JP4358162B2 - Gateway device - Google Patents

Description

  The present invention relates to a gateway device used for interconnecting, for example, a circuit switching network and an IP (Internet Protocol) network.

  In recent years, information communication services including voice and data communication have been diversified as information communication needs have increased and communication has been liberalized. Against this background, the number of operators (carriers) newly entering the communication service field is increasing, and service competition among carriers is becoming active. The new carrier is called NCC (New common carrier) and provides various services using a technology such as VoIP (Voice over Internet Protocol). VoIP is a technology that integrates a voice network and a data network by packetizing and transmitting digital voice data.

NCCs often borrow equipment such as an exchange from a specific carrier that already has a subscriber line at a predetermined charge. Many NCCs build their own exchange networks such as IP networks with their own funds. In addition, a communication system is formed by adding a circuit switching network (PSTN: Public Switched Telephone Network) of a specific carrier, and these facilities are used in combination to provide services to general users. The following Patent Document 1 discloses an example of a service using an IP network.
JP 2002-252637 A

  A gateway device is used to construct a communication system that combines a PSTN and an IP network. This type of apparatus includes an IP conversion unit that converts voice data and binary data into IP (Internet Protocol) packets, and a packet switch unit that switches IP packets.

By the way, when a circuit failure or line disconnection occurs in this type of apparatus, the line cannot be used until the card exchange or cable exchange is completed, and it takes time to recover. In order to avoid this, it is conceivable that the IP conversion unit, the packet switch unit, etc. are doubled and the standby system and the active system are switched by a relay for switching the signal path. However, in the existing apparatus, since all traffic is concentrated on the active system, the processing performance may deteriorate.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a network device in which a decrease in performance due to an increase in traffic is reduced.

In order to achieve the above object, according to one aspect of the present invention, a communication protocol is mutually converted between a subscriber network, a circuit switching network, and a packet communication network to realize mutual communication between these networks. A gateway device that terminates the subscriber network and generates an in-device signal; a circuit-switched network interface that terminates the circuit-switched network and generates the in-device signal; and the device Switching means for circuit-switching the internal signal, signal conversion means for packetizing the internal signal output from the switching means to the packet communication network, and the packet signal output from the signal conversion means for the packet communication network A first packet switch that performs route control toward the destination in the first packet switch, a second packet switch that functions as a backup system for the first packet switch, and the first packet switch. A packet signal output from the signal conversion means is input to the second packet switch when a switch switch fails, and a packet signal output from the signal conversion means is input to the first packet switch when there is no failure in the first and second packet switches. And switching means for inputting to the second packet switch, the switching means being provided in the signal input path and the signal output path of the first packet switch and the second packet switch, and the path of the packet signal A plurality of relays that switch between the failure time and the non-failure time, the plurality of relays take two states of on and off, and in the on state, consumes more power than the off state, and the on state In order to make the number of relays equal to the number of relays in the off state and the number of relays in the off state equal to each other at the time of the failure and the time of the no failure, Gateway device is provided, characterized in that connected to the first packet switch and said second packet switch.

By taking such means, the packet switch connected to the packet communication network is made redundant, and the fault tolerance performance is improved. In addition, when there is no failure in the first packet switch as the active system and there is no failure in the second packet switch, the packet traffic is distributed and input to both the first and second packet switches. As a result, it is possible to prevent the traffic from being concentrated on one of the packet switches, and thus it is possible to reduce the performance degradation.
Moreover, the power consumed by the relay can be made substantially the same before and after the redundant switching. Therefore, current consumption can be stabilized before and after redundancy switching, and the burden on the apparatus can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the network apparatus which reduced the performance fall with respect to the increase in traffic can be provided.

[First Embodiment]
FIG. 1 is a system diagram showing an embodiment of a communication system according to the present invention. In FIG. 1, a plurality of subscriber lines 114 of the subscriber network SN are first accommodated in the gateway device 1. The gateway device 1 is connected to the IP network DN. The IP network DN is a packet communication network, and is formed as an NCC original network. The Internet can also be connected as the IP network DN.

  The subscriber network SN includes a subscriber terminal 5, a mobile phone system base station CS1, and a radio terminal PS1. The subscriber terminal 5 and the base station CS1 are connected to the gateway device 1 via the subscriber line 114. The subscriber line 114 is an access line assigned to each of the plurality of subscriber terminals 5 and the wireless terminal PS1.

  The gateway device 1 sends a signal (digital data signal such as voice data, video, and image data) generated from the subscriber network SN to the IP network DN. Further, the gateway device 1 sends a signal addressed to the terminal in the subscriber network SN from the IP network DN into the subscriber network SN and causes the terminal to receive the signal. Thereby, a bidirectional communication path can be arbitrarily set between the subscriber terminal 7 belonging to the IP network DN, the subscriber terminal 5 and the wireless terminal PS1. Further, in the system of FIG. 1, a network monitoring device ME is provided in the IP network DN. The network monitoring device ME exchanges various information with the gateway device 1 via the IP network DN, and mainly manages the operation state of the gateway device 1.

