Adaptive local route optimization in hierarchical Mobile IPv6 networks

Hierarchical Mobile IPv6 (HMIPv6) reduces the signaling overhead and the handoff latency associated with Mobile IPv6. Although the HMIPv6 protocol supports route optimization between a mobile node (MN) in the mobility anchor point (MAP) domain and a correspondent node (CN) outside the MAP domain, a non-optimal route is formed when the CN and the MN are located in the same MAP domain. In this case, the route can be optimized by informing the CN of the MN's on-link care-of address (LCoA) when the MN hands off within the domain. However, this optimization may result in a higher binding update cost when the MN hands off frequently. To balance the trade-off between the binding update cost and route optimization, we propose an adaptive local route optimization (ALRO) scheme. In the ALRO scheme, an MN informs the CN of the MN's LCoA if the packet delivery cost is more dominant than the binding update cost. Otherwise, the CN is aware of only the MN's RCoA. Namely, the ALRO scheme minimizes either the packet delivery cost or the binding update cost depending on the session-to-mobility ratio (SMR) of each CN. We analyze the performance of the ALRO scheme and derive the optimal SMR threshold. Numerical results indicate that the ALRO scheme shows a better performance than other RO schemes over a wide range of SMR.