Patent ID: 7239637
Filing Date: 2007-07-03
Classification: H04L

Abstract:
1. A packet communication system in which a plurality of terminal side devices are connected to a network side device through a shared transmission medium, said network side device allocates time slots to identifier assigning objects accommodated in each of said respective terminal side devices and the respective identifier assigning objects transfer packets through a physical medium by using the time slots allocated thereto, wherein said network side device comprising: identifier assigning means for assigning identifiers for identifying time slots allocated to said respective identifier assigning objects accommodated in each of said terminal side devices and notifying said respective identifier assigning objects of the assigned identifier; and time slot allocating means for allocating time slots to said respective identifier assigning objects accommodated in each of said terminal side devices, describing the identifiers assigned to said identifier assigning objects in the time slots and notifying said objects of the identifiers, each of said terminal side devices comprising: buffer means for storing packets inputted from a plurality of terminals connected to said terminal side device in every identifier assigning object; output control means for holding identifiers assigned to said respective identifier assigning objects accommodated in each of said terminal side devices according to a notice content notified by said identifier assigning means of said network side device and, when the identifiers described in the time slots notified by said time slot allocating means are coincident with the identifiers assigned to said identifier assigning objects accommodated in each of said terminal side devices, outputting packets from said buffer means corresponding to said identifier assigning objects; and identifier control means for transmitting an identifier assigning request for requesting an assignment of identifier to identifier assigning objects to which identifiers are not assigned to said network side device, said identifier assigning means comprising: dynamic assigning means for changing a state of an identifier from an assigned state to a non-assigned state by performing an identifier releasing processing for the identifier on demand, selecting any one of the identifiers and assigning the selected identifier to said identifier assigning object from which the identifier assignment request is transmitted, when an identifier assigning request is received from said identifier control means and there is one or more identifiers in the non-assigned state, wherein said dynamic assigning means selects an object whose identifier is to be released, according to a preset priority order for releasing said respective identifier assigning objects accommodated in each of said terminal side devices; and notice means for notifying the object from which the identifier assignment request is transmitted when the identifier releasing processing is performed, a new identifier is assigned and no identifier in the non-assigned state exists for the identifier assigning request.