The increasing interest in dynamic circuit networks to support the high-speed and predictable-service requirements of applications leads to the creation of various experimental test beds. One area of networking research in these testbed projects is bandwidth sharing mechanisms. One reference point for dynamic bandwidth-sharing mechanisms in connection-oriented networks is the telephone network. The bandwidth-sharing mechanism used in the telephone network is referred to as the immediate-request mode because there is no provision for making advance reservations for circuits. While this mechanism can be used in new high-speed optical connection-oriented networks, some applications require high per-call bandwidth, and this bandwidth level is a large fraction of even the highest-rate links in use today, the combination of which makes the immediate-request mode unsuitable. Therefore, alternative bandwidth-sharing modes are needed for these networks and applications. This book discusses two new bandwidth-sharing mechanisms based on book-ahead reservation schemes, and presents both the analytical and simulation models for the two mechanisms.