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This paper introduces a fast handoff mechanism, NeighborCasting, for use in wireless IP networks that utilize neighboring foreign agent (FA) information. NeighborCasting is based on the policy of utilizing, or perhaps even wasting, wired bandwidth between foreign agents, while minimizing RF (radio frequency) bandwidth exchanges, so that handoff latency is minimized. We demonstrate that the handoff latency is substantially reduced, while the typical overhead is minimally increased. Handoff latency is minimized by initiating data forwarding to the possible new foreign agent candidates (i.e., the neighbor foreign agents) at the time that the mobile node initiates the link-layer handoff procedure. NeighborCasting builds upon the Mobile IP handoff procedure by adding a small number of additional message types. The handoff mechanism is a unified procedure for inter-domain, intra-domain and inter-technology (e.g., LAN to WAN or TDMA to CDMA) handoffs and provides flexible choices to the network, while maintaining transparency to the mobile node. The neighbor FA discovery process is a distributed and dynamic mechanism, and the fast handoff schemes are scalable and reliable.