[Smwg] [Css-csts] Using functional resources internally within a Provider CSSS
Holger.Dreihahn at esa.int
Holger.Dreihahn at esa.int
Wed Aug 8 07:07:21 UTC 2018
Hi Erik,
I fully agree that M&C as far as CCSDS is concerned should stay at service
level. The only thing I argue and hope, is that this CCSDS service level
is adequate for daily routine operations. Moreover I believe that an
'service level' monitoring is more efficient than a monitoring at the
level of the very low level parameters. To provide some insight, we have
the practical problem that the specialists in operations familiar with the
huge low level, historically grown set of parameters are departing to
management, retirement or wherever. The new staff are overwhelmed by the
number and complexity of low level monitoring parameters provided by the
systems. Here a clear and concise monitoring (one day control and
configuration) on service level may be beneficial, leaving the exceptional
cases requiring access and knowledge of low level parameters (equipment)
to the specialists. In my mind, monitoring Services based on Functional
Resources may clearly help here.
Maybe that makes it clearer where I am coming from. I don't even think
that we need many agency specific FRs if any. What we need for an
implementation is the mapping of FR parameters / directives / events to
real world (equipment) parameters, directives (or how you want to call
that) and events. Yes, this mapping is complex and does not complete
eliminate the need to monitor low level equipment parameters, but for most
cases it should do.
To give an idea, currently we have about 30000 - 40000 low level
parameters in a station. From the top of my head the FR model has around
600 parameters (let it be 1000 when complete). That sort of reduction to
meaningful Service Level Parameters together with the notion of a Service
being provided in a certain Configuration Profile looks to me at the right
level for efficient routine operations. Moreover it may foster automation
at a reasonable effort.
Your notion of 'firewalling' is fully supported, in fact I call it
layering. The FR layer is as specified by CCSDS, noting is equipment
specific. The layer below is equipment specific, at the end that's where
you need to look if things go wrong. But as long as things are nominal, as
an operator I want to be able to configure, provide, monitor and control
services at CCSDS FR level.
Best regards,
Holger
Holger Dreihahn
European Spacecraft Operations Centre | European Space Agency | S-431
+49 6151 90 2233 | http://www.esa.int/esoc
From: "Barkley, Erik J (3970)" <erik.j.barkley at jpl.nasa.gov>
To: "Holger.Dreihahn at esa.int" <Holger.Dreihahn at esa.int>
Cc: "CCSDS_CSTSWG (css-csts at mailman.ccsds.org)"
<css-csts at mailman.ccsds.org>, CSS-CSTS
<css-csts-bounces at mailman.ccsds.org>, John Pietras <john.pietras at gst.com>,
"CCSDS SMWG ML (smwg at mailman.ccsds.org)" <smwg at mailman.ccsds.org>,
Wolfgang Hell <wo_._he at t-online.de>
Date: 06/08/2018 23:59
Subject: RE: [Css-csts] Using functional resources internally
within a Provider CSSS
Hello Holger,
The main concern I have is how far (or depending on perspective, how
“deep”) do we as an international standards body have to go to enable
inter-agency cross support? I would venture that this is essentially to
the service level and not the level of implementing equipment. So to the
extent that there is particular encoding scheme for telemetry, yes, we
need to state that. Looking at basic signal characteristics, I think it
is sufficient to state that we are dealing with a left-hand circular
polarization, for example, rather than attempting to model that the
microwave mirrors for a particular type of instance of antenna need to be
set a certain way to properly achieve reception of the polarized signal.
I have no quarrel if a particular implementation wishes to detail
functional resources into its local monitor and control system, but I
think that any such instances should be carefully “firewalled” from the
service level FRs. Taking a look at the CSTS framework, I believe there
is already a start on this – although perhaps more work is needed. Below
is diagram extracted from 921.1-B-1, Annex D. Here it appears that there
is an anticipated agencyFunctionalites branch (1.3.112.4.4.2.2). Although
this is at the level of agency specific functions (at the service level),
I believe something very similar could be done to put in agency
internal/implementation level functions which the agency could populate
internally and which would fit with the particular agencies internal
review/implementation criteria, rather than being subjected to achieving
agreement at an inter-agency, CCSDS level.
