Inter-Domain Handover in WiMAX Networks Using Optimized Fast Mobile IPv6

The most attractive feature of WiMAX is arguable the mobility capability that IEEE 802.16e (IEEE, 2004) standard adds to the previous standard. With mobility support, handover has become one of the most important factors that impact the performance of IEEE 802.16e system. Handover is the process of maintaining active sessions of a mobile station when it migrates from current base station to target base station area. Handover occurs when a mobile station changes its point of attachment on the network. However during hard handover, the mobile station cannot receive or send any packet for a short time interval. This is referred to system disruption time because the services are interrupted or handover latency. In WiMAX, when a mobile node or mobile station changes its location, it moves the point of attachment to the network in two different scenarios;  The mobile station changes its point of attachment between the base stations which reside in the same Access Services Network (ASN) that is called ASN-anchored, intra, micro, or layer 2 handover. In an ASN-anchored handover, the mobile station resides within previous network address (both current and target base stations located in the same IP subnet). In this scenario, the mobile station does not change its IP configuration, only link layer is re-established.  The mobile station or mobile node changes its point of attachment between the base stations which reside in different ASN (different IP subnets) that is called Connectivity Services Network (CSN)-anchored, inter, macro, or layer 3 handover. In a CSNanchored handover, in addition to link layer handover a mobile node must perform a new IP configuration to avoid disconnection.