The Saratoga transfer protocol
work done with Surrey Satellite Technology Ltd

USS Saratoga, Bikini Atoll (Chris Jackson)

Saratoga is a fast file transfer protocol for hop-by-hop transfers on privately-owned networks - including the intermittently-connected networks used for delay-tolerant networking. Saratoga was first developed at Surrey Satellite Technology Ltd to download imagery from satellites.

Bundle Protocol from space demonstrated using Saratoga

Working with NASA Glenn Research Center, and using the ground-based testbed created for testing CLEO, the Cisco router in Low Earth Orbit, Saratoga has been developed further and written up as an internet-draft, aiming for experimental status. Saratoga is described in:

• Saratoga - fast file transfer from space, a short slideset describing the current status of the protocol (last updated May 2008).
• Saratoga: A Scalable File Transfer Protocol, Lloyd Wood, Wesley M. Eddy, Will Ivancic, Jim McKim and Chris Jackson, work in progress as an internet-draft, version -04 submitted to the IETF, October 2009.

Saratoga has developed over the past few years:

• Saratoga: a Delay-Tolerant Networking convergence layer with efficient link utilization, Lloyd Wood, Wesley M. Eddy, Will Ivancic, Jim McKim and Chris Jackson, Third International Workshop on Satellite and Space Communications (IWSSC '07), September 2007.
• Saratoga: a bundle convergence layer, Lloyd Wood, slideset presented at the IETF 69 DTNRG group meeting (audio recording from IETF 69 sessions), Chicago, July 2007.
• Saratoga: efficient transport over short-lived links, Wesley M. Eddy, slideset presented at the IETF 69 TSV area group meeting (audio recording from IETF 69 sessions), Chicago, July 2007.
• Introducing Saratoga, Lloyd Wood, slideset presented at the DTNRG workshop, Dublin, May 2007.

Saratoga can optionally also be used for Delay-Tolerant Networking (DTN) Bundle Protocol transfers. Using Saratoga, we are the first to demonstrate Bundle Protocol transfers from space, as noted on Slashdot and on Government Computer News.

• Experience with delay-tolerant networking from orbit, Will Ivancic, Wesley M. Eddy, Lloyd Wood, James Northam and Chris Jackson, submitted to the International Journal of Satellite Communications and Networking, special issue for best papers of ASMS 2008, for publication.
• CLEO Orbital Internet earns Time Magazine award, Robin Wolstenholme, Surrey Satellite Technology space blog, 14 November 2008.
• TIME's Best Inventions of 2008: #9 The Orbital Internet, Jeremy Caplan et al., Time Magazine, vol. 179 no. 19, 10 November 2008.
• Bits in space, Philip Baczewski, Network Connection, Benchmarks Online, University of North Texas, October 2008.
• Use of the Delay-Tolerant Networking Bundle Protocol from Space, Lloyd Wood, Will Ivancic, Wesley M. Eddy, Dave Stewart, James Northam, Chris Jackson and Alex da Silva Curiel, 59th International Astronautical Congress, Glasgow, 30 September 2008.
• Killer ap, In Orbit, Frank Morring, Jr. (ed.), Aviation Week and Space Technology, 29 September 2008, p. 18.
• Spaced-out Internet, Physics Buzz, Physics Central, 12 September 2008.
• UK-DMC satellite first to transfer sensor data from space using 'bundle' protocol, SSTL press release, 11 September 2008.
• Delay/Disruption-Tolerant Network Testing Using a LEO Satellite, Will Ivancic, Wesley M. Eddy, Lloyd Wood, Dave Stewart, Chris Jackson, James Northam and Alex da Silva Curiel, Eighth Annual NASA Earth Science Technology conference (ESTC 2008), University of Maryland, June 2008.
• Space-base DTN using a Commercially Available Low Earth Orbiting Satellite, Will Ivancic, slideset presented at the IETF 71 IRTF DTN research group meeting, March 2008 (audio recording from IETF 71 sessions).
• Using Saratoga with a Bundle Agent as a Convergence Layer for Delay-Tolerant Networking, Lloyd Wood, Wesley M. Eddy, Will Ivancic, Jim McKim and Chris Jackson, work in progress as an internet-draft, version -06 submitted to the IETF IRTF, October 2009.

Articles placing our bundle-in-space testing in context with later NASA deep-space bundle tests:

• Interplanetary Internet passes test, Alan Boyle, Cosmic Log, MSNBC, 19 November 2008.
• NASA stretches the internet 20 million miles, Matthew Sparkes, PC Pro, 19 November 2008.
• NASA testet Internet im All (in German), golem.de, 19 November 2008.

Development on Saratoga and resulting internet-drafts sprang from the collaboration involved in working with CLEO, the Cisco router in Low Earth Orbit.

Saratoga is named for the USS Saratoga, sunk near Bikini Atoll and now a popular diving site.

Related work
HTTP-DTN
HTTP-DTN is an alternative to bundling, that uses HTTP as a session layer hop-by-hop between nodes. HTTP is separated from TCP into its own layer, running over different convergence or transport layers.

• Turning HTTP into a standalone layer: decoupling HTTP from TCP, talk given to the TSVAREA meeting, IETF 75, Stockholm, 27 July 2009.
• Specifying transport mechanisms in Uniform Resource Indicators, Lloyd Wood, work in progress as an internet-draft, version -07 submitted to the IETF, October 2009.
• HTTP-DTN: delivery across ad-hoc networks, slideset presented at the IETF 71 IRTF DTN research group meeting, March 2008 (audio recording from IETF 71 sessions).
• Using HTTP for delivery in Delay/Disruption-Tolerant Networks, Lloyd Wood and Peter Holliday, work in progress as an internet-draft, version -04 submitted to the IETF IRTF, October 2009.

Bundle Protocol reliability
The bundle protocol lacks any notion of reliability, and ignores the well-known end-to-end principle. We have been attempting to address this, to increase reliability and performance in bundle networks:

• A Bundle of Problems, Lloyd Wood, Wesley M. Eddy and Peter Holliday, IEEE Aerospace conference, Big Sky, Montana, March 2009.
• Reliability: further points for discussion, Lloyd Wood, Wesley M. Eddy and Will Ivancic, slideset presented at the IETF 73 DTN research group meeting, November 2008.
• Reliability: points for discussion, Lloyd Wood, Wesley M. Eddy and Will Ivancic, slideset prepared for the IETF 71 IRTF DTN research group meeting, March 2008 (audio recording from IETF 71 sessions).
• Reliability-only Ciphersuites for the Bundle Protocol, Wesley M. Eddy, Lloyd Wood and Will Ivancic, work in progress as an internet-draft, version -06 submitted to the IETF IRTF, October 2009.
• Paths Towards Patching the Bundle Protocol's (Un)Reliability, Wesley M. Eddy, slideset presented at the IETF 69 DTNRG group meeting (audio recording from IETF 69 sessions), Chicago, July 2007.
• The DTN Bundle Protocol Payload Checksum Block, Wesley M. Eddy and Lloyd Wood, expired internet-draft, version -00 submitted to the IETF IRTF, July 2007.
• Checksum coverage and delivery of errored content, Lloyd Wood, Wesley M. Eddy, Jim McKim and Will Ivancic, work in progress, July 2007.