Introduction to DTN:
DTN is the term for Disruption Tolerant Networking (originally stood for Delay Tolerant Networking). Sometimes it is written as Delay/Disruption Tolerant Networking. Networking once involved huge computers that took up a large room and were stationary. Now networking devices are tiny and mobile. Wikipedia has an interesting article about The History of The Internet. There is an interesting article from How Stuff Works that shows how the Internet works and the (OSI) Open Systems Interconnection Reference Model works.
Information on the DTN Infrastructure:
Functional Specification for DTN Infrastructure Software
Interesting paper on DTN for Android devices - Delay Tolerant Network on Smartphones: Applications for Communication Challenged Areas
The InterPlanetary Networking Special Interest Group (IPNSIG) has a DTN Tutorial explain how a DTN can be used to form an Interplanetary Internet. The Interplanetary Overlay Network (ION) software distribution is an implementation of Delay-Tolerant Networking (DTN). IOAG Space Internetworking Strategy Group (SISG) & Space Internet Architecture Group (SIAG) has Information on a Recommendation on a Strategy for Space Internetworking and also Operations Concepts for a Solar System Internetwork.
The Delay-Tolerant Networking Research Group (DTNRG) lists various versions of DTN software to use. They also have lots of interesting Documents to read. DTN software is available for Debian and Ubuntu
The Internet Engineering Task Force (IETF) has an interesting memo on Delay-Tolerant Networking Architecture as well as the Bundle Protocol Specification (which is the core feature of a DTN). Techopedia has an introduction to the Bundle Protocol. The Bundle Protocol (BP) can work over Transmission Control Protocol (TCP). If TCP is not used at the Transmission layer of the OSI model, then Licklider Transmission Protocol (LTP) which goes over User Datagram Protocol (UDP) is used to Transmit the Bundles. Either BP/TCP or BP/LTP/UDP is used for BP transmission.