In this thesis, we propose a low-latency handoff scheme for Mobile IP using link layer information to perform a registration process with a new mobile agent immediately after the completion of link Iayer handoff. The proposed scheme was designed to reduce handoff latency when the Mobile IP protocol operates over the infrastructure mode wireless LAN where a link layer handoff is hard and forward. We implemented our scheme in a testbed and showed its operability by running a Voice over IP application on handheld mobile devices, such as PDA. We measured and analyzed the end to end delay of interactive voice communication between laptop PC and PDA to investigate the performance of PDA for real-time services. Our experimental results show that the proposed scheme considerably reduces the handoff latency of Mobile IP so that real-time multimedia applications can be appropriately accommodated in the mobile Internet.