07 September 2015 Peter Mendham SOIS Plug-and-Play: Use Cases and Requirements

2 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Agenda Introduction and background Operational scenarios Scenario use cases Synthesising a use case Service level approaches and requirements Subnetwork level requirements Subnetwork support requirements Recommendations Comments to encourage discussion

3 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Introduction Asked to review plug-and-play… Use cases Definition Scope Requirements Starting point was the concept paper Plus any other published material available

4 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Approach Back to basics Largely ignore the SOIS architecture Intend to review the architecture as an outcome Scenarios to use cases to requirements to a better defined purpose and scope

5 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Definitions of Plug-and-Play Generic definition (various sources) SOIS definition (concept paper) Plug-and-play encompasses the characteristics of an interface or device specification to facilitate the discovery of a hardware component in the system and the automatic configuration of that component such that it may be used without user intervention. Plug-and-play encompasses the mechanisms necessary to establish communication services between two data systems in a spacecraft’s onboard (sub-)network, without requiring reconfiguration or manual installation of device drivers by any user (higher-level service or OBSW application).

6 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Scenarios Rapid spacecraft development Automated integration and test FDIR assistance Ground segment access

7 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Rapid Spacecraft Development (1) Many drivers to reduce spacecraft development time Commercial drivers: < 2 years Military drivers (e.g. ORS): < 1 week Reduce development time through Standardised components Standardised interfaces Incremental qualification/V&V (cf. IMA) Use of in-house/commercial off the shelf Rapid integration

8 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Rapid Spacecraft Development (2) Plug-and-play enablers: Removal of dependence on subnetwork configuration Reuse of applications independently from devices Reuse of devices independently from applications Increase portability of applications Beneficiaries: System integrators (e.g. primes) Customers (e.g. agencies) Device manufacturers Permits/promotes inter-agency cooperation

9 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Automated Integration and Test (1) During integration a number of configurations are necessary for: Spacecraft EGSE Each configuration must be validated Use plug-and-play to permit Discovery of devices Automated configuration of services/applications Automated configuration of EGSE and other test equipment

10 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Automated Integration and Test (2) Plug-and-play enablers: Removal of dependence on subnetwork configuration Configuration of communications independent to applications Validate applications independent to communications Validate devices independently from applications etc. Beneficiaries: System integrators (e.g. primes) Customers (e.g. agencies) Device and EGSE manufacturers Permits/promotes inter-agency cooperation

11 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements FDIR Assistance (1) Fault detection Detect the disappearance of subnetwork devices Might indicate a fault Isolation Use subnetwork features to isolate device Reconfigure routing/fail over bus Recovery Identify replacement device(s) Reconfigure subnetwork as necessary

12 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements FDIR Assistance (2) Plug-and-play enablers: Device discovery (addition/removal notification) Device isolation (depending on subnetwork) Transparent subnetwork reconfiguration for identical redundant devices Beneficiaries: Software developers System integrators (e.g. primes) Customers (e.g. agencies) Spacecraft operators (may see more reliable spacecraft)

13 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Ground Segment Access (1) Automated adaptation of ground segment interface to accommodate Different spacecraft configurations Different devices Adapt telemetry expected Format and content Adapt telecommands issued Types available and format

14 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Ground Segment Access (2) Plug-and-play enablers: Device discovery Provide services independently from subnetwork configuration Service discovery by ground segment applications Beneficiaries: Operational stakeholders Original space and ground segment customer(s) (e.g. agencies) System integrators (e.g. primes) Space and ground segment developers

15 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Use Cases Use case for each scenario Presented as a process Or multiple processes Will eventually be drawn together into a synthesised use case

16 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Rapid Spacecraft Development Use Case (1) Use case for iterative/incremental development and qualification/V&V Use case for integration of devices into spacecraft Device driven process for subnetwork issues Application driven process for service issues

17 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Rapid Spacecraft Development Use Case (2) 1.Device is physically and logically integrated onto spacecraft network 2.Subnetwork plug-and-play features discover the device 3.Subnetwork plug-and-play network management carries out network configuration and configuration of subnetwork-related device features 4.Subnetwork plug-and-play network management carries out configuration of subnetwork services 5.Subnetwork plug-and-play assists in the discovery of services/capabilities of device 6.Capabilities are exposed through to (potentially standardised) applications via a suitably standardised interface

18 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Rapid Spacecraft Development Use Case (3) 1.The application is loaded 2.The application queries the service interface for the availability of a specific device or device type 3.If the device is available the application obtains the service interface and binds to it, application features relating to the service are then enabled 4.If the device is not available the application either waits and then returns to step 2 (re-query), or disables the features relating to the service

