Abstract: A gateway unit which relays communication between a call control network and a terminal having no call control function. The gateway unit includes: a session control section which substitutively performs call control processing in call control communication performed by the terminal by way of the call control network and reports a band required for the call control communication to the call control network; and a band adjustment section which determines an updated value of a band of the call control communication based on a communication packet in the call control communication, received from the terminal. The session control section reports the updated value to the call control network as the band required by the call control communication.

Abstract: A communication control method performing Discovery processing, which is a procedure at an OLT to detect an ONU newly connected, in a PON system, the method includes: a transmission-permission-signal transmitting step of transmitting, by the OLT, a transmission permission signal for discovery, which includes an individual number of an ONU that is permitted to respond and mask information for designating a match-detection target bit for the individual number; and a registration-request-signal transmitting step of comparing, by an ONU, which is not registered in the OLT, a match-detection target bit for the individual number designated in the mask information with an individual number of the ONU based on a received transmission permission signal, and when the target bit and the individual number match each other, transmitting a registration request signal to the OLT.

Abstract: Provided is an optical access network capable of realizing protection control without affecting an E-PON for providing an Ethernet service. In the optical access network comprising the E-PON having a transmission line which is duplexed between an OLT and a plurality of ONTs, the OLT includes a layer-2 (L2) control section in which a protocol, in which protection control information is provided, as a protocol structure, above an Ethernet media access control (MAC), is mounted. Further, the OLT has a protocol structure in which the protection control information is provided independently from the Ethernet MAC to transfer user data and the protection control information.

Abstract: A gateway unit which relays communication between a call control network and a terminal having no call control function. The gateway unit includes: a session control section which substitutively performs call control processing in call control communication performed by the terminal by way of the call control network and reports a band required for the call control communication to the call control network; and a band adjustment section which determines an updated value of a band of the call control communication based on a communication packet in the call control communication, received from the terminal. The session control section reports the updated value to the call control network as the band required by the call control communication.

Abstract: A communication control method performing Discovery processing, which is a procedure at an OLT to detect an ONU newly connected, in a PON system, the method includes: a transmission-permission-signal transmitting step of transmitting, by the OLT, a transmission permission signal for discovery, which includes an individual number of an ONU that is permitted to respond and mask information for designating a match-detection target bit for the individual number; and a registration-request-signal transmitting step of comparing, by an ONU, which is not registered in the OLT, a match-detection target bit for the individual number designated in the mask information with an individual number of the ONU based on a received transmission permission signal, and when the target bit and the individual number match each other, transmitting a registration request signal to the OLT.

Abstract: A bandwidth guaranteed communication system is obtained for securing or reserving a bandwidth dynamically required for a minute unit such as an application on Ethernet. The system is provided with a communication network in which a plurality of devices each terminating a layer 2 are arranged. At the time of bandwidth reservation, a bandwidth reservation request is made through an Ethernet OAM frame from an end point performing the bandwidth reservation by the use of the Ethernet OAM frame specified by the layer 2. It is determined by an intermediary one of the plurality of devices whether the bandwidth reservation can be made. If the bandwidth reservation can be made, the bandwidth reservation is transmitted to a device in a downstream direction, and when it reaches the most distant point, the bandwidth reservation request is returned to a transmitting source, whereby it is recognized that the bandwidth reservation has been completed and the start of user communication is permitted.

Abstract: Provided is an optical access network capable of realizing protection control without affecting an E-PON for providing an Ethernet service. In the optical access network comprising the E-PON having a transmission line which is duplexed between an OLT and a plurality of ONTs, the OLT includes a layer-2 (L2) control section in which a protocol, in which protection control information is provided, as a protocol structure, above an Ethernet media access control (MAC), is mounted. Further, the OLT has a protocol structure in which the protection control information is provided independently from the Ethernet MAC to transfer user data and the protection control information.

Abstract: An optical communication system connects one to a plurality subscriber-side apparatuses having one to a plurality of subscriber terminals and a station-side apparatus that covers the subscriber-side apparatuses with an optical transmission medium, sets one to a plurality of logical links between the station-side apparatus and each subscriber-side apparatus, and performs a data transfer with an MAC frame using a set logical link. The station-side apparatus and the subscriber-side apparatus transmit control information of a plurality of set logical links by storing the control information in a single MAC frame.

Abstract: A communication network includes a plurality of user networks that accommodates IP terminals and does not perform a call control function, a core network (a call control network) that is located among the user networks and performs a call control function and a call management function, and a gateway that connects the user networks to the core network. The gateway receives a communication request packet from the user network or a data packet that is initially transmitted, and analyzes the packet. Thus, the gateway establishes a necessary call in the core network to allow an IP packet to pass through the core network.