Best regards,
-Erik
From: Holger.Dreihahn at esa.int <Holger.Dreihahn at esa.int>
Sent: Monday, July 30, 2018 2:39 AM
To: Barkley, Erik J (3970) <erik.j.barkley at jpl.nasa.gov>
Cc: CCSDS_CSTSWG (css-csts at mailman.ccsds.org)
<css-csts at mailman.ccsds.org>; CSS-CSTS
<css-csts-bounces at mailman.ccsds.org>; John Pietras <john.pietras at gst.com>;
CCSDS SMWG ML (smwg at mailman.ccsds.org) <smwg at mailman.ccsds.org>; Wolfgang
Hell <wo_._he at t-online.de>
Subject: Re: [Css-csts] Using functional resources internally within a
Provider CSSS
Hi Erik,
The idea of using the FRMs also for an internal implementation has of
course several potential 'pitfalls' but also some justification:
1) The FRMs must be able to give a comprehensive (high-level) view on a
ground station for a cross support scenario - otherwise it is useless
2) if 1) is true, we asked ourselves at ESA if we can use FRMs for a
general high-level view on all stations - those provided by external
providers and the ESA internal ones
3) Of course you need to implement in addition a much more detailed,
equipment specific low level M&C - finally you must be able to diagnose
and address all the low level details. Yes, the mapping of the low level
to the high level is needed and far from trivial.
4) We need to provide / use FRM based views anyway for external
stations...
Maybe we can discuss this layered approach if it is really so horrified or
if there is some sense to it.
Best regards,
Holger
Holger Dreihahn
European Spacecraft Operations Centre | European Space Agency | S-431
+49 6151 90 2233 | http://www.esa.int/esoc
From: "Barkley, Erik J (3970)" <erik.j.barkley at jpl.nasa.gov>
To: John Pietras <john.pietras at gst.com>, "CCSDS SMWG ML (
smwg at mailman.ccsds.org)" <smwg at mailman.ccsds.org>, "CCSDS_CSTSWG (
css-csts at mailman.ccsds.org)" <css-csts at mailman.ccsds.org>, Wolfgang Hell <
wo_._he at t-online.de>
Date: 12/07/2018 20:01
Subject: Re: [Css-csts] Using functional resources internally
within a Provider CSSS
Sent by: "CSS-CSTS" <css-csts-bounces at mailman.ccsds.org>
John,
In all honesty, I have to say I'm rather horrified by the prospect of
this. I firmly believe that CCSDS shall be required to consider only
service level interfaces and maintain only standards related to service
level concerns, and shall not delve into the internals of a particular
service provider. If an agency wants to apply the functional resource
model to the internals of its operation then I think as you have noted in
passing, a separate implementation specific MIB can be established.
I think if you play this out it is not long before you are into a
standards death spiral: for example, for a forward carrier, do I ask
CCSSD to worry about the DSN microwave mirror settings as a functional
resource –do I have to know that M5 (mirror 5) needs to be interlocked for
frequency band A for antenna X such that local radiation safety guidelines
are observed? Do I need to ask CCSDS to worry about the transmitter
type/equipment at an aperture such that an FR for transmitter warm up can
accurately set the warm-up time parameter? Frankly, to me this is like
asking the passengers of an airliner to be aware of drag versus distance
versus fuel efficiency, versus predicted head or tail wind etc in
calculating how many liters of fuel need to be on board the aircraft
versus I just want to take a flight to go from Los Angeles to London (the
service provider handles the details in providing the service to me).
As it is, I think the FRM, as good as it is, is not an easy read. I think
adding all the complexities for provider internals to the FRM will in fact
render us in the domain of (not easy)**2 (maybe cubed?) à verging into the
impossible to specify. I strongly urge and recommend the area to keep
the focus on the FRM to just those service level aspects needed for cross
support.
Best regards,
-Erik
From: CSS-CSTS <css-csts-bounces at mailman.ccsds.org> On Behalf Of John
Pietras
Sent: Thursday, July 5, 2018 6:49 AM
To: John Pietras <john.pietras at gst.com>; CCSDS SMWG ML (
smwg at mailman.ccsds.org) <smwg at mailman.ccsds.org>; CCSDS_CSTSWG (
css-csts at mailman.ccsds.org) <css-csts at mailman.ccsds.org>; Wolfgang Hell <
wo_._he at t-online.de>
Subject: Re: [Css-csts] Using functional resources internally within a
Provider CSSS
Dear all ---
A minor correction to the email below: the reference to “production
status” of FRs should be to “resource status”.
