PMIPv6 is proposed as a new network-based mobility protocol and it does not require MN's involving in mobility signaling. PMIPv6 can handover relatively faster than MIPv6 because of using link layer attachment information and micro mobility characteristic. However, current PMIPv6 cannot prevent packet loss in disruption period. We proposed in this paper, Smart Buffering scheme for supporting seamless handover in PMIPv6. Smart Buffering scheme prevents packet loss totally by buffering lost candidate packets in a current serving MAG and forwarding it to a new MAG, after an MN successfully connected. Smart Buffering also performs redundant packet removing in a previous MAG and packet reordering in a new MAG to maximize performance of seamless handover. All these procedures between a previous MAG and a new MAG are processed using simple message exchanges without requiring any involving of an MN. We verified the effectiveness of the Smart Buffering by simulation with various parameters. Simulation results prove that proposed scheme prevent packet loss in the handover and handle buffered packets very efficiently. As a result, we conclude that Smart Buffering is very useful for supporting seamless handover in PMIPv6.