Mobility management in vehicular networks is our case study is to provide internet connectivity without any interruption and with no packet loss, even in V2I (Vehicular to Infrastructure) or V2V (Vehicular to Vehicular) communications. Handover delay is one of critical parameters in QoS measurements in addition to packet loss, throughput and data transmission delay. In this paper, the idea of Smart Buffering is proposed to enhance HI-NEMO protocol. In this extension of NEMO, the combining cross-layer mechanism and resource allocation have been performed. It is used to reduce latency and packet loss during handovers with high performance in its proactive mode. However, it is noticed that packets loss exists in its reactive mode during the period of link down in small coverage cell radius of base station during vehicle movement. Smart Buffering mechanism mostly prevents packet loss by buffering lost candidate packets in Root FMA (Foreign Mobile Agent), forwarding and reordering it in new FMA. It also performs redundant packet removing in Root FMA. Mathematical analysis proves that Enhanced HI-NEMO protocol prevents packet loss during reactive handover and gives optimal throughput with supporting high velocity vehicles.