Introduction

The Host Identity Protocol (HIP) and architecture is a new piece of technology that may have a profound impact on how the Internet will evolve over the coming years. The original ideas were formed through discussions at a number of Internet Engineering Task Force (IETF) meetings during 1998 and 1999. Since then, HIP has been developed by a group of people from Ericsson, Boeing, HIIT, and other companies and academic institutions, first as an informal activity close to the IETF and later within the IETF HIP working group (WG) and the HIP research group (RG) of the Internet Research Task Force (IRTF), the research arm of the IETF.

From a functional point of view, HIP integrates IP-layer mobility, multihoming and multi-access, security, NAT-traversal, and IPv4/v6 interoperability in a novel way. The result is architecturally cleaner than trying to implement these functions separately, using technologies such as Mobile IP, IPsec, ICE, and Teredo. In a way, HIP can be seen as restoring the now-lost end-to-end connectivity across various IP links and technologies, this time in a way that it secure and supports mobility and multi-homing. As an additional bonus, HIP provides new tools and functions for future network needs, including the ability to securely identify previously unknown hosts and the ability to securely delegate signaling rights between hosts and from hosts to other nodes.