The objective of this work was to investigate performance issues in a video conference system on an FDDI network under a PC DOS environment. According to the real problems identified through the system prototyping, we propose solutions to improve the system performance. We design a network interface architecture to minimize the CPU waiting time during the handshaking process, and derive a synchronous bandwidth reservation method to guarantee the delay-jitters of video frame transmissions. Our method is proven to fulfill the FDDI requirement.