Huawei Technologies Co.,Ltd Huawei Technologies Co.,Ltd HIP proxies play an important role in the transition from the current Internet architecture to the HIP architecture. A core objective of a HIP proxy is to facilitate the communications between legacy (or Non-HIP) hosts and HIP hosts while not modifying their protocol stacks. In this document, the legacy hosts served by proxies are referred to as the Made-up Legacy (ML) hosts. Currently, various designing solutions of HIP proxies have been proposed. These solutions may be applicable in different working circumstances. In this document, we attempt to investigate these solutions in detail and compare their performances in different scenarios.