Abstract: An edge switch comprises a token bucket control unit which varies the amount of tokens flowing into a token bucket per unit time in accordance with the congestion condition of an IP network, and the output rate of packets to be output onto a packet communication network is adjusted for each line identifier by controlling the output amount of a packet buffer, in accordance with the amount of tokens held in the token bucket; and, an analyzing unit that determines whether the source address of the received packet matches the address of a preregistered emergency call destination, and the token bucket control unit further reduces, when an emergency call is generated, the amount of tokens flowing into the token bucket for any destination address in congestion, other than the emergency call destination, and thereby retaining communication quality for emergency priority communication.

Abstract: An edge switch comprises a token bucket control unit (234) which varies the amount of tokens flowing into a token bucket (233) per unit time in accordance with the congestion condition of an IP network, and the output rate of packets to be output onto a packet communication network is adjusted for each line identifier by controlling the output amount of a packet buffer, which defines the output rate of the packets to be output onto the IP network, in accordance with the amount of tokens held in the token bucket; on the other hand, a packet analyzing unit (239) comprises means for determining whether the source address of the received packet matches the address of a preregistered emergency call destination, and the token bucket control unit comprises means for further reducing, upon detection of a call initiated from an emergency call destination, the amount of tokens flowing into the token bucket for any destination address, other than the emergency call destination, that is experiencing congestion, and there

Abstract: A communication unit which transmits packets in the form of ATM cells, includes a packet buffer part receiving Virtual Channel (VC)-multiplexed ATM cells from an input line, judging a packet type, converting a header and assembling a packet, a protocol processing part receiving and processing a protocol packet output from the packet buffer part when the packet type of the packet assembled in the packet buffer part is the protocol packet which is used for communication control, and a packet output scheduling part, including a scheduler which carries out an arbitration when an output request generated upon completion of a reception of a user packet from the packet buffer part and an output request generated upon ending of a process from the protocol processing part are received, and selects and outputs to an output line the user packet or the protocol packet based on the arbitration.

Abstract: In a gateway apparatus which interconnects a first network and a second network, an encoding processing unit receives voice data from the first network and generates encoded voice data from the received voice data. A packet processing unit creates packets of the encoded voice data and transmits the packets to the second network. A network-state estimation unit determines network-state information of the second network. A determination unit controls at least one of the encoding of the encoding processing unit and the packetizing of the packet processing unit based on the network-state information determined by the network-state estimation unit.