Mobile Inter-networking with IPv6 : Concepts, Principles and Practices

14

Fast Handovers

The biggest difference between time and space is that you can’t reuse time.    –Merrick Furst

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In this chapter, we introduce the basic concepts behind fast IP handover, which allows a mobile node to quickly regain its IP connectivity in order to send and receive its payload immediately following a handover. Fast handovers are necessary for realtime applications such as VoIP. Since delay and packet loss are significantly reduced, they assist traditional TCP applications as well. We describe the Fast Handovers protocol specification [11] itself in Chapter 15.In Chapter 16, we describe context transfer, a technique to smooth the effect of routing change on transport protocol performance by eliminating the need to re-establish any network-resident contexts, such as access control and QoS. Together, the protocols provide necessary ingredients to build effective system solutions for supporting a variety of applications in a mobile networking environment.

14.1 SNAPSHOT OF A MOBILE NODE’S ACTIONS

Consider a mobile node that attaches to its access network, typically through a wireless link, using an access point or a base station. The access point provides link connectivity, and the access router provides IP connectivity. Although the access point and access router are separable functional entities, they both could be integrated in a single physical device. Since we are ...