Mobility Protocols and Handover Optimization: Design, Evaluation and Application

Chapter 3Systems Analysis of Mobility Events

In this chapter, we analyze the mobility event resulting from the handoff of a mobile node. In particular, we analyze the discrete operations of the mobility event in order to design a formal mobility systems model. However, we limit the analysis of the model to infrastructure-based mobility only. The infrastructure-based mobility model assumes that the layer 2 and layer 3 network components of the core networks, namely access points, routers, and servers, are not mobile and only the last hop of the access network changes. Figure 3.1 shows several different functional components in an IP-based infrastructure-based mobility environment. This figure includes the layer 2 and layer 3 points of attachment, the configuration agent, the authentication agent, the authorization agent, and the signaling agent, which perform the primitive handoff operations. During a mobility event, these network components are engaged in distributed communication to take care of the handoff-related operations. Figure 3.1 also shows how the mobile node changes its point of attachment as it moves between the layer 2 point of attachment, the layer 3 point of attachment, different administrative domains, and various access technologies. The labels A, B, C, and D in Figure 3.1 show the locations of the mobile node as it connects to different points of attachment during its movement. The mobile starts from the location marked A and moves to the locations marked B, ...