In this article, we present a study of DTN architecture over a typical relay-based space communication infrastructure, focusing on performance characterization of LTPCL in comparison with TCPCL. We have concluded that LTPCL has significant goodput performance advantages over TCPCL at all the experimented BERs (0??10??5) and channel ratios (1/1??500/1). The advantages of LTPCL over TCPCL are more significant for a higher channel ratio over a less lossy and moderately lossy (with BER ?? 10??6) space channel. When data loss and corruption events happen, unlike TCPCL, which implements the congestion control mechanism, LTPCL simply retransmits the lost and/or corrupted data without reduction of the data transmission rate. As a result, LTPCL achieves a very high transmission efficiency and thus a significant goodput advantage over TCPCL, and the significant performance difference between LTPCL and TCPCL with a high channel ratio (500/1) is mainly caused by a highly reduced ACK channel capacity associated with the different ACK traffic issued by receiver.