The demand for mobile service increase many service providers which they start finding solutions for integrating third and fourth generation networks and to develop mobility protocols. This article introduces the macromobility, micromobility, and ad hoc routing protocols the Internet Engineering Task Force (IETF) has discussed. The aim is to familiarize readers with various mobility protocols, point out differences, and generate interest to pursue research. Cellular IP can perform handoffs in a number of ways, and it uses an efficient paging technique. To achieve this, it uses two mappings: paging cache (PC) and routing cache (RC). PCs are used only to search for (mobile node) MNs while RCs are used to route data to the MNs. Micromobility protocols complement MIP by reducing signaling overheads and enabling faster handoffs for seamless connectivity. These protocols handle local movements of MN without any interaction with MIP. It reduces the bandwidth consumption and another advantage of reducing signaling overheads is that it helps to conserve the power reserves of MNs.