The present invention provides for a method that could be advantageously implemented in a satellite local area network (LAN) in which an average number of sites share a TDMA link. The invention provides for both a dedicated bandwidth to all the sites and a shared bandwidth that is dynamically assigned to the sites, therefore allowing for both synchronous traffic and for on request burst mode traffic. The method includes a reservation method of this shared bandwidth which is specially optimized for a satellite link. The method provides also for a network that automatically managed its communication bandwidth resources and the synchronization of the sites, without the need of an external controller. The present invention also provides for a satellite modem to transmit data from a site, to receive data from the sites and to manage the bandwidth resources of the TDMA satellite in accordance with the above method.