19 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Automated Integration and Test Use Case (1) Many similarities to previous scenario Two parts: Plug-and-play on spacecraft to adapt to integrated devices Plug-and-play of EGSE attached to spacecraft for integration and test

20 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Automated Integration and Test Use Case (2) 1.Device is physically and logically integrated onto spacecraft network 2.Subnetwork plug-and-play features discover the device 3.Subnetwork plug-and-play network management carries out network configuration and configuration of subnetwork-related device features 4.Subnetwork plug-and-play network management carries out configuration of subnetwork services 5.Subnetwork plug-and-play assists in the discovery of services/capabilities of device 6.Capabilities are exposed through to (potentially standardised) applications via a suitably standardised interface 7.Applications registered to use the available service interfaces are either loaded or have the appropriate service-related functions enabled (if they are already loaded)

21 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Automated Integration and Test Use Case (3) 1.EGSE is physically and logically integrated onto spacecraft network 2.EGSE subnetwork plug-and-play features discover the device 3.Subnetwork plug-and-play network management detects current network configuration and configuration of subnetwork-related device features and configures EGSE subnetwork services accordingly 4.Subnetwork plug-and-play assists in the discovery of services/capabilities of device 5.Capabilities are exposed through to (potentially standardised) EGSE applications via a suitably standardised interface 6.Test and/or V&V applications registered to use the available device service interfaces are either loaded or have the appropriate service- related functions enabled (if they are already loaded)

22 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements FDIR Assistance Use Case (1) FDIR process utilises plug-and-play at four stages: Initial integration Fault detection Fault Isolation Recovery Additionally, plug-and-play may be used to accommodate non-duplicate redundancy Such as 3 of 4 arrangements e.g. tetrahedral gyro arrangements

23 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements FDIR Assistance Use Case (2) Initial Integration Subnetwork plug-and-play features discover both prime and redundant devices Subnetwork plug-and-play network management carries out network configuration and configuration of subnetwork-related device features Subnetwork plug-and-play network management carries out configuration of subnetwork services; Subnetwork plug-and-play assists in the discovery of services/capabilities of device Capabilities of both devices are exposed through to (potentially standardised) applications via a suitably standardised interface

24 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements FDIR Assistance Use Case (3) Fault Detection 1.The prime device ceases to be either physically or logically present on the subnetwork 2.Network discovery determines the absence of the device either through active polling or passive notification 3.Optionally, applications are notified of the absence of the device (and potential failure) and/or the lack of availability of particular services

25 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements FDIR Assistance Use Case (4) Fault Isolation 1.Subnetwork plug-and-play network management reconfigures the subnetwork to isolate the failed prime device (if possible)

26 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements FDIR Assistance Use Case (5) Recovery 1.Subnetwork plug-and-play network management carries out network configuration and configuration of subnetwork-related device features for the redundant device 2.Subnetwork plug-and-play network management carries out configuration of subnetwork services to accommodate the redundant device

27 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements FDIR Assistance Use Case (6) Service Level Adaptation 1.Subnetwork plug-and-play assists in the discovery of services/capabilities of the remaining device(s) 2.A uniform service interface is presented to a (potentially standardised) application though synthesis of the services provided by the available devices 3.Applications query the service interface to determine the availability of replacement services for the ones lost 4.If suitable services are available the application obtains the service interface and binds to it, application features relating to the service are then enabled (this may require adapting the service interface e.g. type conversions, frame rotations) 5.If suitable services are not available the application either waits and then returns to step 2 (re-query), or disables the features relating to the services

28 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Ground Segment Access Use Case (1) Splits into two parts Onboard integration and discovery of devices Access by ground segment applications First part is the same as before Process of second part depends access Device oriented Service oriented

29 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Ground Segment Access Use Case (2) Device Oriented 1.The ground segment application queries the spacecraft service interface for the availability of a specific device or device type 2.If the device is available the application obtains the service interface and binds to it, application features relating to the service are then enabled 3.If the device is not available the application either waits and then returns to step 2 (re-query), or disables the features relating to the service

30 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Ground Segment Access Use Case (3) Service Oriented Ground segment applications query the service interface to the spacecraft to determine the availability of suitable services If suitable services are available the application obtains the service interface and binds to it, application features relating to the service are then enabled (this may require adapting the service interface e.g. type conversions) If suitable services are not available the application either waits and then returns to step 2 (re-query), or disables the features relating to the services

31 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Synthesising a Use Case Separate levels Subnetwork level Service level (device capabilities) Subnetwork level is relatively easy Service level splits into three approaches Device-driven, device-bound Application-driven, device-bound Application-driven, service-bound

