CCSDS Fall Meeting at ESTEC JAXA’s DTN activity Kiyohisa Suzuki JAXA October 2009, CCSDS Fall Meeting at ESTEC

CCSDS Fall Meeting at ESTEC Contents Computer Simulation for DTN network Feasibility study for NASA-JAXA DTN Experiments on ISS October 2009, CCSDS Fall Meeting at ESTEC

Computer Simulation for DTN network Purpose To learn and accumulate the knowledge of DTN specification and function toward future spacecraft communication. To carry out a feasibility study on the capability for End-to-End spacecraft communication network which implemented DTN node. October 2009, CCSDS Fall Meeting at ESTEC

Computer Simulation for DTN network Simulation tools & Scenario Simulation Tools (full software and using COTS) OPNET To implement protocols To create network topology To calculate AOS/LOS judgment in each tracking station. STK To calculate satellite orbit Simulation Scenario LEO satellite network (DTE) DTN Gateway Node on LEO satellite, Operation Center,each tracking station. Probability oscillation for loss of frames or packets To calculate transmission time, loss of frames , number of retransmission ,etc Static IP routing Network Operation center decides destination of grand station by FD data October 2009, CCSDS Fall Meeting at ESTEC

Computer Simulation for DTN network Building simulation model Implemented DTN BP (with custody transfer) UDP IP CCSDS encapsulation CCSDS COP-1 CCSDS TC/AOS RF bandwidth Not Implemented DTN Convergence Layer Bundle security CCSDS Space link channel coding RF character (modulation, polarization etc) Specifications Bundle Protocol Specification RFC5050 User Datagram Protocol RFC768 Internet Protocol RFC791 Encapsulation service CCSDS 133.1-B-1 TC Space Link Protocol CCSDS 232.0-B-1 AOS Space Link Protocol * CCSDS 732.0-B-2 Communications Operation Procedure-1 CCSDS 232.1-B-1 * Only for Downlink October 2009, CCSDS Fall Meeting at ESTEC

CCSDS Fall Meeting at ESTEC Computer Simulation for DTN network Samples of simulation node model Spacecraft Onboard design Node design “DTN Client Node” October 2009, CCSDS Fall Meeting at ESTEC “DTN Gateway Node”

Computer Simulation for DTN network Findings DTN on LEO satellite network has the high certainty for data transfer in the aspect of QOS. To apply DTN technology to satellite communication, DTN BP specification(RFC 5050) and/or specifications of peripheral technology will need additional specs. Routing algorithm The flow control of different bandwidth between ground internet and RF link DTN needs to be considered assignment between DTN BP and lower layer’s identification. Because Space Link Protocol can define the services each VC. JAXA did not implemented DTN convergence Layer in current simulation’s stack. We believe some issues are solved by DTN CL. October 2009, CCSDS Fall Meeting at ESTEC

CCSDS Fall Meeting at ESTEC Computer Simulation for DTN network Custody DIS (UDP/IP over CCSDS) Loss Rate [%] Delivery Rate [%] Overlap Bundle Count Dest. Not Revieved Bundle Count Frame 0.0 *1 100.0 Frame 0.003 *1 Frame 0.3 *1 Packet 0.1 *2 99.7 43 Custody has the high certainty for data transfer in the aspect of QOS. Destination DTN node received same context of BP (overlapped) caused by retransmission. Custody ENA Loss Rate [%] Delivery Rate [%] Overlap Bundle Count Dest. Not Revieved Bundle packet Count Frame 0.0 *1 100.0 Frame 0.003 *1 Frame 0.3 *1 2 Packet 0.1 *2 18 *1 Frame loss between satellite and ground station *2 IP packet loss in internet cloud at ground October 2009, CCSDS Fall Meeting at ESTEC

Computer Simulation for DTN network Flow Control Routing Simulation results indicated to arise congestion and many retransmitting. Retransmit Frame Loss “RFC5050”did not define routing algorithm October 2009, CCSDS Fall Meeting at ESTEC

Computer Simulation for DTN network Sample of BP behavior with Custody transfer (Uplink) Routing issues BP sent after one revolution October 2009, CCSDS Fall Meeting at ESTEC

Feasibility study for NASA-JAXA DTN Experiments on ISS JAXA started the feasibility study for DTN experiments on ISS – DRTS(Data Relay Test Satellite) with NASA. Firstly, feasibility study focused as follows; Connectivity discussion about considered route. ISS programmatic things JAXA conducted technical meetings Aug. 2009 with NASA. JAXA continues internal technical and administrative coordination. October 2009, CCSDS Fall Meeting at ESTEC

CCSDS Fall Meeting at ESTEC Fin October 2009, CCSDS Fall Meeting at ESTEC

CCSDS Fall Meeting at ESTEC Typical Parameters October 2009, CCSDS Fall Meeting at ESTEC

CCSDS Fall Meeting at ESTEC Computer Simulation for DTN network BP behavior with Custody transfer (downlink) October 2009, CCSDS Fall Meeting at ESTEC

CCSDS Fall Meeting at ESTEC Computer Simulation for DTN network Samples of State transition diagram in protocol view DTN BP CCSDS COP-1 CCSDS AOS October 2009, CCSDS Fall Meeting at ESTEC