(For anyone who cares about the details, we have decided to reserve the
term “production status” for the parameter of a CSTS that represents the
rollup of the individual statuses of the production FR instances that
underlie that CSTS instances. E.g., only if all of the underlying
production resources are ‘operational’ can the production status of the
CSTS instance be ‘operational’. Initially we had also used the term
“production status” to also refer to the status of each individual FR
type, but we have decided to use “resource status” in the latter case.
This is targeted for cleanup in the candidate SANA Registry, which still
uses forms of ‘production status”.)
Best regards,
John
From: CSS-CSTS [mailto:css-csts-bounces at mailman.ccsds.org] On Behalf Of
John Pietras
Sent: Wednesday, July 04, 2018 11:03 AM
To: CCSDS SMWG ML (smwg at mailman.ccsds.org) <smwg at mailman.ccsds.org>;
CCSDS_CSTSWG (css-csts at mailman.ccsds.org) <css-csts at mailman.ccsds.org>;
Wolfgang Hell <wo_._he at t-online.de>
Subject: [Css-csts] Using functional resources internally within a
Provider CSSS
CSSA colleagues ---
This email is a follow-up to discussions that were held mostly in the
CSTSWG sessions in Gaithersburg. Because the discussions involved concepts
and usage of Functional Resources - which is a topic of interest to the
whole CSS Area - I am also including the members of the CSSMWG in the
distribution.
At the Gaithersburg meeting, some of the discussions regarding functional
resources centered on using FRs internally within an Agency network or
ground station (formally, a Provider CSSS or ESLT) to represent the
functions performed by an ESLT. I.e., a Provider CSSS might use FRs as the
organizing principle for its operational consoles and systems. However,
both Holger and Wolfgang have stated that ESA is interested in using FRs
for this purpose. We agreed in principle that this was valid, and indeed
began to account for the effect of such usage on the parameters, events,
and directives (PEDs) that would be defined for FRs (more on that in a
bit). However, in thinking about it a bit more, there are several issues
that arise that would need to be resolved in order to proceed on this
path.
As you may know, the initial concept of functional resource was that it is
an abstraction of externally accessible aspects of the functions
performed by an ESLT on behalf of a user Mission in a cross-support
context (where in this case cross support means that the Provider
CSSS/ESLT and the user Mission confine their interactions to the use of
CCSDS cross support services such as SLE and CSTS transfer services and
the functions performed by the ESLT are defined by CCSDS Recommended
Standards). This externally accessible aspect has several important
ramifications for how FRs are structured and used, including:
1. The only PEDs that are defined for FRs were to be those that were
accessible in the cross support context.
2. The identifiers of the FR instances are created in the context of
the user Mission. Originally, the FR instances were identified by
character strings that the Mission would specify that would have
significance to that Mission. That subsequently morphed into FR instances
being named by the combination of FR Type (OID valued) and FRIN (integer).
The FR Type is fixed but the FRINs are still (theoretically) left to the
Mission to set. Recently, we’ve come almost full circle by introducing FR
Nicknames – Mission-populated text strings set in the configuration
profiles that are aliases (at least in Service Management) for the [FR
Type: FRIN] names of the FR instances.
3. As a consequence of FRIN assignments being Mission-specific, the
mapping of any set of FRINs is only valid in the context of a given
Service Package. Functional resource instances technically don’t exist
when no service package is executing.
4. Functional resource instances are bound to specific real
resources only within the context of a Service Package. Even at the same
ESLT, the TM Sync and Channel Decoding FR instance with FRIN=5 might be
bound to the “real” decoder ABC for one Service Package but to decoder XYZ
for another Service Package.
These all work in the original FR concept, in which FRs are only used in a
cross-support (i.e., external) view of the functions being performed.
