A comparative investigation of acknowledgment mechanisms for data transport in space internet

As the Internet is changing the world dramatically, an initiative is being proposed within NASA and in the military to expand the Internet into space and for network-centric warfare using network protocols. An end-to-end effective data transport protocol is critical to the reliable transfer of information in space and for a battlefield environment. Consequently, a reliable and efficient acknowledgment mechanism is required to accommodate these unreliable communication conditions. In this article we conduct a comparative investigation of existing data transport acknowledgment mechanisms for possible adoption in the unreliable environment of space or a similarly stressed communication environment. We also introduce the selective negative acknowledgment (SNACK), which is designed as a reliable retransmission mechanism for space and stressed tactical communications, followed by a brief performance evaluation of the effectiveness of SNACK compared to the standard SACK mechanism.