  FIG. 2 is a system block diagram showing an existing voice communication system. In FIG. 2, the subscriber terminal 5 of the subscriber network SN is accommodated via the subscriber line 114 in the exchange 3 of the circuit switched network XN. The exchange 3 is a facility belonging to the circuit switching network XN. When the system of FIG. 1 and the system of FIG. 2 are combined, the gateway device 1 is provided on the subscriber terminal side with respect to the exchange 3. Therefore, the connection point between the subscriber network SN and the circuit switching network XN is a connection point between the gateway device 1 and the exchange 3. That is, the gateway device 1 is arranged on the subscriber network SN side from the connection point between the network of the subscriber network SN and the circuit switching network XN. Further, the communication protocols of the subscriber network SN, the circuit switching network XN, and the IP network DN are different from each other.

  FIG. 3 is a functional block diagram showing an embodiment of the gateway device 1 of FIG. In FIG. 3, the gateway device 1 includes a control unit 16 and subscriber line interfaces 11 and 12. The subscriber line interface 11 performs interface control of the subscriber line 114, and the subscriber line interface 12 performs interface control of the subscriber line 115.

  That is, the subscriber line interface 11 accommodates subscriber terminals and radio base stations via the subscriber line 114, and provides an exchange side interface for ISDN (Integrated Service Digital Network). The subscriber line interface 12 is connected to the subscriber line 115 and provides a terminal side interface of ISDN. The communication capacity of the subscriber line 115 is designed in advance based on traffic demand prediction.

  The control unit 16 includes an exchange unit 100 such as a time division switch. The exchange unit 100 exchanges and connects communication paths between the IP network DN and each of the subscriber lines 114. When the circuit switching network XN is connected to the gateway device 1, the switching unit 100 switches and connects the communication paths between the circuit switching network XN and the IP network DN and each of the subscriber lines 114.

  Further, the gateway device 1 of FIG. 3 includes an IP conversion unit 14 and a packet switch 15. The IP conversion unit 14 is provided between the control unit 16 and the IP network DN, and performs protocol conversion between networks. That is, the IP conversion unit 14 converts a time division multiplexed signal given through another communication network (such as a circuit switching network XN) into an IP packet and inputs it to the packet switch 15. The IP packet is routed according to the destination IP address, and is sent to the IP network DN via a LAN (Local Area Network) cable 117. The IP converter 14 converts an IP packet input from the IP network DN via the LAN cable 117 and the packet switch 15 into a time division multiplexed signal.

  In FIG. 3, the number of subscriber lines 114 accommodated in the subscriber line interface 11 is equal to the number of subscriber lines 115 accommodated in the subscriber line interface 12, that is, the communication capacity. . Alternatively, the number of subscriber lines 114 accommodated in the subscriber line interface 11 is made larger than the number of subscriber lines 115 accommodated in the subscriber line interface 12. This is advantageous in terms of system design.

  The control unit 16 performs overall control of the gateway device 1. That is, the control unit 16 requests the subscriber line interface 11 and the subscriber line interface 12 to control the subscriber line 114 and the subscriber line 115, and the subscriber line interface 11 and the subscriber line interface 12 Comprehensively manage detected failures.

  The control unit 16 of the gateway device 1 is connected to the network monitoring device ME via the IP network DN. The network monitoring device ME communicates with the control unit 16 and displays the information managed comprehensively on the network monitoring device ME side, whereby the gateway device 1 can be remotely monitored and managed.

  In FIG. 3, the control unit 16 is connected to the IP network DN via the IP conversion unit 14 and the packet switch 15. Each of the subscriber line interfaces 11 and 12 and the control unit 16 includes a dedicated CPU (Central Processing Unit) and a memory (not shown), and operates by CPU arithmetic processing based on a program stored in each memory.

  FIG. 4 is a block diagram showing a redundant configuration of the control unit 16 and the packet switch 15 of FIG. Both the control unit 16 and the packet switch 15 are duplexed into an active system and a standby system. The packet switch 15 is duplicated into an active LAN switch 151 and a standby LAN switch 152. The control unit 16 is duplicated into an active system control unit 16a and a standby system control unit 16b. The active LAN switch 151 and the standby LAN switch 152 respectively notify the active system control unit 16a and the standby system control unit 16b of a status signal indicating their own driving state in response to a polling request or the like. The control unit 16 recognizes the driving state of the packet switch 15 and gives a control signal based on the result to the relay control circuit 159. The relay control circuit 159 outputs a relay control signal for switching and controlling a plurality of relays (described later) provided in the packet switch 15 based on the drive states of the active LAN switch 151 and the standby LAN switch 152. .

