Host Identity Protocol (HIP) is a new protocol that employs the idea of separation of the role of IP addresses as host identification and location identifier. It also introduces protocol level security in its nature. It is manly designed for macro mobility as Mobile IP, but it has some shortcomings in terms of micro mobility regarding to signaling load and handover latency. Several researches and proposals have been introduced to enhance the micro mobility features of HIP. This paper is a survey on micro mobility techniques of HIP.