InterPlanetary Networking Special Interest Group (IPNSIG) Rotating Header Image

Motivation for DTN: Terrestrial Use Cases

Many people new to InterPlanetary Networking are surprised to discover that DTN is also considered effective for many terrestrial use cases. That’s because the same kind of constraints exist in many networking environments right here on planet earth. These primarily include disruptions and delays—or perhaps even the absence of traditional Internet infrastructure that would make network communications via TCP/IP unfeasible or prohibitively expensive.

It’s not too difficult to envision some of those environments. Some constraints are inherent in the communication environment itself:

  • Like water as a communication medium. RF waves do not propagate well, but sound waves do, which are incredibly slow and whose speed varies unpredictably with the density of the water column.
  • Or think of underground applications like mining. Cable can be expensive to lay and subject to disruption through unintentional damage by mining equipment. RF does not penetrate the earth.
  • First responders searching through rubble are subject to unpredictable disruptions caused by loss of LOS with wireless signals.
  • Battlefield sensors cannot maintain constant RF contact for security reasons.
  • Finally, many regions that would benefit from Internet services find them unavailable (or prohibitively expensive) simply because they are not located where traditional Internet infrastructure exists. A look at any light pollution map shows you how much of the world does not have ready access to traditional Internet infrastructure.

Light Pollution



Examples of experimental implementations of DTN to overcome these constraints include:

  • Providing basic Internet services to reindeer herders in the Arctic Circle in Sweden.
  • Monitoring air quality in a karst cave in Romania.
  • Monitoring the cardiac health of first responders during emergency operations
  • Providing basic Internet services to remote villages in Africa that had no access to traditional network infrastructure

An area of particular interest to the DTN community is the Internet of Things (IoT), where communication is primarily amongst things and not people: sensors in buildings, roadways, on farms and even in our bodies. Because of the mobility of many of these Things, and limitations in power and signal strength, continuous end-to-end connectivity is either not achievable at all, or not maintainable. Since DTN assumes that such continuity does not exist, it can perform a valuable function in the world of IoT (sometimes call the “DTN of Things”)

Our next blog will dive into DTN’s potential role in IoT in more detail.

This blog is a product of the usual suspects: Scott Burleigh (NASA/JPL); Keith Scott (Mitre Corp./CCSDS and Mike Snell (IPNSIG)


DTN Motivation for Space Communications

As NASA contemplated longer space missions involving multiple spacecraft, they foresaw the need for network automation, much the same as exists on the terrestrial Internet. Missions had to include not only coding for the applications to perform navigation and scientific observations—they also had to support communications with earth. NASA wanted to standardize and automate network communications in space, and at interplanetary distances.

Network automation is a huge advantage of the terrestrial Internet. Application developers in general do not have to worry about the performance of the network, and TCP/IP requires relatively little centralized administration. The Transmission Control Protocol (TCP) in particular, assures reliable communication for applications (almost anything of significance on the Internet uses TCP). TCP does this through a series of exchanges back-and-forth between the sending and receiving hosts in order to establish a communication session; establish communication speed and verify that all of the disparate pieces of a message have been properly received and reassembled at the destination in the right order. If anything is missing, it gets retransmitted.

All of these behind-the-scenes messages between sender and receiver assume that a communication pathway exists between the two that is almost instantaneous in nature. If that assumption breaks, TCP breaks. The session times out and must be re-established.

TCP works relatively well on planet earth because the velocity of light provides almost instantaneous bidirectional communication speeds given the relatively short distances involved (after all, a photon could circumnavigate the globe about 7.5 times a second). However, NASA was contemplating traveling very long distances indeed. The minimum distance from Earth to Mars is about 54.6 million kilometers (about 33.5 million miles). The farthest apart they can be is about 401 million km (about 350 million miles). The average distance is about 225 million km (about 140 million miles). This means round trip times for radio frequency communications ranging from a minimum of about 7 minutes to a maximum of about 40 minutes.

Not only would communications at interplanetary distances involve many, many times the signal delay experienced on earth, but they would also experience significant periods of disruption. Planets have this pesky habit of rotating. Anything on the surface of Mars would experience long periods of communication blackouts while the planet Mars itself blocked line of sight with the earth.

