In ATM networks, the guaranteed frame rate (GFR) service category has been defined to support user applications which are neither able to specify the range of traffic parameter values, nor able to comply with the behavior rules. It provides a packet-level rate guarantee with a given maximum packet size. The service specifies that the excessive traffic from a user should share the available resource fairly. In this paper, we investigate TCP/IP packet transmission over ATM by using a selective packet-discard strategy with tracking of the available buffer space and a packet push-out buffering scheme to accommodate the GFR service. The simulation results show that our proposed method fulfills the requirements of GFR service as well as improves the TCP throughput under the common FIFO scheduling. A feasible implementation approach is also addressed.