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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 [email protected] 2005 MAPLD/1006 1 Tirat-Gefen Presentation Overview • Motivation • The interplanetary internet (IPN) • Bundle based protocols • CCSDS protocols • Adapting CCSDS Protocols for IPN • Work Plan • Current results • Conclusion 2005 MAPLD/1006 2 Tirat-Gefen Motivation Very long delay Mars / Asteroid Repeater Enabling extremely long delay/intermittent communication 2005 MAPLD/1006 3 Tirat-Gefen Motivation Link to Earth – very long delay Repeater Short distance communication links Supporting Manned or Robotic Missions 2005 MAPLD/1006 4 Tirat-Gefen 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 2005 MAPLD/1006 5 Tirat-Gefen Traditional TCP/IP Networking Application/O.S. Application/O.S. TCP TCP Layer 3 (IP) Layer 2 (MAC) Layer 1 (PHY) 2005 MAPLD/1006 Router Layer 3 (IP) Layer 3 Layer 3 Layer 2 (MAC) Layer 2 Layer 2 Layer 1 (PHY) Layer 1 Layer 1 6 Tirat-Gefen 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). 2005 MAPLD/1006 7 Tirat-Gefen 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). 2005 MAPLD/1006 8 Tirat-Gefen 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 2005 MAPLD/1006 9 Tirat-Gefen Bundle Protocols Application/O.S. Application/O.S. Transport Layer 3 (Network) Layer 2 (MAC) Layer 1 (PHY) 2005 MAPLD/1006 Bundle Bundle Bundle Transport Transport Transport Layer 3 Layer 3 Layer 3 (Network) Layer 2 Layer 2 Layer 2 (MAC) Layer 1 Layer 1 Layer 1 (PHY) 10 Tirat-Gefen 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. 2005 MAPLD/1006 11 Tirat-Gefen 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. 2005 MAPLD/1006 12 Tirat-Gefen CCSDS protocol layers Running on a CPU 2005 MAPLD/1006 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) 13 Suitable for software implementation Suitable for FPGA/ASIC and off-theshelf PHY chips Tirat-Gefen 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. 2005 MAPLD/1006 14 Tirat-Gefen 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. 2005 MAPLD/1006 15 An open source IP-core library! Tirat-Gefen Proposed Architecture SCPS-NP (Network) Interface IP/Firmware module TM/TC multiplexing Rx Memory controller Rx Memory Bank (RAM + Non-volatile) TM/TC Link Cores Coding Layer Blocks Tx Memory controller Tx Memory Bank (RAM + Non-volatile) PHY 2005 MAPLD/1006 16 Tirat-Gefen 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) 2005 MAPLD/1006 17 Tirat-Gefen Data Link Core – Rx Direction To Network Layer Interface (SCPS-NP) Virtual Channel Demultiplexer Master Channel Reception Master Channel Demultiplexer From decoding blocks 2005 MAPLD/1006 18 Tirat-Gefen 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. 2005 MAPLD/1006 19 Tirat-Gefen 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). 2005 MAPLD/1006 20 Tirat-Gefen