This document summarizes three routing protocols for mobile ad hoc networks: Dynamic Source Routing (DSR), Zone Routing Protocol (ZRP), and Destination-Sequenced Distance-Vector Routing (DSDV). It compares reactive and proactive routing protocols, and classifies ZRP as a hybrid protocol. The document provides an overview of the challenges of routing in mobile ad hoc networks and categorizes common routing protocols as proactive, reactive, or hybrid.