Mobile IPv6 (MIPv6) allows hosts to move their physical and topological attachment points around an IPv6 network while retaining connectivity through a single, well-known Home Address. Although MIPv6 has been the subject of simulation studies, the real-world dynamic behavior of MIPv6 is only gradually being experimentally characterised and analysed. In this paper we review the use of MIPv6 to support mobility between independent 802.11b-attached IPv6 subnets, and experimentally measure the how long an end to end IP path is disrupted when a MIPv6 node shifts from one subnetwork to another (hand-off latency).We also measure 802.11b hand-off independent of MIPv6. Our testbed is implemented using FreeBSD 4.x, the KAME MIPv6 stack, Cisco Aironet Access Points and NetGear 802.11b network interface cards. Using our measured hand-off latencies we evaluate the likely performance impact of MIPv6 hand-off on a common webcam application and bulk TCP data transfers.