  FIG. 5 is a functional block diagram showing a main configuration of the packet switch unit 15 of FIG. The packet switch unit 15 is realized as, for example, a switching IC (Integrated Circuit), and includes a LAN switch that processes IP packets in the OSI reference model third layer and below. The LAN switch is duplexed with an active system and a standby system, and reference numeral 151 is assigned to the active LAN switch and reference numeral 152 is assigned to the standby LAN switch.

  Further, the packet switch unit 15 switches the transmission path of the IP packet transmitted via the serial bus 116 to either the active LAN switch 151 or the standby LAN switch 152, and the active LAN switch 151 and the standby LAN switch 152. Are provided with relays 153 to 158 for realizing redundant switching. Relays 153 to 158 each have two contacts, and one contact is connected in the on state, and the other contact is connected in the off state. Power is consumed in any state, but it is assumed that the power consumption in the on state is larger than that in the off state. Each of the relays 153 to 158 is switched to an on or off state by relay control signals 1510 and 1511 provided from the relay control circuit 159.

  In FIG. 5, the serial bus 116 from the IP conversion unit 14 is branched into two systems and connected to the input terminals of the relays 153 and 154, respectively. The off-side terminal of the relay 153 and the on-side terminal of the relay 154 are connected to the active LAN switch 151, and the on-side terminal of the relay 153 and the off-side terminal of the relay 154 are connected to the standby LAN switch 152.

  The output of the active LAN switch 151 is connected to the input terminal of the relay 155, and the output of the standby LAN switch 152 is connected to the input terminal of the relay 157. The off-side output terminal of relay 155 is connected to the off-side input terminal of relay 156. The ON-side output terminal of relay 155 is connected to the ON-side input terminal of relay 158. The ON side output terminal of the relay 157 is connected to the ON side input terminal of the relay 156. The off-side output terminal of the relay 157 is connected to the off-side input terminal of the relay 158. The output terminal of the relay 156 is connected to the working port 1512, and the output terminal of the relay 158 is connected to the spare port 1513. The working port 1512 and the spare port 1513 are connected to the IP network DN via the LAN cable 117.

  FIG. 6 is a diagram showing signal paths in the normal state of the packet switch unit 15 in FIG. In FIG. 6, in a normal state, that is, when there is no failure, the relay 153 is turned off and the relay 154 is turned on, and all IP packets from the serial bus 116 are connected to the working LAN switch 151. Also, the relays 155 to 158 are turned off, and the active LAN switch 151 is connected to the IP network DN via the active port 1512 and the LAN cable 117.

  FIG. 7 is a diagram showing signal paths when a failure occurs in the active LAN switch 151 from the state shown in FIG. When a failure occurs in the active LAN switch 151, the status signal from the active LAN switch 151 in FIG. 4 is given to the active system controller 16a. As a result, the active control unit 16a recognizes the occurrence of the failure and issues relay control information to the relay control circuit 159. In response, relay 153 is turned on by relay control signal 1510 and relay 154 is turned off. As a result, all IP packets from the serial bus 116 are connected to the backup LAN switch 152. Further, the relays 156 and 157 are both turned on by the relay control signal 1511, whereby the backup LAN switch 152 is connected to the IP network DN via the working port 1512.

  FIG. 8 is a diagram showing a signal path when a line failure occurs in the working port 1512 from the state shown in FIG. When a line failure occurs in the working port 1512, the working LAN switch 151 connected to the working port 1512 detects the failure, and the status signal from the working LAN switch 151 in FIG. 4 is given to the working control unit 16a. . As a result, the active control unit 16a recognizes the occurrence of the failure and issues relay control information to the relay control circuit 159. In response to this, the relay 153 is turned off and the relay 154 is turned on, whereby all IP packets from the serial bus 116 are connected to the working LAN switch 151. Also, the relays 156 and 157 are both turned on by the relay control signal 1511, whereby the working LAN switch 151 is connected to the IP network DN via the spare port 1513.

  As described above, in the present embodiment, the packet switch unit 15 includes the active LAN switch 151 and the standby LAN switch 152 for redundancy, and is provided in the signal input path and the signal output path of each of the LAN switches 151 and 152. Redundancy switching can be performed by relays 153 to 158. As a result, a quick recovery from a failure can be realized. Each of the relays 153 to 158 has two connection states of off and on, and it is assumed that a large amount of power is consumed in the on state. The relays 153 to 158 are connected to the active LAN switch 151 and the standby LAN switch 152 so that the number of relays in the on state is the same before and after the redundant switching, that is, during normal operation and during failure operation. Like to do.

