Delay/disruption-tolerant network testing using a LEO satellite

Proceedings of the IEEE, 2000

Applications of DTN for future satellite networks are discussed in this paper, as well as the relationship between DTN and quality of service (QoS).

2010

The Disaster Monitoring Constellation (DMC), constructed by Surrey Satellite Technology Ltd (SSTL), is a multi-satellite Earth-imaging low-Earth-orbit sensor network where captured image swaths are stored onboard each satellite and later downloaded from the satellite payloads to a ground station. Store-andforward of images with capture and later download gives each satellite the characteristics of a node in a Delay/Disruption Tolerant Network (DTN). Originally developed for the 'Interplanetary Internet', DTNs are now under investigation in an Internet Research Task Force (IRTF) DTN research group (RG), which has developed a 'bundle' architecture and protocol. The DMC is currently unique in its adoption of the Internet Protocol (IP) for its imaging payloads and for satellite command and control, based around reuse of commercial networking and link protocols. These satellites' use of IP has enabled earlier experiments with the Cisco router in Low Earth Orbit (CLEO) onboard the constellation's UK-DMC satellite. Earth images are downloaded from the satellites using a custom IP-based high-speed transfer protocol developed by SSTL, Saratoga, which tolerates unusual link environments. Saratoga has been documented in the Internet Engineering Task Force (IETF) for wider adoption. We experiment with use of DTNRG bundle concepts onboard the UK-DMC satellite, by examining how Saratoga can be used as a DTN 'convergence layer' to carry the DTNRG Bundle Protocol, so that sensor images can be delivered to ground stations and beyond as bundles. This is the first successful use of the DTNRG Bundle Protocol in a space environment. We use our practical experience to examine the strengths and weaknesses of the Bundle Protocol for DTN use, paying attention to fragmentation, custody transfer, and reliability issues.

2011

Satellite communications are an interesting and promising application field for Delay/Disruption Tolerant Networking (DTN). Although primarily conceived for deep space communications and sensor networks, it was immediately recognized that DTN was applicable to satellite environments, in particular to cope with the intermittent channels typical of LEO (Low Earth Orbit) constellation satellite systems. The aim of this paper is to assess the advantages of DTN when applied to LEO satellites. Qualitative assessments are supported in selected cases by preliminary results obtained on a testbed based on GNU/Linux machines. In particular, two application scenarios have been considered, both using a single LEO satellite. In the former, we have one LEO satellite for Earth observation, connected to its gateway stations only at intermittent scheduled intervals due to its orbital motion. The latter is one LEO satellite acting as a "data mule" between a terrestrial sensor network and a remote satellite gateway station, which are never in the satellite coverage area at the same time. The results show the feasibility and the advantages of DTN in LEO satellite communications.

International Journal of Satellite Communications and Networking, 2010

We describe the first use from space of the Bundle Protocol for Delay-Tolerant Networking (DTN), and lessons learned from experiments made and experience gained with this protocol.

2010 IEEE Aerospace Conference, 2010

The University of Colorado is working with NASA to extend Earth's internet into outer space and across the solar system. The new networking technology is called Disruption Tolerant Networking (DTN), and is being tested on the International Space Station. DTN will enable NASA and other space agencies around the world to better communicate with international fleets of spacecraft that will be used to explore the moon and Mars. This technology is evolving into an Interplanetary Internet.

2009 First International Conference on Advances in Satellite and Space Communications, 2009

In October and November of 2008, the Jet Propulsion Laboratory installed and tested essential elements of Delay/Disruption Tolerant Networking (DTN) technology on the Deep Impact spacecraft. This experiment, called Deep Impact Network Experiment (DINET), was performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. During DINET some 300 images were transmitted from the JPL nodes to the spacecraft. Then they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. All transmitted bundles were successfully received, without corruption. The DINET experiment demonstrated DTN readiness for operational use in space missions. This activity was part of a larger NASA space DTN development program to mature DTN to flight readiness for a wide variety of mission types by the end of 2011. This paper describes the DTN protocols, the flight demo implementation, validation metrics which were created for the experiment, and validation results.

2010

The international space community has begun to recognize that the established model for management of communications with spacecraft -commanded data transmission over individual pair-wise contacts -is operationally unwieldy and will not scale in support of increasingly complex and sophisticated missions such as NASA's Constellation project. Accordingly, the international Inter-Agency Operations Advisory Group (IOAG) i chartered a Space Internetworking Strategy Group (SISG), which released its initial recommendations in a November 2008 report. The report includes a recommendation that the space flight community adopt Delay-Tolerant Networking (DTN) to address the problem of interoperability and communication scaling, especially in mission environments where there are multiple spacecraft operating in concert. This paper explores some of the issues that must be addressed in implementing, deploying, and operating DTN as part of a multi-mission, multi-agency space internetwork as well as benefits and future operational scenarios afforded by DTN-based space internetworking.

2008

This is the first successful use of the DTNRG Bundle Protocol in a space environment.

1997

Introduction -Challenges to intcroperability. + The Mobile Satellite Protocol Testbed -Goal -The Mobile Satellite Channel -Testbecl Capabilities: + Accurately model the satellite channel using propagation data. + Real-time test capability allows qualitative analysis. + Modified versions of standard TCP toots provide detailed logs.

Mobile Lightweight …, 2009

As the number and complexity of space missions increases, space communications enter a new era, where internetworking gradually replaces or assists traditional telecommunication protocols. The Delay Tolerant Network (DTN) architecture has recently emerged as a communication system for challenged networks, originally designed for the Interplanetary Internet. In the context of our project with ESA called "Extending Internet into Space -ESA DTN Testbed Implementation and Evaluation" we intend to deploy a distributed, flexible and scalable DTN testbed for space communications. The testbed will provide the supportive infrastructure for the design and evaluation of space-suitable DTN protocols, architectures, and routing policies to allow efficient deep-space communications. Throughout the project, we will demonstrate the operational capabilities of the DTN protocols in space; design and evaluate novel transport protocols and architectures for reliable data transfer in space; and investigate routing algorithms that comply with ESA's policies and resource status.