Abstract: Dynamic up-link bandwidth allocation is realized in a optical communication system in which a plurality of subscriber devices with mutually different device configurations are connected to a station unit, by configuring the station unit to consider device configurations of the subscriber devices in performing up-link bandwidth allocation.

Abstract: In a communications system in which a plurality of subscriber apparatuses and a station apparatus are connected to the same transmission channel for bidirectional communication, a bandwidth allocated in a direction from subscriber apparatuses to a station apparatus is dynamically updated. More specifically, a bandwidth usage rate is calculated from a bandwidth allocated in a updating period and a bandwidth actually used in the updating period. A bandwidth to be allocated in a subsequent period is determined based on the bandwidth usage rate thus calculated. With this construction, the station apparatus is capable of allocating the bandwidth required by the subscriber apparatuses or subscriber terminal apparatuses so that the bandwidth is efficiently used.

Abstract: A dynamic bandwidth assignment system includes a network unit for carrying out cell slot assignment, and a network termination for transmitting cells to the network unit by means of cell slots assigned by the network unit. When the number of consecutive valid cells the network unit receives from the network terminations exceeds a predetermined threshold value, the network unit increases the number of the cell slots to be assigned to the network termination. The system can solve a problem of a conventional system in that it is unavoidable that a cell transfer delay and a bursting tendency of cells are statistically increased.

Abstract: A dynamic bandwidth assignment system includes a network unit for carrying out cell slot assignment, and a network termination for transmitting cells to the network unit by means of cell slots assigned by the network unit. When the number of consecutive valid cells the network unit receives from the network terminations exceeds a predetermined threshold value, the network unit increases the number of the cell slots to be assigned to the network termination. The system can solve a problem of a conventional system in that it is unavoidable that a cell transfer delay and a bursting tendency of cells are statistically increased.

Abstract: In a communications system in which a plurality of subscriber apparatuses and a station apparatus are connected to the same transmission channel for bidirectional communication, a bandwidth allocated in a direction from subscriber apparatuses to a station apparatus is dynamically updated. More specifically, a bandwidth usage rate is calculated from a bandwidth allocated in a updating period and a bandwidth actually used in the updating period. A bandwidth to be allocated in a subsequent period is determined based on the bandwidth usage rate thus calculated. With this construction, the station apparatus is capable of allocating the bandwidth required by the subscriber apparatuses or subscriber terminal apparatuses so that the bandwidth is efficiently used.

Abstract: Dynamic up-link bandwidth allocation is realized in a optical communication system in which a plurality of subscriber devices with mutually different device configurations are connected to a station unit, by configuring the station unit to consider device configurations of the subscriber devices in performing up-link bandwidth allocation.

Abstract: An optical line terminal in an ATM based passive optical network (APON; ATM-PON) system in which dynamic bandwidth assignment is performed between the optical line terminal and an optical network terminal, including a shaper unit for shaping cells from the optical network terminal and a usage parameter control for monitoring the traffic of the cells shaped by the shaper unit.

Abstract: Slave stations (20-1-20-3) detect whether the buffer resident quantity in a buffer (25) is equal to or larger than a predetermined threshold. Each slave station comprises a buffer resident detection section (26) for notifying the detected results to a PT changing section (24). The PT changing section (24) changes the PT's in the ATM headers of the ATM cells which have been read out from the buffer (25) when there is a notification from the buffer resident detection section (26) that the buffer quantities are equal to or larger than the predetermined threshold.

Abstract: A dynamic bandwidth assignment system includes a network unit for carrying out cell slot assignment, and a network termination for transmitting cells to the network unit by means of cell slots assigned by the network unit. When the number of consecutive valid cells the network unit receives from the network terminations exceeds a predetermined threshold value, the network unit increases the number of the cell slots to be assigned to the network termination. The system can solve a problem of a conventional system in that it is unavoidable that a cell transfer delay and a bursting tendency of cells are statistically increased.

Abstract: A multicast connection control apparatus provided in a branching-and-consolidating node connecting a source terminal to a plurality of destination terminals for branching information over the forward connection or consolidating information over the backward connection in a multicast connection ATM network system includes a congested status management table for managing congested status in all RM cells and a controller. The controller transmits only an uncongested status RM cell transmitted thereto last over the backward connection when all the connections in a sequence are found to be in the uncongested state. The controller also transmits only a congested status RM cell over the backward connection when one of the connections is found to be in the congested state and cancels the subsequent transmission of the congested status RM cells in the same sequence over the backward connection.

Abstract: An asynchronous transfer mode (ATM) communication network system is constructed by connecting a plurality of ATM terminal communication devices to each other through connections. Each ATM terminal communication device has a transmission function to transmit an output ATM cell and a receiving function to receive an input ATM cell.