While other factors also constrained data communications at interplanetary distances, delay and disruption were the two primary limitations preventing the architecture of the terrestrial TCP/IP Internet from working in that environment. Which is how Delay/Disruption Tolerant Networking (DTN) got its name.

How to deal with this extreme environment? Change the store-and-forward (albeit for only a few milliseconds) architecture of the Internet to what has come to be called a “store-carry-and-forward” architecture. This uses local storage in network devices themselves to hold onto a much larger “bundle” of data (than an IP packet), and only forward that packet onto its target destination when an opportunity to do so presents itself.

We’ll be explaining this architecture in more detail in future blogs, but first, we’ll explain how DTN, which was designed for use in outer space, has very useful applications in network environments displaying very similar constraints right here on planet earth. That will be the topic of our next blog…

This blog is a product of the usual suspects: Scott Burleigh (NASA/JPL); Keith Scott (Mitre Corp./CCSDS and Mike Snell (IPNSIG)



IPN Video Resources


As promised, here are a number of short videos (none over 7 minutes) that explain basic elements of DTN. Some also include historical information and explanations of the problems DTN solves in constrained environments.

IPNvideo1 Short (slightly under two minutes) simple animation developed by JPL to explain the basic problems that DTN solves and the basic store-carry-forward architecture.





IPNvideo2 A slightly longer (about 5 minutes) and slightly more technical animation developed by JPL to illustrate how DTN store-carry-forward approach and custody transfer work. Basically audio playing against a simple (and non-changing) background with an animated speaker. Good verbal content, but in the later portions, it presupposes a level of computer networking knowledge that would probably make the content difficult for a newbie to absorb.


IPNvideo3 Another simple NASA video that should be useful for the newbie. This one graphically demonstrates how DTN significantly increases throughput compared to traditional IP in a space data communications environment.






IPNvideo4 Another pretty simple JPL animation that should be easily understood by the newbie. This one graphically compares the throughput of TCP, UDP and DTN—particularly emphasizing the difference in data throughput between TCP and DTN and the difference in data loss between UDP and DTN.






IPNvideo5 NASA Jet Propulsion Laboratory. Disruption Tolerant Networking Summary comprised of video clips and animations. Vint Cerf is prominently featured, but if you look carefully, you can spot other IPNSIG board members (Scott Burleigh and Jay Wyatt) and friends (Leigh Torgerson)..

This is the first of a number of blog entries designed to help newbies come up to speed on Delay & Disruption Tolerant Networking. If you find an online article you think others would be interested in, or if there is a topic you would like to see covered in future blogs, drop a note to

What if I don’t know anything about IPN?


Many members of IPNSIG may be familiar with the technologies behind the traditional Internet, but be completely new to the domain of Interplanetary Networking and DTN (Delay & Disruption Tolerant Networking). While there are hundreds of technical articles available about different aspects of DTN, these articles typically assume previous knowledge of the technical foundations of the protocols and the problems they are attempting to solve. One can always turn to RFC’s… but they also assume the reader is “in” on the technical context.

What is a newbie to do?

There are a number of terse introductory videos and online documents available to help newbies come up to speed, and some on them are available on the website. Here’s a couple:

A short TED Talk by Vint Cerf explaining the very basic challenges IPN presents and DTN’s approach to addressing them:

A terse technical introduction to DTN, covering most major topics. Many thanks to Forrest Warthman of Warthman Associates) for authoring this latest version (and Scott Burleigh of NASA/JPL for technical consultation and review).

However, if you really want to understand Interplanetary Networking and DTN, we’d suggest you investigate a couple of recently published books that provide both a solid overview of the history, architecture and technologies involved in DTN:

  • Delay and Disruption Tolerant Networks: Interplanetary and Earth-Bound — Architecture, Protocols, and Applications CRC Press – Aloizio Pereira da Silva (Editor), Scott Burleigh (Editor), Katia Obraczka (Editor) – 2018
  • Delay-Tolerant Satellite Networks (Space Technology and Applications) Artech House – Juan A. Fraire (Author), Jorge M. Finochietto (Author), Scott C. Burleigh (Author) – 2017

While books like these represent an investment in time and money (there is a Kindle edition available at deep discount for Delay and Disruption Tolerant Networks: Interplanetary and Earth-Bound — Architecture, Protocols, and Applications), there is much to be gained by plowing one’s way through them. Both contain excellent introductory content that lays a good foundation for the reader in understanding later technical topics.

