摘要:
To eliminate interruption of a service used by a user and reset of communication caused by switching of an operating server such as a process migration or the like. On receiving a session migration start request, server/network cooperation control means 2 issues an operating server-switching control start notification to an operating server switching control means 3 (step S702). On receiving the operating server switching control start notification, the operating server switching control means 3 switches an operating server. Next, on receiving an operating server switching control completion notification, the server/network cooperation control means 2 sends a connection destination target network-switching request to a connection control means 4 (step S707). The connection control means 4 switches the connection destination target network of the user corresponding to a user name whose connection destination target network is to be switched, from a target network including a main server to a switch destination target network including a backup server (step S708).
摘要:
Disclosed is a network system comprising: a plurality of routers 704 and 705 connected to each other through a network; pseudo redundant configuration setting means 702 and 703 which are connected respectively to the routers and which perform a communication using a redundancy protocol with respective routers; and association control means 701 connected to the pseudo redundant configuration setting means 702 and 703, wherein when a server 716 is a backup server and its backup state needs to be maintained, the pseudo redundant configuration setting means 703 issues a signal for maintaining a standby state to the router 705, and when servers are switched between a standby state and operating state, the association control means 701 transmits a switching instruction for switching between a standby state and operating state to the pseudo redundant configuration setting means 702 and 703.
摘要:
Disclosed is a network system comprising: a plurality of routers 704 and 705 connected to each other through a network; pseudo redundant configuration setting means 702 and 703 which are connected respectively to the routers and which perform a communication using a redundancy protocol with respective routers; and association control means 701 connected to the pseudo redundant configuration setting means 702 and 703, wherein when a server 716 is a backup server and its backup state needs to be maintained, the pseudo redundant configuration setting means 703 issues a signal for maintaining a standby state to the router 705, and when servers are switched between a standby state and operating state, the association control means 701 transmits a switching instruction for switching between a standby state and operating state to the pseudo redundant configuration setting means 702 and 703.
摘要:
An optical receiving circuit 1 is composed of a preamplifier circuit 2, an output differential amplifier 3 and a mean value holding circuit 4. The optical receiving circuit 1 is connected to a photodetector 5 for receiving an input optical signal and outputting current. For the preamplifier circuit 2, a transimpedance type circuit may also be used. The preamplifier circuit 2 comprises a feedback resistor 21 and a resistor for detecting output voltage 22, the transimpedance gain is 55 dB &OHgr; and 3 dB bandwidth when the photodetector 5 the capacity of which is 0.2 pF is connected to its output is 8 GHz. The output differential amplifier 3 discriminates and regenerates data by regulating reference voltage Vref between the high level and the low level of the amplitude of an input signal. The mean value holding circuit 4 includes a sample-hold circuit 41 and capacity 42 for holding the mean value of voltage output from the preamplifier circuit 2. As a CR time constant based upon the capacity 42 and the resistor for detection 22 is 1 ns., the mean value level of a received signal can be detected in approximately one byte of the data of 10 Gb/s. The sample-hold circuit 41 samples the detected mean value level according to a sampling pulse from an external device and holds it. The output of the sample-hold circuit 41 is used for the reference voltage of the differential amplifier 3.
摘要:
Disclosed is an optical network which has: wavelength tunable optical transmitters of number MN, where N is an integer of two or more, each of which outputs an optical signal with arbitrary one of M wavelengths &lgr;1, &lgr;2, . . . , &lgr;M, where M is an integer of two or more, that are different from one another; a MN×N optical switch whose input ports are connected to the respective wavelength tunable optical transmitters of number MN, and which allows optical signals input to different input ports to be output form its same output port; 1×M optical wavelength demultiplexers of number N which output demultiplexing optical signal with wavelengths &lgr;1, &lgr;2, . . . , &lgr;M input from output ports of the MN×N optical switch into each wavelength; and optical receivers of number MN which receive optical signals input from the 1×M optical wavelength demultiplexers of number N.
摘要:
A packet switching network which allows the duration of guard time of each packet to be reduced to a minimum and the transmission efficiency of the network to be increased is disclosed. The sending nodes send the packet switch packets each having a guard time added thereto. The receiving nodes receive the packets from the packet switch. Each of the receiving nodes includes a switch timing detector for detecting switch timing of the packet switch based on a serial signal received from the packet switch, and a timing holder for holding the switch timing.
摘要:
An optical packet exchange apparatus and an optical switch in which search for a connection pattern between an input unit devoid of a packet to be transmitted and an output unit devoid of a packet to be received is reduced to enable fast switch control even in cases wherein the number of channels of the exchange apparatus is increased or network speed is higher. A plurality of input units, a plurality of output units and an optical switch are provided. Each input unit includes an input buffer unit, a parallel/serial conversion unit, an electrical/optical conversion unit, and a dummy packet insertion unit for sending a dummy packet if there is no packet to be transmitted. Each output unit includes an exchange counterpart contention resolution unit for controlling the exchange counterpart, an optical/electrical conversion unit, a serial/parallel conversion unit, and a packet eliminating unit. The exchange counterpart contention resolution unit controls the packet eliminating unit to eliminate a dummy packet.
摘要:
An optical cross-connecting device is small in scale of a switch even when a wavelength multiplexed signal to be transmitted through an optical fiber is high density and wide range. Switching of the wavelength multiplexed signals is performed in a first optical switch, switching per wavelength group in a second optical switch is performed for only signals required switching for smaller granularity, and switching per wavelength signals in a third optical switch is performed for only signals required switching for smaller granularity to from the opticall cross-connecting device. By this, even when the wavelength multiplexed signal to be transmitted through the optical fiber is high density and wide band, the optical cross-connecting device can be small in scale of a switch.
摘要:
An optical packet exchange apparatus and an optical switch in which search for a connection pattern between an input unit devoid of a packet to be transmitted and an output unit devoid of a packet to be received is reduced to enable fast switch control even in cases wherein the number of channels of the exchange apparatus is increased or network speed is higher. A plurality of input units, a plurality of output units and an optical switch are provided. Each input unit includes an input buffer unit, a parallel/serial conversion unit, an electrical/optical conversion unit, and a dummy packet insertion unit for sending a dummy packet if there is no packet to be transmitted. Each output unit includes an exchange counterpart contention resolution unit for controlling the exchange counterpart, an optical/electrical conversion unit, a serial/parallel conversion unit, and a packet eliminating unit. The exchange counterpart contention resolution unit controls the packet eliminating unit to eliminate a dummy packet.
摘要:
An optical packet exchange apparatus and an optical switch in which search for a connection pattern between an input unit devoid of a packet to be transmitted and an output unit devoid of a packet to be received is reduced to enable fast switch control even in cases wherein the number of channels of the exchange apparatus is increased or network speed is higher. A plurality of input units, a plurality of output units and an optical switch are provided. Each input unit includes an input buffer unit, a parallel/serial conversion unit, an electrical/optical conversion unit, and a dummy packet insertion unit for sending a dummy packet if there is no packet to be transmitted. Each output unit includes an exchange counterpart contention resolution unit for controlling the exchange counterpart, an optical/electrical conversion unit, a serial/parallel conversion unit, and a packet eliminating unit. The exchange counterpart contention resolution unit controls the packet eliminating unit to eliminate a dummy packet.