It was the ramifications of item (1) above that were first raised in the
consideration of allowing FRs to be used internally within a Provider
CSSS. One example is the production status parameter, which from the
perspective of the user Mission is read-only, but from the Provider it is
also a configuration parameter, since it is the provider that must be able
to HALT the resource. Another example is the case of configuring the
initial pointing angles of an antenna. From a cross support perspective
this is not done directly, but rather it is the product of a scheduling
process that involves selecting the ESLT that will support the contact,
the time of AOS, and the trajectory of the spacecraft. But internally, the
initial point angles can be considered the result of that process, full
stop.
In Gaithersburg we agreed that there could be multiple “views” or overlays
of the Functional Resources, but (tentatively?) agreed that the “core”
view would be one that (for lack of a better way of expressing it) looked
as though the FR was indeed instantiated as real resource. E.g.,
production-status of the FR would be configurable (because it would have
to be settable in order to take offline a piece of equipment that does the
corresponding function) and the antenna FR would have initial pointing
angles as configuration parameters because that is what would be “set” on
an antenna. It is these core PED definitions that would be used to
populate the SANA FR Registry. This core set would also act as the
superset of PEDs that various overlays could select from. E.g., a service
management cross support overlay would limit production-status and antenna
angle values to be read-only. Those overlay restrictions would be
specified in the appropriate Recommended Standards: e.g., the
aforementioned parameters would NOT appear in the Configuration Profile
book. This is the approach that currently forms our “guidance” for what is
in vs. out as far as formal FR PEDs.
What did not come up in our conversation was how such internal usage would
comply or conflict with the other aspects of the FR concept, as laid out
in points 2, 3, and 4, above?
In the thinking that I have done so far regarding this, my first
observation is that any such usage is outside the scope of the CCSDS
definition of FRs. In a sense we’ve already made a concession to the
internal usability of FRs by defining the core PEDs to be the ones that
are useful internally as well as externally. (We could have, for example,
alternatively defined the core PEDs to be only those that are externally
visible and required any internal-only PEDs to be defined in
Agency-specific subtrees/MIBs).
So our concern from a CCSDS (i.e., cross support) perspective should be to
ensure that using FRs internally doesn’t break or overly constrain the
usage of FRs for purposes of cross support.
My current thinking is that it would not be possible to use the “same” FR
instance designations for both internal and cross-support purposes,
primarily because the need to dynamically bind FR instances to real
resources on a Service Package basis, and only having FR instances exist
in the context of executing Service Packages, would not give ESLT
operators and operational software sufficient, unambiguous access to those
real resources 24/7.
Instead, FRs could be used internally by a Provider CSSS/ESLT by defining
an independent set of FR instances that persist outside the scope of
supported Missions’ Service Packages. Unlike the cross support context,
these persistent FR instances would be (quasi-)permanently bound to
specific real resources. That is, for example, the internally-defined TM
Sync and Channel Decoding FR instance with FRIN=10 at ESLT Q would be
bound to the real decoder ABC day in and day out. If a Provider CSSS has
multiple ESLTs and the purview of some operators is to extend across ESLTs
within that Provider CSSS, the FR Names would have to be unique across the
whole Provider CSSS. So for example, only ESLT Q would have the TM Sync
and Channel Decoding FR instance with FRIN=10.
These internally-defined FR instances would have names that would be
independent of the FR names given by the supported Missions and used in
their Configuration Profiles. That implies that during the execution of a
Service Package, a real resource would be represented simultaneously by
two FR instances. E.g., the functionality performed by decoder ABC in ESLT
Q would be represented to the ESLT operators/systems by the TM Sync and
Channel Decoding FR instance with FRIN=10, and represented to the Mission
(e.g., through MD-CSTS) by the TM Sync and Channel Decoding FR instance
with FRIN=5. When decoder ABC is not being used in the execution of any
Mission’s Service Package, the internal TM Sync and Channel Decoding FR
instance with FRIN=10 still exists and its PEDs can be accessed (e.g., for
testing purposes) even though no externally-visible FR instance exists to
map to that real decoder. Presumably, the operational software and console
displays would be designed to somehow relate cross-support FR instances
(when they exist) to internal FR instances, but that would be an internal
matter outside the scope of the CCSDS FR model and concepts.
An approach similar to the one above would allow the FR approach to be
used internally while not putting any additional constraints on the use of
FRs for cross support purposes. There may of course be other approaches
that do not adversely affect cross support.
Best regards,
John
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