1. 12006 MAPLD International ConferenceSpaceWire 101 Seminar CCSDS Standard On-Board InterfaceS (SOIS) Rick Schnurr NASA – Goddard Space Flight Center CCSDS – SOIS Sub-Network working group chair 2006 MAPLD International Conference Washington, D.C. September 25, 2006

2. 22006 MAPLD International ConferenceSpaceWire 101 Seminar CCSDS-SOIS Goal To develop standards that will: –Improve: Process of spacecraft development and integration Quality of the finished product –Facilitate adoption of new technologies Hardware & software Support international onboard interface interoperability.

3. 32006 MAPLD International ConferenceSpaceWire 101 Seminar SOIS - Approach To standardise interfaces between items of spacecraft equipment by: –Specifying well-defined standard service interfaces and protocols Allow standardized access to sensors, actuators and generic spacecraft functions –Spacecraft applications to be developed independently of the mechanisms that provide these services. Applications are insulated from the specifics of a particular spacecraft implementation –may be reused across different spacecraft platforms with little regard of implementation details

4. 42006 MAPLD International ConferenceSpaceWire 101 Seminar SOIS - Architecture

5. 52006 MAPLD International ConferenceSpaceWire 101 Seminar SOIS Sub-Network Architecture SOIS Sub-Network defines abstract service interface –Abstract because it is not Bus/LAN specific. Mapping describes how services are implemented on a specific bus Maps Sub-Network services onto a Data-Link using Sub-Network Convertence functions or Data Link specific functions.

6. 62006 MAPLD International ConferenceSpaceWire 101 Seminar Sub-Network Architecture Packet Transfer Service Get/Set Parameter Service Memory Read/Write Service Time Distribution Service Device Discovery Service Test Service Services : Sub Network Bus Mapping Sub-Network Convergence functions Protocol Multiplex Priority Address Translation PDU encapsulation Resource Reservation Fragmentation Retry Link Redundancy SpaceWireMIL-STD- 1553 IEEE-1394CANEthernet Others – USB, IEEE-802.11, One Wire Standard Data Links PNP Support SOIS - Subnetwork

7. 72006 MAPLD International ConferenceSpaceWire 101 Seminar SOIS Sub-Network Architecture SpaceWire already supports most mapping functions defined. –In many cases more than one mapping function exits for each block Example, GAP vs RMAP Mapping from SOIS services is a priority of the CCSDS-SOIS sub-network working group

8. 82006 MAPLD International ConferenceSpaceWire 101 Seminar SOIS support for CCSDS SOIS Mapping Protocol Mux – SpaceWire Standard Fragmentation – Not needed Reliability – GOES reliability protocol GET/SET and Memory Read – GAP or RMAP PNP – some work in progress could be deferred Address translation – needed Priority – needed Resource reservation - needed

9. 92006 MAPLD International ConferenceSpaceWire 101 Seminar Conclusion CCSDS SOIS Sub-network services and required mapping functions are well defined at this point. Packet service and quality of service model are also mostly complete Mapping SpaceWire to CCSDS SOIS is a logical next step. Input from the SpaceWire community is desired.