As the title indicates, Delay-Tolerant Satellite Networks (Space Technology and Applications focuses almost exclusively on DTN in space data communications. The more limited scope allows the authors to explain not only DTN, but also the existing and planned space communications infrastructure upon which it operates.

Delay and Disruption Tolerant Networks: Interplanetary and Earth-Bound — Architecture, Protocols, and Applications expands the arena for DTN to include the many, many terrestrial applications for addressing constrained network environments. These run the gamut from enabling email delivery for reindeer herders in the Arctic Circle to providing basic Internet services to villagers in rural Africa. There’s an entire chapter devoted to DTN’s usefulness in the burgeoning world of the Internet of Things (IoT).

There is also the first book-length treatment of DTN from back in 2006:

  • Delay- and Disruption-Tolerant Networking - Artech House Publishers – Stephen Farrell, Vinny Cahill – 2006

Stephen Farrell was the co-chair of the DTN Research Group. This book is most useful for an understanding of the history of DTN development and why it is so necessary for both interplanetary and constrained terrestrial networking environments.

Still daunted?

We are all newbies at some point in understanding any topic in depth. It can be overwhelming. We encourage you to take advantage of some of the resources highlighted in this blog posting. We’ll be focusing on online video resources introducing you to the world of DTN in our next blog entry.

This blog is a product of the usual suspects: Scott Burleigh (NASA/JPL); Jay Wyatt (NASA/JPL); Keith Scott (Mitre Corp./CCSDS) and Mike Snell (IPNSIG)


DTN Content from JPL/NASA







Some new content has recently become available that I believe IPNSIG members would find interesting.

Leigh Torgerson, IPNSIG member and Space Communications Networking Architect from JPL/NASA, has posted some useful animations explaining Delay and Disruption Tolerant Networking concepts. It’s available for viewing at:

Leigh also recently made a presentation that was even more recently released for publication. It’s available here: 332-Section-DTN-Seminar-2019-for-Public-Release–final

The presentation provides fairly detailed historical background, an explanation of why Internet protocols do not work in space, and a picture of where DTN is going in the near future.


Announcing IPNSIG Blog

Welcome to the InterPlanetary Networking Blog! We intend to make this a weekly publication of interest to everyone interested in InterPlanetary Networking (IPN), Delay & Disruption Tolerant Networking (DTN), and computer networking in general.

Since this is the inaugural blog entry, we thought it would be useful to back up a bit and answer some basic questions:

What is IPN?

It is a solution to the constrained network environment present in space data communications and, more generally, in the emerging Internet of Things.

TCP/IP, the core technology [BSC(1] running today’s Internet, assumes essentially instantaneous, continuous end-to-end connectivity, and fails when it encounters delay or disruption of any significant length (about 4 seconds).

However, delays and disruptions are inherent in data communications at interplanetary distances, with the shortest Round Trip Time (RTT) for a radio signal to travel to Mars and back being about 7 minutes. Other factors contribute to the network constraints existing in interplanetary communications, but delay is the most significant factor making existing Internet protocols impractical for use.








Enter DTN:

Adrian Hooke (Sr. Technical Director with the Jet Propulsion Laboratory, NASA) meets Vint Cerf (co-author of the TCP/IP protocols and one of “Fathers of the Internet”) in the late 1990’s. They discover they both want to provide the same kind of network communications automation in space networking that works so well on the Internet.

Vint Cerf gets to work. A terse history follows:

  • DARPA funds work at JPL.
  • Core experimental “delay-tolerant networking” protocols developed by JPL, MITRE, Sparta researchers.
  • ION implementation of DTN developed at JPL for use by NASA.
  • DTNRG established to mature the protocols.
  • ION demonstrated on the EPOXI spacecraft in deep space.
  • ION deployed for all science payload communications on ISS.

Where is IPN today?

  • IETF DTN Working Group formed to establish DTN protocols as Internet standards.
  • Consultative Committee for Space Data Systems (CCSDS—a global standards setting organization for civilian space flight) standards adoption well underway.
  • Security Protocols maturing (including Public Key Infrastructure—PKI).
  • Dr. Scott Pace (White House Space Policy Director) challenges NASA to use DTN for all space communications (see for Dr. Pace’s presentation at our 2015 IPN Speakers Conference).
  • NASA integrating DTN into ground networks and future spacecraft.

