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transcript
NASA Space Network Ground Segment Sustainment (SGSS)
Schedule Request
SMWG
Boulder, CO
31 October – 4 November 2011
John Pietras
GST, Inc.
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Agenda
Purpose
Background
Approach
Schedule Request Class Diagrams
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Purpose
To describe the (still evolving) NASA Space Network Ground Segment Sustainment (SGSS) Project requirements for a “schedule request message”
Compare the draft SGSS schedule request message with the SCCS-SM-B-1 Create Service Package invocation
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Background
The proposed Blue-2 refactoring approach provides a framework adding new managed services and extending the managed services already covered by Blue-1
NASA SGSS is to implement SCCS-SM Blue-1 “to the greatest extent possible”, but SGSS will have schedule optimization mechanisms that are not supported by Blue-1’s Create Service Package operation
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Approach
Develop SGSS Schedule Request class diagrams equivalent to that of the Space Link Session Service Package Request selection in the <<ServicePackageRequest>> of SCCS-SM-B-1
Based on draft SGSS schema of 6 September 2011 Class diagram view is easier to see “big picture” concepts than schema
details Easier to compare to <<ServicePackageRequest>> class diagram
Covers only those features of importance to SGSS No attempt (in this iteration) to add back SCCS-SM-B-1 features not
used by SGSS
SCCS-SM refactoring concepts applied where it seems appropriate
A few minor differences between classes and schema types for purposes of cleaner class diagram representation
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<<ServicePackageRequest>> Class Diagram
scenarioId
ServiceScenario
transferServiceProfileRef
SlsTsProfileRespecification
0..*
1
1
1..*
1
1..*
spaceCommunicationServiceProfileRefspaceCommServiceStartTimespaceCommServiceStartTimeLeadspaceCommServiceStartTimeLagminimumServiceDurationpreferredServiceDurationtransferServicesDeferred : BooleansequenceOfEventsDeferred: BooleantimeReference
SpaceCommunicationServiceRequest
spaceLinkEventsProfileRef
SpaceLinkEventsProfileReference
0..*
1
parameterDistinguishedNameparameterValue
RespecifiedParameter
1..*
1
SpaceCommunicationServiceProfileRespecification
0..1
1
handoversPermittedImportanceprimeScenarioRef
SpaceLinkSessionServicePackageRequest
acceptabilityConstraintsType
AntennaConstraints0..11
antennaRefconstraintType
Antenna
1
1..*
trajectoryRef
TrajectoryReference
1
1..*
1..*
1
antennaReftransferServiceProfileRefaccessStartTimeaccessStopTime
RetrievalServicePackageRequest
RetrievalTsProfileRespecification
0..1
1
1..*
1
<<ServicePackageRequest>>
1
1
{xor}
1
1
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SGSS Schedule Request (Top Level)
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EventSpecification
1
1
SpecificTime
1
1
<<extensionPoint>>RecurrentTime
1
1
{xor}
timeleadTolerance (opt.)lagTolerance (opt.)
StartTime
isPreferred (opt.)windowStartPref (opt.)
StartTimeWindow-Constraints
1
1
1
1..*{xor}
isExcluded (opt.)
TimeWindow-Constraints
1
0..1
identifierfreezeInterval
SgssScheduleRequest
<<extensionPoint>> LinkedEvent
1
0..*
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SGSS Schedule Request Comparison with CSP
No alternate scenarios SN will implement only a single “scenario”
No explicit trajectory references SN uses maintains a single trajectory for each supported spacecraft
Freeze interval parameter regulates how long CM can modify a request
Request can be for a single (specific) service package or a recurring service package
The specific request as a whole has a start time that is requested In contrast with the CSP, in which the components of the request have start times and
the start time of the service package is result of what is scheduled The start time can be around a single (preferred) start time or within any of a set of start
time windows
The specific request can be constrained to be within one of a defined set of windows
The SN groups services (carriers) by Event (the group of services provided through a single TDRS), not by single antenna (as in SCCS-SM SCSP)
Antenna selection is addressed later
Multiple events can be specified within the request, but one is primary ands the others are “linked” to it
No reason to put multiple events in the same package unless they are somehow related
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Time Window Classes
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isPreferred (opt.)windowStartPref (opt.)
StartTimeWindow-Constraints
isExcluded (opt.)