  In the existing apparatus, for example, all the relays are turned off during the active system operation, and all the relays are turned on when switching to the standby system. Since relays consume a relatively large amount of power in the on state, the power consumption increases rapidly when all relays are turned on, and there is a risk of overloading the power supply circuit, etc., leading to equipment damage in the worst case. There is.

  On the other hand, in the first embodiment, the driving direction of the relays (relays 153 and 154) connected to the IP conversion unit 14 is reversed by half, so the number of driving relays in the state of FIG. Assuming n, the number of driving relays in the state of FIG. 7 is n + 2, and the number of driving relays in the state of FIG. 8 is n + 2. Therefore, the number of relays in the driving state (ON state) before and after the redundant switching is almost the same. Therefore, the current consumption can be stabilized before and after the redundant switching, and the burden on the power supply circuit and the like can be reduced. In particular, this effect becomes more remarkable as n increases. From the above, it is possible to provide a gateway device that can stabilize power consumption and can quickly recover from a failure.

[Second Embodiment]
Each of the relays 153 to 158 can be individually turned on / off, and the combination of the on / off states of each relay is not limited to the above. In the following, an embodiment capable of reducing the load on the LAN switch by taking advantage of the provision of the active system and the standby system will be disclosed.

  FIG. 9 is a diagram illustrating another example of a signal path in the packet switch unit 15 of FIG. In FIG. 9, it is assumed that no failure has occurred in either the active LAN switch 151 or the standby LAN switch 152. This is recognized by the control unit 16 in FIG. In this state, the control unit 16 turns off all the relays 153 to 158. By doing so, the traffic load of the LAN switches 151 and 152 can be distributed. Further, when the IP conversion unit 14 is made redundant, the traffic load of each IP conversion unit 14 can be reduced. As a result, concentration of traffic can be prevented, and the load can be distributed to reduce performance degradation. In addition, since all the relays 153 to 158 are in the off state in this state, the power consumption is also minimum.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

1 is a system diagram showing an embodiment of a communication system according to the present invention. The system block diagram which shows the existing audio | voice communication system. The functional block diagram which shows embodiment of the gateway apparatus 1 of FIG. FIG. 4 is a block diagram showing a redundant configuration of a control unit 16 and a packet switch 15 in FIG. 3. The functional block diagram which shows the principal part structure of the packet switch part 15 of FIG. The figure which shows the signal path | route in the normal state of the packet switch part 15 of FIG. FIG. 7 is a diagram showing a signal path when a failure occurs in the active LAN switch 151 from the state shown in FIG. 6. FIG. 7 is a diagram showing a signal path when a line failure occurs in the working port 1512 from the state shown in FIG. 6. The figure which shows the other example of the signal path | route in the packet switch part 15 of FIG.

Explanation of symbols

  SN ... subscriber network, DN ... IP network, XN ... circuit switching network, 1 ... gateway device, CS1 ... base station, PS1 ... wireless terminal, 3 ... exchange, 5-7 ... subscriber terminal, 11 ... subscriber line interface (Terminal side), 12 ... subscriber line interface (switch side), 14 ... IP conversion unit, 15 ... packet switch unit, 16 ... control unit, 114 ... subscriber line, 115 ... subscriber line, 116 ... serial bus, 117: LAN cable, 151 ... active LAN switch, 152 ... standby LAN switch, 153 to 158 ... relay, 159 ... relay control circuit, 1512 ... active port, 1513 ... spare port

Claims (2)

A gateway device that converts communication protocols between a subscriber network, a circuit switching network, and a packet communication network to realize mutual communication between these networks,
A subscriber network interface that terminates the subscriber network and generates an in-device signal;
A circuit switching network interface that terminates the circuit switching network and generates the in-device signal;
Switching means for circuit-switching the in-device signal;
A signal conversion means for packetizing the in-device signal output from the switching means toward the packet communication network;
A first packet switch for routing the packet signal output from the signal conversion means toward the destination in the packet communication network and sending out the packet signal;
A second packet switch functioning as a backup system for the first packet switch;
A packet signal output from the signal conversion means when the first packet switch fails is input to the second packet switch, and a packet signal output from the signal conversion means when the first and second packet switches do not fail Switching means for inputting to the first and second packet switches ,
This switching means is
A plurality of relays that are provided in signal entry paths of the first packet switch and the second packet switch, and switch the path of the packet signal between the failure time and the no-failure time;
These relays take two states, on and off, and consume more power in the on state than in the off state,
The plurality of relays are connected to the first packet switch and the second packet switch so that the number of relays in the on state and the number of relays in the off state are equivalent to each other at the time of the failure and at the time of the no failure. A gateway device characterized by that. The plurality of relays are provided in a signal input path and a signal output path of the first packet switch and the second packet switch,
A first port for sending a packet signal sent from the first packet switch or the second packet switch to the packet communication network;
The gateway device according to claim 1, further comprising a second port functioning as a standby system for the first port.

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