TCP Convergence Layer-Based Operation of DTN for Long-Delay Cislunar Communications

Delay/disruption tolerant networking (DTN) is a class of network techniques developed to accommodate long link delay and frequent link disruptions. Little work has been done in evaluating the effectiveness and performance of the DTN protocols when they are applied for an interplanetary Internet (IPN). In this paper, we present an experimental evaluation of Transmission Control Protocol Convergence Layer (TCPCL)-based operation of DTN-2 (i.e., TCPCL/TCP) for long-delay cislunar communications, partially in comparison with Licklider Transmission Protocol (LTP)-based LTP/User Datagram Protocol (UDP). The experiment is conducted by transmitting a text file using the DTN protocol stack over a PC-based simulation test-bed. According to the experimental results, the TCPCL-based DTN protocol works effectively over less error-prone cislunar links with short delay and has performance advantage over LTP-based DTN. Along with the increase in link delay and channel noise, the performance of TCPCL-based DTN is getting far behind the LTP-based DTN. The TCPCL-based DTN protocol can successfully handle an experimented short link disruption around 30 s-120 s, even with an existence of a very long link delay and a high channel Bit-Error-Rate (BER), but its performance is poor compared to that of the LTP-based DTN.