TimeWindow-Constraints
<<extensionPoint>>TimeWindow
1
1
1
1..*
startTimeduration
DefaultTimeWindow
eventRefstartOffsetduration
EventTimeWindow
timeWindowSetRef
ReferencedTime-WindowSet
weekdaystartTimeduration
WeekdayTimeWindow
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Recurrent Time
10
startTimeduration
<<extensionPoint>>RecurrentTime
isExcluded (opt.)
TimeWindow-Constraints
<<extensionPoint>>TimeWindow
1
0..1
eventsPerOrbit
Orbit
eventRef
OrbitEvent
PeriodeventsPerPeriod
Periodic
minimummaximumpreferred
DurationMinMaxPref
TimeBetweenEvents
1
0..1
StartTimeOffset1
1
networkResource-Ref
Network-ResourceView
StartTimeOffset1
1
initialUtilizationutilizationDuringEventutilizationBetweenEvents
Resource-Utilization
minimummaximum
Capacity
1
1
Window StartTimeOffset1
1
11..*TimeBetweenEvents
0..1
1
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Event Specification
11
identifier
EventSpecification
ExplicitEventSpecification
SplittableEventConstraints
1
0..1
maximumNumberOfSegments
MaximumNumberOf-Segments
minimummaximumpreferred
MaximumConcurrent-Segments
1
0..1
1
10..1{xor}
SegmentDuration
SegmentSeparationDuration
1
1
serviceIduserServiceProfileRef
ServiceSpecification
1
1..*
NetworkResourceConstraints
1
0..1
resourceRef
ResourceRef
1
1..* UserResourceConstraints
resourceRef
ResourceRef
1
1..*
1
0..1
eventSpecificationReference
ReferencedEventSpecification
1
1
1
1
1
1{xor}
minimummaximumpreferred
DurationMinMaxPref
points to Event Specification Profile
points to User Service Profile
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Service Specification Comparison with CSP
In today’s SN, services (carriers) in an Event can be specified either individually, or grouped in a pre-defined Prototype Event
Service (carrier) configuration parameters can be respecified only when the services are explicitly defined in the request
The Prototype Event notion is carried in SGSS as the Referenced Event Specification
SCCS-SM provides for scheduling groups of services (via predefined Space Communication Service Profiles), and allows respecification of parameters within those groups
This leads to a more-complicated respecification mechanism Can/should Blue-2 adopt the simpler SN/SGSS approach?
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Service Specification
13
1 1
serviceIduserServiceProfileRef
ServiceSpecification
DiscreteTime-ServiceSpecification
offsetleadTolerancelagTolerance
RelativeTime-WithTolerance StartTime
Duration
Minimumpreferred
DurationMinPref
11
serviceRef
CoupledTime-ServiceSpecification
StartTime
Duration
11
11
serviceRef
BoundTime-ServiceSpecificationDuration
1 1
<<extensionPoint>>ServiceTimeSpecification
1
1
RespecifiableParameter
1
0..*
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Service Specification Comparison (continued)
Services can be related to each other Alternative Coupled Bound
In SCCS-SM, all carriers can only be offset by a fixed time from the scheduled start time of the Space Communication Service
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Event Specification Profile
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eventSpecificationIdentifier
EventSpecificationProfile
SplittableEventConstraints
1
0..1
maximumNumberOfSegments
MaximumNumberOf-Segments
minimummaximumpreferred
MaximumConcurrent-Segments
1
0..1
1
10..1{xor}
SegmentDuration
SegmentSeparationDuration
1
1
serviceIduserServiceProfileRef
ServiceSpecification
1
1..*
NetworkResourceConstraints
1
0..1
resourceRef
ResourceRef
1
1..* UserResourceConstraints
resourceRef
ResourceRef
1
1..*
1
0..1
1
1minimummaximumpreferred
DurationMinMaxPref
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Linked Event
16
EventSpecification
eventRef
<<extensionPoint>> LinkedEvent
1 1
preference
AlternateEventConstrainedRelative-
Time
isRequired
CoupledEvent
1
1
isRequired
BoundEvent
0..*
1
minimummaximumpreferred
StartOffset StartTime-Window-
Constraints
1
1
1
1..*{xor}
TimeWindow-Constraints
1
0..*
1
1