ONE Goals
• Provide single network interface regardless of physical link
• Provide reliable, isochronous message transport
Closed IONetClosed IONet
OpenInternet
Precipitation Processing System
Data
Workstation
Mission OperationsCenter
Data
Workstation
Data
MDP/CFDP
WSGTGN Router
WSGTGN Router
STGTGN Router
STGTGN Router
GuamGN Router
GuamGN Router
C&DH
IOO
PR-U MassStorageMass
Storage
GPM Spacecraft
GNC
95 kbps 95 kbps
PSE
1553
Ethernet
15 kbps
GMI
MDP/CFDPUDPCOP-1 like
One minute science data files
~ One minute insts HK files
~One minute
...
Instrument A
Instrument B
Instrument C
Instrument A
Instrument B
Instrument C
...
Instrument A
Instrument B
Instrument C
Instrument A
Instrument B
Instrument C
......
Instrument A
Instrument B
Instrument A
Instrument B
Instrument C
Instrument A
Instrument B
Instrument A
Instrument B
Instrument C
...
Instrument A
Instrument B
Instrument A
Instrument B
Instrument C
Instrument A
Instrument B
Instrument A
Instrument B
Instrument C
...
GPM Mission Data Flow Concept
1553GNC Components
25 kbps
PR-A
S/C HK files
BC
RT RT RT
BC
RT
RT
FileManager
FileXfer
Instr.Support
TlmOutput
NIC NIC
NIC
COMM
CmdIngest
SoftwareBus
NB
NIC
Prototype Goals
•Verify IP protocol use in real-time, flight environment• Maintain IP standard protocols• Use standard IP/Ethernet stacks – no modifications
• Implementation • minimize modifications to common executive services• maintain COP-1-like functionality• no isochrony
Prototype Effort Stack
PhysicalLayer
Data LinkLayer
NetworkLayer
Transport Layer
Application Layer
SOIFServicesApplications
UserApplications
Intra ProcessorCommunication
CommunicationServices
Transport API Messaging API File Transfer API Data Link API
SOIF NetworkManagement
Ethernet
Device Driver
IP Stack
UDP
Network Bus
Comm User Apps
Flight Software Architecture
PSE
Inter-task Message Router (SW Bus)
MemoryChecksum
EDACMemoryScrubber
Tlm &StatisticsMonitor
1 HzTime Synch
MDP/CFDP
ACSHK Data
AcquisitionManager
PSESupport
Health &Safety
Manager
SoftwareManager
TimeCode
StoredCommandProcessor
TelemetryOutput
FileManager
TransponderCmd (UDP COP-1)
Thruster InstrumentsACS
Components
AutonomousNavigation
SpacecraftAnalogs
PowerSupply
Electronics
Switch Commands & Readbacks
Commands
Common Executive
C&DH
CommandIngest
MemoryDwell
Real-time Telemetry (UDP)
Fire Cmd
ThrusterStatus Data
COMM(UL/DL I/F)
Sensor Data,Time
GNC
Actuator Cmd
InstrumentsSupport
Science,Housekeeping
Date
MassStorage
1553 BusSupport
Science & HK files (MDP/CFDP)
HGA
HGA CmdPosition
Network Support
NB
SpaceWireSupport
GSFC Protoype Effort - Commanding
• characteristics of commanding that need to be addressed for a complete IP/command implementation: acknowledgment, sequencing, and reliability
• Implement many of the COP-1 features including sequence verification, retransmit, bypass,
and lock-out • COP-1 functions are performed at the user application layer in the Command Ingest Task • CLCW will be used for verification and is downlinked by CI in a UDP packet, on a
separate UDP port • On the uplink side, the secondary header of the CCSDS command includes a sequence counter,
the unlock bit, and the bypass bit
GSFC Protoype Effort – Special Commanding
•There are 2 types of special commands:
• COM special command:• is distributed via hardwire•.defined by a specific, pre-determined UDP destination port• action of the COM special command is defined in the UDP data• The UDP data will either be formatted as a byte(s) or a CCSDS packet (TBD), but must be at a fixed offset from the IP header.
• Bus special command:• broadcast over the network• defined by the host id of the IP address equaling a value of 25• memory controller on the NIC will look at the UDP destination port to determine if the command is for its subsystem• If the command is valid, it will be executed by subsystem hardwares as defined in the UDP data• UDP command data must be at a fixed offset from the IP header
Dest Src CRCEthernet Frame(RFC 894)
IPPacket
VersionHdr lenTOS
TTL,Proto
SourceIP
DestIP
UDP PacketTotal Length,ID,Flags, Frag Offset
Type IP Hdr UDP Hdr Data(0800) (Command)
2 6 2 4 4
246-1500
266
HdrCksum
2
Source PortNumber
Destination Port Number
UDP Length
UDPChecksum
2 2 2 18-14722
UDPPacket
Data(Command)
IP Command Format
26-1480
PACKET ID
TYPE
3 111
VERID
SECHDRFLAG
APP ID
1
SEQFLAGS
SEQCNT
2 14
PACKET SEQCONTROL
PKTLEN
16
SECONDARY HEADER DATA
CMDSEQ
COUNT
CCSDS Command Format
8
By-pass
ControlCmd Flg
=01
Flags
5
spare
Secondary header bit 0 = 0 for non-CCSDS-defined header .
1
6 byte primary header 2 byte sec. header
GSE
Ethernet/IP Multi-node Testbed
C&DH
I/F
IP/TCP/UDP
561 NIC
SFDUs
GOAL: Add subsystem simulators
CONFIGURATION:Addition of PSE & GNC SimulatorsAddition of 561 Switch
NB
SB
TO
ASIST
Stack
GSFC561 Driver
MEDIACONVERTER
SWITCH
PSE Simulator
IP/TCP/UDPIP/UDP
IP/UDP
MEDIACONVERTER
MEDIACONVERTER
GNCSimulator
CI