The Interplanetary Overlay Networking Protocol Accelerator (IONAC) described previously in “The Interplanetary Overlay Networking Protocol Accelerator” (NPO-45584), NASA Tech Briefs, Vol. 32, No. 10, (October 2008) p. 106 ( provides functions that implement the Delay Tolerant Networking (DTN) bundle protocol. New missions that require high-speed downlink-only use of DTN can now be accommodated by the unidirectional IONAC-Lite to support high data rate downlink mission applications. Due to constrained energy resources, a conventional software implementation of the DTN protocol can provide only limited throughput for any given reasonable energy consumption rate. The IONAC-Lite DTN Protocol Accelerator is able to reduce this energy consumption by an order of magnitude and increase the throughput capability by two orders of magnitude. In addition, a conventional DTN implementation requires a bundle database with a considerable storage requirement. In very high downlink data-rate missions such as near-Earth radar science missions, the storage space utilization needs to be maximized for science data and minimized for communications protocol-related storage needs.

The IONAC-Lite DTN Protocol Accelerator is implemented in a reconfigurable hardware device to accomplish exactly what’s needed for high-throughput DTN downlink-only scenarios.

The following are salient features of the IONAC-Lite implementation:

  • An implementation of the Bundle Protocol for an environment that requires a very high rate bundle egress data rate. The C&DH (command and data handling) subsystem is also expected to be very constrained so the interaction with the C&DH processor and the temporary storage are minimized.
  • Fully pipelined design so that bundle processing database is not required.
  • Implements a lookup table-based approach to eliminate multi-pass processing requirement imposed by the Bundle Protocol header’s length field structure and the SDNV (self-delimiting numeric value) data field formatting.
  • 8-bit parallel datapath to support high data-rate missions.
  • educed resource utilization implementation for missions that do not require custody transfer features. There was no known implementation of the DTN protocol in a field programmable gate array (FPGA) device prior to the current implementation.

The combination of energy and performance optimization that embodies this design makes the work novel.

This work was done by Jordan L. Torgerson, Loren P. Clare, and Jackson Pang of Caltech for NASA’s Jet Propulsion Laboratory. For more information, contact the JPL Innovative Technology Assets Management Office, 1-818-393-3421, and reference NPO-47344.

NASA Tech Briefs Magazine

This article first appeared in the August, 2011 issue of NASA Tech Briefs Magazine.

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