e users, handovers can occur when wireless link conditions change due to the users' movement. For the stationary user, handovers become imminent when the surrounding network environment changes, making one network more attractive than another. As an example, when making a network transition during a phone call, the handover procedures should be executed in such a way that any perceptible interruption to the conversation will be minimized. The standard supports cooperative use of information available at the mobile node and within the network infrastructure. The mobile node is well-positioned to detect available networks. The network infrastructure is well-suited to store overall network information, such as neighborhood cell lists, location of mobile nodes, and higher layer service availability. Both the mobile node and the network make decisions about connectivity. In general, both the mobile node and the network points of attachment (such as base stations and access points) can be multi-modal (i.e., capable of supporting multiple radio standards and simultaneously supporting connections on more than one radio interface). Figure 3-11 shows the Media Independent Handover Function (MIHF), i.e., a function that realizes MIH services, for IEEE 802.16 based systems. The M-SAP and C-SAP are common between the MIHF and Network Control and Management System. The M-SAP specifies the interface between the MIHF and the management plane and allows MIHF payload to be encapsulated in management messages (such as MOB_MIH-MSG defined in the IEEE 802.16-2009 standard [3]). The primitives specified by M-SAP are used by a mobile node to transfer packets to a base station, both before and after it has completed the network entry procedures. The C-SAP specifies the interface between the MIHF and control-plane. M-SAP and C-SAP also transport MIH messages to peer MIHF entities. The CS-SAP is used to transfer packets from higher layer protocol entities after appropriate connections have been established with the network. The MIH-SAP sp