The present invention relates to a system and method for dynamic allocation of a resource. In particular, it concerns a system to dynamically designate a priority for a resource request and to allocate a resource, partially filling or completely filling the request. Partial filling of requests and conditional priorities allows maximum use of resources at low priority while protecting minimum access to resources Thus, the system and method of the present invention improve access and optimization of a Bandwidth On Demand (BOD) satellite communication system. Free resources are used as access channelsthat may be allocated to a user.