IPN’s bright future

  • Increasing standardization amongst civilian space agencies.
  • Increasing international research into DTN for constrained terrestrial as well as space networking environments.
  • Coming adoption as internet standards.


What’s next for the blog?


Each week, we will post news about the exciting world of IPN, or summaries of academic research, or links to IPN in the mainstream media. We’ll also be announcing upcoming IPNSIG events and activities. We hope you enjoy the blog.


This blog is a product of the usual suspects: Scott Burleigh (NASA/JPL); Jay Wyatt (NASA/JPL); Keith Scott (Mitre Corp./CCSDS) and Mike Snell (IPNSIG)

DTN Article Published on Discover Magazine Blog Site

Thanks to board member Vint Cerf for bringing this to our attention.

Members might be interested in this article, slanted towards a general audience. It provides a brief overview of some of the history of DTN and includes news about including it in the PACE environmental monitoring satellite mission in 2022. Enjoy the read… it’s good to see DTN get some coverage in popular media.



Live Stream of Private Space Science 2018

Joly MacFie of the NYC Chapter will be streaming this weekend’s (June 2nd & 3rd) Dawn of Private Space Science 2018 speakers conference from Columbia University in New York City. Event details, including the speakers and schedule, are avalable here: Joly’s stream will be available on the Internet Society’s LiveStream channel:

This should be an event of interest to all members!
Mike Snell

MITRE Publishes Updated DTN Development Kit

Thanks to IPN-ISOC Board Member Keith Scott of Mitre Corp. for providing the contents for this post!


Thanks to MITRE’s Technology Transfer Office, the latest version of the DTN Development Kit is now hosted on a MITRE server and available for download:

The Development Kit ISO is an Ubuntu VM with ION 3.5.0, the Common Open Research Emulator (CORE), and some utilities to help users get started with DTN, and ION in particular.  CORE is a virtualization environment that allows for easily running multiple ION nodes and controlling the connectivity and communication parameters (latency, packet loss rate, etc.) among them.  Sample scenarios are included that emulate constantly-connected nodes (for easy testing), a data mule scenario, a Mars scenario, and an Earth-observing satellite scenario.  In the sample scenarios, connectivity is controlled by an emulated wireless link and a simple mobility script.  ION contact plans are synchronized to the mobility script to allow testing of scheduled connectivity.  [NB: this process is not perfect, the contact plans may end up misaligned by a few seconds, so contacts that last several 10s of seconds are recommended.  Also, many of the scenarios rely on IP routing to reach even next-hop neighbors (e.g. if a next-hop neighbor has multiple interfaces) – it may be necessary to wait 30s or so at the beginning of a scenario for OSPF to converge before BP can take over and function.]

To run any of the scenarios, boot the virtual machine and log in as user: core  password: cvm  and start the core-daemon with ‘core-daemon &’, then start the core-gui with ‘core-gui &’.  From there you can use the file menu to navigate to the DTN Dev Kit Scenarios under ~/.core/configs and launch one.  There’s documentation in the NSA_DTN_CORE_Scenarios folder in the user’s home directory.

Screenshots of the scenarios:

A simple scenario with a satellite that moves in and out of range.







A Mars scenario with 3 ground stations, a rover, and an orbiter.










An Earth-observing satellite scenario with multiple ground stations:











Network Management

A new and relatively untested feature: the DevKit now incorporates an Elasticsearch / Logstash / Kibana (ELK) stack and simple scripts to exercise ION network management. The network management script DOES require that you (one time) follow the instructions below  Everything below will be done automatically in future versions of the Dev Kit, but for now:


[Ensure you have your http_proxy and https_proxy environment variables set]

Run:       sudo -E apt-get install python-pexpect

From within the DevKit VM, start Firefox and go to localhost://5601 to get the Kibana interface.  Select the ‘Settings’ tab in the top ribbon.  If ‘bpnm’ show up under the ‘Index Patterns’ on the left side, select it and click the red trash can to delete it.

From the ~/NASA_DTN_CORE_Scenarios/CORE_configs/3GS/MO/link/NMConsole directory, run the following to set up the datatypes in the Elasticsearch database.  This needs to be run from a terminal on the DevKit VM itself (NOT one of the emulated machines inside CORE that are running ION).

