Problem Description: Reasons For Performing Context Transfers Between Nodes in an IP Access Network

In IP access networks that support host mobility, the routing paths between the host and the network may change frequently and rapidly. In some cases, the host may establish certain routing-related services on subnets that are left behind when the host moves. Examples of such services are AAA, header compression, and QoS. In order for the host to obtain those services on the new subnet, the host must explicitly re-establish the service by performing the necessary signaling flows from scratch. In some cases, this process would considerably slow the process of establishing the mobile host on the new subnet. An alternative is to transfer information on the existing state associated with these services, or context, to the new subnet, a process called 'context transfer'. This document discusses the desirability of context transfer for facilitating seamless IP mobility.