The document summarizes the Ad-Hoc Transport Layer Protocol (ATCP). ATCP addresses issues in mobile ad hoc networks like packet loss, route changes, network partitions, and out-of-order packets. It functions as a thin layer between TCP and IP on the sender side, and has states to handle normal transmission as well as loss, congestion, and disconnection. While ATCP maintains TCP semantics and compatibility, it relies on the network layer to detect route changes and additions a new ATCP layer.