Signaling Cost Analysis of Handoffs in a Mixed IPv4/IPv6 Mobile Environment

The rapid growth of the Internet has led to the anticipated depletion of the addresses in the current version of the Internet protocol (IP), IPv4. This depletion has given rise to a newer version of the Internet protocol, internet protocol version 6 (IPv6). IPv6 provides sufficient address space to meet the predicted increase of the internet. Since IPv4 has been widely deployed, it is required that the existing IPv4 and the newly added IPv6 can co-exist and interoperate. Various mechanisms have been proposed for supporting the interoperability between IPv4 and IPv6. However, they are mostly designed for a static environment. Mobility introduces a new dimension to the problem of IPv4/IPv6 transition and interoperability. The mobility support of mobile terminals in a mixed IPv4/IPv6 environment remains largely unexplored. In this paper, we analyze various handoff scenarios for a dual stack mobile node with a predominant IPv6 home address (DSMNv6) roaming in a mixed IPv4/IPv6 environment. We investigate how handoffs can be supported and derive the handoff procedures for all scenarios. We also design an analytical model for the handoff signaling cost analysis. Numerical results are provided to demonstrate the signaling cost of various handoff scenarios. Conclusions from this study can give great insights in designing new cost-effective mobility-support mechanisms for IPv4/IPv6 transition and interoperability.