Fujitsu Corporation

Yuichiro Chikamatsu

Hideo Abe

Yasuo Tezuka

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.

Edge switch

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.

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Kawasaki, Japan

Yuichiro Chikamatsu