FPGA/ASIC Cores for Interplanetary Internet Applications

1. FPGA/ASIC Cores for Interplanetary Internet Applications Yosef Gavriel Tirat-Gefen, PhD Senior Member IEEE Member of ACM, Internet Society (IPNSIG) Affiliations: Staff Fellow at the Center for Devices and Radiological Health (CDRH) / FDA, Rockville, MD Applied Physics Graduate Program Dept. Physics and Astronomy George Mason University, Fairfax, VA yosefgavriel@computer.org

2. Presentation Overview Motivation The interplanetary internet (IPN) Bundle based protocols CCSDS protocols Adapting CCSDS Protocols for IPN Work Plan Current results Conclusion

3. Motivation Very long delay Mars / Asteroid Repeater Enabling extremely long delay/intermittent communication

4. Motivation Link to Earth – very long delay Repeater Short distance communication links Supporting Manned or Robotic Missions

5. Additional Applications Delay Dependent Networks Sensor Networks Military Tactical Networks National Emergency Communication Infrastructure 24/7 Health Monitoring of Remotely Located Patients Mobile Medical Networks

6. Layer 3 Layer 2 Layer 1 Layer 3 Layer 2 Layer 1 Traditional TCP/IP Networking Application/O.S. TCP Layer 3 (IP) Layer 2 (MAC) Layer 1 (PHY) Application/O.S. TCP Layer 3 (IP) Layer 2 (MAC) Layer 1 (PHY) Router

7. Limitations of TCP/IP Networking • Performance breaks down for links with long delays or intermittent communication. • Timeout limitations. • Memory requirements are huge for long delay round trips. • Routing algorithms (e.g. BGP) are based in TCP. Routing would use almost all bandwidth available in an interplanetary link. • Not suitable for asymmetric communication links, e.g. telemetry/command. • Not designed for links with high bit error rates (BER).

8. The Interplanetary Internet (IPN) • Interplanetary Internet Special Interest Group (www.ipnsig.org) established in September 1999. • Goal is to develop networking standards for deployment in deep space missions, e.g.: • To allow sharing of resources among different missions. • To establish satellite repeaters to support a future manned mission to Mars. • Part of research effort in delay dependent networking (DTN).

9. IPN Key Technologies • Interplanetary Gateways. • Interplanetary Backbone. • Security • Power aware networking (e.g. routing algorithms) • Coding techniques for error detection and recovery • CCSDS protocols evolved for interplanetary deployment

10. Layer 3 Layer 2 Layer 1 Layer 3 Layer 2 Layer 1 Bundle Protocols Application/O.S. Bundle Transport Layer 3 (Network) Layer 2 (MAC) Layer 1 (PHY) Application/O.S. Bundle Transport Layer 3 (Network) Layer 2 (MAC) Layer 1 (PHY) Bundle Transport Transport

11. Key features in Bundle Networking • Applications send and receive bundles instead of transport streams. • Creates an illusion of an end-to-end connection. Support of intermittent links. • Custody of data is passed along intermediary nodes in the path between source and destination. • Source does not need to wait for a ACK from destination to release buffer space. • Security is also enforced by the bundle layer. • IPN addressing is divided in regions. Each region is a standard internet. Bundles are exchanged in region gateways.

12. CCSDS Protocols • Consultative Committee for Space Data Systems - CCSDS • Suite of protocols for space missions and satellites applications • Standards for telemetry (TM) and telecommand (TC). • Deployed by more than 155 missions so far. • File Transfer Delivery Protocol (CDFP) is becoming the baseline for IPN development. • CCSDS standards for link layer and data coding can be evolved for interplanetary deployment.

13. CCSDS protocol layers Running on a CPU Application Layer SCPS-FP (File transfer) SCPS-TP (Transport) SCPS-SP (Security) SCPS-NP (Network) TM – Data Link TC - Data Link TM-Coding TC-Coding RF and Modulation (PHY) Suitable for software implementation Suitable for FPGA/ASIC and off-the-shelf PHY chips

14. FPGA/ASIC Cores for IPN • Coding layer = Channel Coding and Synchronization • Link Layer = Space Data Link Protocol • Coding and link layer standards are suitable for FPGA/ASIC implementation. • Advantages in Low Power consumption and performance. • Safety and correctness are essential as these cores may deployed in manned missions. • These cores should be able to use radiation hard non-volatile memory in addition to RAM banks.

15. Our Work • A library of major building blocks for the link and coding layers for use by designers of future IPN hardware. • Capturing relevant protocols for these layers in SDL – A Formal Object-oriented Language for Communicating Systems. • The library contains modules coded in: • Synthesizable – C (e.g. Handel-C) • Synthesizable and Behavioral VHDL. An open source IP-core library!

16. Proposed Architecture SCPS-NP (Network) Interface IP/Firmware module TM/TC multiplexing Rx Memory controller Tx Memory controller TM/TC Link Cores Coding Layer Blocks Tx Memory Bank (RAM + Non-volatile) Rx Memory Bank (RAM + Non-volatile) PHY

17. Data Link Core – Tx Direction From Network Layer Interface (SCPS-NP) Virtual Channel Multiplexer Master Channel Generation Master Channel Multiplexer To coding blocks (e.g. Turbo-coding/BCH)

18. Data Link Core – Rx Direction To Network Layer Interface (SCPS-NP) Virtual Channel Demultiplexer Master Channel Reception Master Channel Demultiplexer From decoding blocks

19. Present Status Our target devices are Virtex and Actel (Radiation Hard) FPGAs for now. Plan to include other FPGA families later. Cores are suitable for low-power applications. Full implementation of Link and Coding layers will demand more than one device for current FPGA technology.

20. Conclusion The availability of a library of cores for the future interplanetary internet, supporting its lower protocol layers, may speed up its deployment. These same cores could be adapted to earth for delay dependent networks (e.g., sensor networks with intermittent links, mobile medical networks).