32 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Subnetwork Level Synthesised Use Case 1.A change is made to the devices physically and/or logically integrated onto spacecraft subnetwork 2.Subnetwork plug-and-play features discover the addition or removal of a devices 3.Subnetwork plug-and-play network management carries out network configuration and configuration of subnetwork-related device features 4.Subnetwork plug-and-play network management carries out configuration of subnetwork services 5.Subnetwork plug-and-play assists in the discovery of services/capabilities of device

33 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Device-Driven, Device-Bound Use Case 1.The subnetwork indicates the availability of a device or device class, potentially via a higher level service 2.Applications registered to use the available device service interfaces are either loaded or have the appropriate service-related functions enabled (if they are already loaded), or are simply informed

34 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Application-Driven, Device Bound Use Case 1.The application queries the service interface for the availability of a specific device or device type 2.If the device is available the application obtains the service interface and binds to it, application features relating to the service are then enabled 3.If the device is not available the application either waits and then returns to step 1 (re- query), or disables the features relating to the service

35 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Application-Driven, Service-Bound 1.Applications query the service interface to determine the availability of suitable services on the basis of the service elements they provide; 2.If suitable services are available the application obtains the service interface and binds to it, application features relating to the service are then enabled (this may require adapting the service interface e.g. type conversions) 3.If suitable services are not available the application either waits and then returns to step 1 (re-query), or disables the features relating to the services

36 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Where Does the Device Interface Come From? Something has to know how to talk to the device (i.e. a device driver) Independent concern to how interface is exposed Interface can be: Manually written or auto-coded Generated online or offline Making use of an electronic data sheet

37 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Manually Generated Device Interface EDS Manual Coding Load/EnableInstantiated I/F VID/PID Class ID Instance ID Subnetwork Device Application Device I/F OBC Ontology

38 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Auto-Coded Device Interface EDS Auto-coding Load/EnableInstantiated I/F VID/PID Class ID Instance ID Subnetwork Device Application Device I/F OBC Primitive Ops Ontology Manual Coding

39 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Online Generated Device Interface EDS GenerationGenerated I/F VID/PID Class ID Instance ID Subnetwork Device Application OBC Primitive Ops Ontology Manual Coding

40 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Device Interface Generation Comments Similarities All can/must use an EDS All utilise subnetwork level plug-and-play Importantly All are completely independent of subnetwork Except for EDS provision All are completely independent of service interface approach

41 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Service Level Requirements Need device enumeration Need service virtualisation Service interface depends on approach Virtual device classes with standardised interfaces Could permit device-driven application loading/enabling Service interface permitting queries on service elements e.g. “I need a service which gives me the temperature of this part of the spacecraft”

42 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Subnetwork Level Requirements Device discovery Management of subnetwork Subnetwork-specific features of devices Subnetwork resources Management of subnetwork addressing Reconfiguration of other subnetwork services appropriately

43 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Subnetwork Requirements Network discovery Device discovery (polled/notified) Topology discovery Device identification Unique identification Type/class Configuration of subnetwork-specific device features e.g. address, link speed Configuration of subnetwork resources e.g. bus controllers, routers Sourcing of electronic data sheet

44 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Subnetwork Network Management Issues of mechanism How addresses are set Subnetwork specific Independent of mission Issues of policy How addresses should be assigned Subnetwork specific Mission or mission class specific Mechanism and Policy should be separated

45 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Subnetwork Plug-and-Play Architecture Applications Physical Layer Device Enumeration Service Device Virtualisation Service Device Access Service Device Discovery Service Memory Access Service Packet Service Network Management Service

46 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Subnetwork Plug-and-Play Architecture Applications Physical Layer Device Enumeration Service Device Virtualisation Service Device Access Service Device Discovery Service Memory Access Service Packet Service Network Management Service Configuration Network Management Service Policy Defined Interface?

47 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Plug-and-Play Scope Subnetwork and service levels are separable Subnetwork level scope: Device discovery Device identification Subnetwork configuration and management Service level scope: Service discovery Standardised virtual interface Query-able interface? Application binding

48 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Conclusions and Discussion Points (1) Plug-and-play is highly beneficial It would seriously hinder the progress of platforms using SOIS not to have plug-and-play Requirements for subnetwork level are easily understood Requirements placed on subnetwork technologies are easily understood Scope of plug-and-play in the subnetwork context is easily definable and constrained A couple of minor changes necessary to subnetwork architecture Policy should be separated from mechanism Subnetwork is separable from service level

49 CCSDS Fall Meeting: SOIS PnP Use Cases and Requirements Conclusions and Discussion Points (2) A standard format for electronic data sheets would be useful to help tie subnetwork and service levels Service level plug-and-play is less constrained Different approaches possible Based on standardised device classes known a priori Based on a query-able service interface to permit service inspection Should both be supported? Should subnetwork and service level plug-and-play be separated in the context of SOIS?