Mobility is seen as an integral part of future networks, where the initiatives for next generation networks (NGN) will meet more traditional and established networks to form heterogeneous architectures. IPv6 is the networking technology of choice in the effort to move to an all-IP 4G environment. In order to effectively support the integration of Cellular (3G),
Wireless LAN and Wireless Broadband (WiMax) technologies to the core networks, IPv6 and
Mobile IPv6 will be required to provide transport and mobility solutions over different access technologies. Mobility in IPv6 is therefore an enabler for future services and as such, all actions associated with it need to be thoroughly understood. One such action is the handover process. A handover (HO) is the process during which a mobile node (MN) creates a new connection and disassociates from its old one. The decision for a new association may be initiated due to movement, if we are moving away from the old connection point and we are approaching a new one; low signal quality, because of interference or other impairments in the wireless path; quality of service decision, trying to effect a balanced load among neighbouring or overlapping cells; better service, if we recognize a network with services that we require; or policy and cost decision, where the network or the user decide that it is more appropriate, or advantageous to relate to a different location.
Handovers can be characterized as Horizontal if they are performed between connection points using the same access technology, or Vertical if they are performed between access points of different technologies, a case which will be more common in future heterogeneous networks.
In addition, Handovers are considered Link Layer (L2) if they are performed between connection points belonging to the same subnet, or Network Layer (L3) if