that we might not need the notions of Abstract Service Components and Service Component anymore, and use only the concept of Functional Resource. While - as you have noted in previous items in your briefing - the terms "Abstract Service Component" and "Service Component" will/should be replaced in the Functional Resource Reference Model with the terms "Functional Resource Stratum" and "Functional Resource Set", respectively, the concepts of Functional Resource Stratum and Functional Resource Set are important to the concept of even the simplified Configuration Profiles and should not be ignored in the ESCCS-SM Concept book.
To review those concepts:
- A Functional Resource Stratum is an abstract layer of functionality in the Functional Resources Reference Model. In general, each FR Stratum is defined in terms of the abstractly-defined functions that are performed by that stratum and the essential Service Access Point (SAP) that it provides and the essential SAP type that it accesses. The FR Strata are equivalent to the Internet Protocol Suite (a.k.a. TCP/IP) and ISO/OSI notions of layers, where (for example) in the Internet Protocol Suite the abstract Transport Layer can be filled by either TCP or UDP.
- Even though the SAPs/Accessors of the individual FR strata are fixed by the model, the specific functionality is not. It is this abstraction of functionality that allows multiple concrete Functional Resource Sets to plug into a specific stratum. So, for example, in our projected current set of simplified Configuration Profiles, we include Functional Resource Sets for Forward CCSDS 401 Space Link Carrier Transmission (in the Forward Physical Channel Transmission FR Stratum), Return CCSDS 401 Space Link Carriers (in the Return Physical Channel Reception FR Stratum), Forward TC Space Link Protocol and Forward AOS Space Link Protocol (both in the Forward Space Link Protocol Transmission FR Stratum), and Return Space Link Protocol (in the Return Space Link Protocol FR Stratum).
We know that in the (near) future we will also need to add FR Sets corresponding to CCSDS 405 (CDMA RF modulation used by NASA Space Network) to the respective Physical Channel FR strata and the Unified Space Data Link Protocol FR Sets corresponding to the respective Space Link Protocol strata. Even though our concrete efforts in the near term will be to create the simplified Configuration Profiles in terms of the identified "cookie cutters", those cookie cutters must still conform to the larger FR Strata model or we will paint ourselves into a corner from which we will not be able to escape. It is my opinion that the ESCCS-SM Concept Green Book should recognize that larger FR Strata/FR Set model since it is a fundamentally crucial concept for extending the sets of resources that Service Management can encompass. Of course, as you point out, the amount of work required to make the necessary terminology and notional changes in the Concept Green Book will be nontrivial, but I do think that the (revised) concepts should still be included.
I haven't seen that there are any summary minutes of the discussion at the Spring meeting on this topic, so I don't know what the WG discussed or concluded. If it would be appropriate, we can discuss this topic at the 27 June telecon.
From: SMWG [mailto:smwg-bounces at mailman.ccsds.org] On Behalf Of Marcin.Gnat at dlr.de
Sent: Thursday, May 04, 2017 9:39 AM
To: smwg at mailman.ccsds.org
Subject: [Smwg] Response to AI 2016-0405-1.
In response to AI 2016-0405-1, I uploaded my short power point with few points regarding the consistency between Concept GB and current developments of Config Profiles.
I believe we have time for discussion reserved on Thursday after first Coffee Break.
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