Run:       sudo ./

Again click on the Kibana page with the ‘Settings’ tab, so that it says “Configure an Index Pattern” and in the bar where you can type, type ‘bpnm’ (no quotes).  This should enable the ‘time-field name’ selection, where you want ‘receive_timestamp’.

NOTE: yes, there’s a ‘SendTimestamp’ that you might think would be better, but I think SOMEBODY (probably me) in the chain doesn’t handle daylight savings time right –  send timestamps come out an hour in the future, so until that gets sorted out, let’s stick with receive timestamps.













Network management is only enabled in the 3GS scenario.  In the 3GS scenario, double-click on the ‘MO’ node (ION node 5 in the lower left) and cd into the NMConsole directory of the node.  The script will pull basic network management information from a node and insert it into an elasticsearch database (do ‘ –h’ for usage, but ‘ –m ipn:5.6 –a ipn:2.5’ will pull information from node 2).  You can then get at the data from Kibana by going to the ‘Discover’ tab and selecting ‘bpnm’ from the list of index patterns (dark grey bar upper left)












Future enhancements will include scripts that will plot e.g. the number of bundles resident at a node over time, etc.

Letter to Members re ISS DTN Go Live

Dear Chapter Members–

An item of interest for you:

NASA has just announced that Delay & Disruption Tolerant Networking (DTN) has just gone live for all communications to the International Space Station (ISS). This is a really significant step forward for DTN and InterPlanetary Networking. While DTN has been used since 2010 for communications between scientists on the ground and their scientific payloads onboard ISS, NASA had to be much more careful in deploying ISS for operational communications, which are critical to crew safety and flight operations. It took over a year to review and approve the Change Request. NASA’s decision to go live with DTN is a huge vote of confidence for its reliability and fitness-to-task for space communications.

Here is a link to the official NASA announcement:

Many, many people and organizations have worked for many years to make this a reality. Key organizations include the the DTN Research Group of the Internet Research Task Force, who developed and tested the protocol suite; Jet Propulsion Laboratory, who developed the Interplanetary Overlay Network (ION) implementation of DTN, and the Consultative Committee for Space Data Systems (CCSDS), who reviewed and approved the Bundle Protocol and Licklider Transport Protocols for use in civilian space flight.

We are fortunate to have members of our Chapter and our Board who have been key players in this effort. These include:

Board member Vint Cerf, widely recognized as one of the “Fathers of the Internet” for his work on the design of the TCP/IP protocols and the architecture of the Internet, also helped secure the DARPA funding to launch the initial InterPlanetary Internet studies within NASA/JPL.

Vice Chair Scott Burleigh, who has led the development of the ION implementation of DTN (which is the version in use on ISS). He coauthored the DTN Architecture definition (Internet RFC 4838) and also the specification for the DTN Bundle Protocol (BP, Internet RFC 5050).  In addition, he is a co-author of the specifications for the Licklider Transmission Protocol (LTP, Internet RFCs 5325 through 5327).

Board member Keith Scott began working on the Interplanetary Internet in 1998, implemented a precursor to the current Bundle Protocol, and is co-author of the Bundle Protocol (RFC 5050).  Keith currently serves as Area Director for Space Internetworking Systems for the Consultative Committee for Space Data Systems (CCSDS) and leads the CCSDS DTN working group that is standardizing DTN protocols for use in civilian space missions.

Board member Jay Wyatt who, through his role in managing the JPL Space Networking and Mission Automation Program Office has led various DTN development activities including the first deep space flight validation of DTN on NASA’s EPOXi mission.  Currently Jay is the programmatic point of contact for DTN development at JPL and is involved in pursuing various opportunities to infuse DTN into upcoming deep space missions and to complete development of the DTN software suite.

And, finally, we want to acknowledge our departed colleague, IPNSIG Board Member and tireless advocate of DTN, Adrian Hooke, who led the interplanetary networking initiatives within NASA/JPL for many years. Please see for more information about Adrian’s contributions to the field.

Mike Snell

President, the InterPlanetary Network Chapter

  • Categories

  • Become a member of IPNSIG

    We're now a Chapter of the Internet Society! It’s simple! Just go Here and fill out the membership form. You will receive a confirming email when you have been added to our membership rolls.