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

16

Context Transfers

What’s sort of interesting about the whole public relations disaster that is the Net, in some ways, is that the fundamentals are really good.    –Meg Whitman

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16.1 INTRODUCTION

In the previous chapters, we have studied fast handovers in detail. We have studied the basic concepts and the protocol details. With careful system design, the basic protocol can be used to minimize latency and reduce or eliminate packet loss during a subnet handover. In this chapter, we will investigate a companion protocol for achieving smooth handovers. Fast handovers are primarily concerned with routing operations such that packet forwarding can take place as soon as new link establishment occurs. Without such support, basic packet forwarding would not take place in a timely fashion.

In addition to expedited routing operations, however, additional transport-level operations may be necessary to further improve the handover experience. For instance, assume a VoIP packet stream running on a mobile node which is afforded certain QoS on an access link. At the IP layer, this typically involves appropriately classifying the packet stream as a VoIP stream and providing the desired queuing support to ensure low latency and near-zero packet loss. In order to also ensure that the stream follows an agreed-upon traffic contract, the stream is also metered and shaped (or policed) if necessary. ...