This document provides guidance on routing topics for PhD research and lists the most important routing protocols. It outlines foremost topics in routing such as shortest path routing protocols, delay constraint routing, and broadcast/unicast routing. Current routing technologies discussed include segment routing, tri-band WiFi, routing mesh, blockchain, and MU-MIMO. The most important routing protocols listed are AMQP, OSPFv3, EIGRP, RIPv2, and IGRP. Contact information is provided at the end for those seeking additional guidance on PhD topics in routing.