DTTP: a Delay-Tolerant Transport Protocol for Space Internetworks

We propose Delay-Tolerant Transport Protocol (DTTP) to address reliable data transfer in stressed network environments, such as space communications. Since existing TCP mechanisms do not work well (or at all) for such networks, new transport schemes are required. Intermittent connectivity in space environments calls for new transport approaches that smoothly adapt to the special networking conditions. DTTP is primarily a transport layer protocol and satisfies the inherent architecture requirements of Delay Tolerant Networking (DTN) in the absence of IP network infrastructure. It allows for reliable, efficient data transfer offering a number of application-oriented transmission strategies. Otherwise, when an IP architecture exists, DTTP operates as a standalone transport entity which interfaces with IP directly. We introduce the protocol's properties and functionality that enable its deployment in challenged networks. We conduct simulations that demonstrate the protocol's efficiency in scenarios with: (i) long propagation delays, (ii) minimum to relatively high packet error-rate, and (iii) intermittent connectivity.