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3 <title> DTN2 Manual: Introduction </title> |
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7 <h1>Introduction </h1> |
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8 |
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9 <p> |
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10 Congratulations! Welcome to the world of Disruption Tolerant |
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11 Networking. With a little help from this manual, and the DTN2 |
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12 software, you'll soon be sending bundles to Mars and beyond. |
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13 |
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14 <h2> What is Disruption Tolerant Networking? </h2> |
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15 |
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16 <p> The protocols that govern the way computers talk on the Internet |
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17 largely assume that there are reliable low latency connections |
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18 between any two points on the net. But several applications where we'd |
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19 like to get the benefits of computer networking do not conform to that |
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20 assumption. For instance, when NASA sends an instruction to a Mars |
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21 Rover, there are both latency (speed of light delay) and disruption |
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22 problems (no line of sight from Earth to Mars because the rover is on |
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23 the back side of Mars right now, or it is the weather is bad at the |
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24 receiving station). Another example is the challenge of |
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25 getting the benefits of the Internet to a villiage in a developing |
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26 nation. Traditional |
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27 telecommunications technology cannot reach it cost-effectively, but a guy |
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28 on a motorcycle can visit twenty such villages in a week much more cheaply |
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29 than one could build a network to those twenty villages. |
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30 |
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31 <p>The Disruption Tolerant Networking (DTN) family of specifications |
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32 and protocols lay out an architecture and mechanism to keep data |
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33 moving even in the face of the difficulties these new environments |
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34 present. For more information on DTN, visit the <a |
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35 href="http://dtnrg.org">DTN Research Group</a> web page. In |
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36 particular, download and read <a |
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37 href="http://dtnrg.org/tutorials/warthman-1.1.pdf">Forrest Warthman's |
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38 tutorial</a> for a great introduction to all the concepts and |
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39 terms in the DTN world. |
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40 |
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41 <h2> What is DTN2? </h2> |
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42 |
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43 <p> DTN2 is the name for a reference implementation of the DTN |
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44 protocols. It is designed as an experimental platform where |
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45 researchers can validate the protocol designs, and do experiments to |
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46 show that the DTN protocols are working as expected. For more |
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47 information about DTN2's architecture and role as a platform for |
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48 experimentation, see <a |
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49 href="http://www.cs.berkeley.edu/~demmer/papers/dtn-irb-tr-04-020.pdf">this |
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50 paper</a> by Michael Demmer and others. |
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51 |
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52 <p> Though DTN2 appeals to researchers, it is also intended to be |
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53 high-quality, production-grade code ready for use in real world |
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54 deployments. It has already been deployed to Cambodia and India |
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55 as part of the <a href="http://tier.cs.berkeley.edu">TIER, |
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56 Project</a>, to Swedish Lapland as part of the |
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57 <a href="http://www.n4c.eu/">N4C</a> project, and we |
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58 hope to see it deployed to many other environments that need to |
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59 benefits of a DTN. |
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60 |
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61 <h2> What protocols does DTN2 implement? </h2> |
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62 |
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63 <p> |
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64 DTN2 primarily implements The DTN Bundle Protocol defined in the experimental |
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65 specification <a href="http://www.rfc-editor.org/rfc/rfc5050.txt">RFC 5050</a>. |
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66 An RFC 5050-based DTN transmits data in the form of <i>bundles</i> that may be |
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67 much larger |
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68 than typical packets transmitted on IP networks. DTN2 also optionally supports |
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69 the Bundle Security Protocol to provide authentication and/or integrity |
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70 protection for transmitted bundles if required by the application. Bundles |
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71 can be transmitted over either over (IP) transport layers or various link layers |
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72 including Ethernet and Bluetooth. DTN2 implements a number of <i>convergence |
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73 layers</i> that interface between the Bundle Protocol and the transports. DTN2 |
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74 also provides a number of routing mechanisms to direct the forwarding of |
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75 bundles to their intended destinations including a <i>static</i> routing |
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76 scheme based on pre-configured routes and <i>epidemic</i> routing which |
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77 floods bundles to any node it encounters. |
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78 |
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79 <h2> What happened to DTN1? </h2> |
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80 |
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81 <p> |
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82 We have ceased working on DTN1 in favor of DTN2, which has a |
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83 significantly improved architecture for experimentation. DTN1 is |
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84 still available from the <a href="http://www.dtnrg.org/wiki/Code">DTN Research |
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85 Group</a> home page. You really should be using DTN2 for |
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86 any new experiments or deployments. |
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87 |
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88 </body> |
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