By introducing a mobility anchor point （MAP）, hierarchical mobile IPv6 （HMIPv6） reduces the binding update signaling cost associated with mobile IPv6, but there still exist deficiencies. For instance, a mobile node （MN） needs to orderly accomplish two binding updates with the MAP and home agent （HA） when the MN performs inter-MAP mobility. This results in a high signaling cost, thus affecting network performance. To reduce the inter-MAP binding update cost of idle MN in HMIPv6, an optimization scheme based on pointer forwarding with a threshold is proposed. The scheme can reduces the binding update cost of idle MN by using the binding update between MAP to replace several home binding updates. The signaling cost difference is derived by analyzing the cost of the basic scheme and the optimization scheme between two successive sessions. Simulation results show that, the optimization scheme can reduce the binding update signaling cost and improve the network performance as long as a suitable threshold is chosen. The discussions on the sensitivity of tele-parameters are also given.
LIU Yin-longZENG Zhi-minXIA Hai-lunZHANG Tian-kuiHAO Xiao-yan
