Use of a hybrid of DTN convergence layer adapters (CLAs) in interplanetary Internet

Some work has been done with the DTN convergence layer adapters (CLAs) such as TCP-based CLA (i.e., TCPCL), Licklider transmission protocol CLA (i.e., LTPCL) and user datagram protocol (UDP)-based CLA (i.e., UDPCL) in space communication, running as an individual protocol. Because each DTN CLA is designed for a different type of communication link, using any single CLA under BP is generally inefficient over a heterogeneous end-to-end interplanetary infrastructure. In this paper, we propose to use a hybrid of DTN CLAs for efficient file transmission in interplanetary environment, i.e. using one CLA for one hop of the end-to-end path and a different CLA for another hop of the path. Based on experimental investigation of DTN protocols over a typical relay-type of interplanetary infrastructure, we found that a hybrid of TCPCL and LTPCL has significant goodput advantage over single-CL-protocol configurations at long link delays, especially with a high BER, and a transmission with LTPCL utilized over a long-delay hop is more tolerant of long channel delay and high channel error.