JP4393410B2 - Communications system - Google Patents

Description

  The present invention relates to a communication system formed by interconnecting, for example, a circuit switching network and an IP (Internet Protocol) network. In order to form this type of system, for example, a communication device such as a gateway device or FEP (Front End Processor) is used.

  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 for providing services to general users.

  In order to interconnect different communication networks such as PSTN and IP network, network connection devices such as a gateway device and FEP are used. By providing a plurality of these devices in the system so that a detour route can be set in the event of a device failure, the fault tolerance performance can be improved.

  In the conventional system, the connection destination is fixedly determined for each of a plurality of ports, and only about one redundant path is secured. On the other hand, in recent years, a plurality of network connection devices are positioned as a source device and a destination device so that communication with each other is always started from the source device. Communication is performed. In this way, n-1 detour destinations are always ensured for the m source devices, and the reliability can be improved.

In addition to forming a redundant system in the system, distributing the communication load is also effective for improving the reliability of the communication system. For example, Patent Document 1 below discloses an example of a load distribution technique in a communication system. This document discloses a relay apparatus that improves the processing speed by eliminating the need to look up (look up) the load distribution table for each communication frame.
Japanese Patent Laid-Open No. 11-122246

  By the way, in a system that realizes redundancy by causing m to n communication to be performed by a plurality of originating devices and terminating devices, when a failure occurs in the terminating device, the failure propagates to other terminating devices. System down. That is, when communication with one of the destination devices becomes impossible, the source device selects another destination device as a detour destination. At this time, if the logic of simply selecting the next destination device is employed, the same destination device is selected from a plurality of source devices. Therefore, the load further added to the load housed in the faulty destination device is concentrated on the next destination device, and the next destination device is also down.

  In an existing system, such a phenomenon may occur in a chain, and this possibility is very high particularly when the number of ports on the calling side is larger than that on the called side. When such a situation occurs, all the receiving side devices become avalanche-type obstacles, and a system down is inevitable.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a communication system that can prevent a failure from being propagated in a chain due to load concentration, thereby improving reliability. .

In order to achieve the above object, according to one aspect of the present invention, a communication network and a plurality of communication devices that perform many-to-many communication via the communication network, the plurality of communication devices include: A plurality of called-side devices each uniquely having address information that can be defined by distinguishable numerical values, and a plurality of calling-side devices that connect to one called-side device based on the address information and actively start the communication In the communication system positioned at any one of the devices , each of the plurality of communication devices that are the originating device associates the address information of each of the plurality of called devices with the state of the called device. A list of addresses, a selection means for selecting a destination device to be connected based on the contents of the address list, and a destination device selected by the selection means. A communication means for starting the communication by connecting to the communication means, and a determination means for determining the state of the called-side apparatus related to the communication from the state of the communication started by the communication means, and the selection means comprises the connection The determination means includes a process for selecting a destination apparatus to be connected in ascending order of numerical values corresponding to the address information and a process for selecting the destination apparatus to be connected in an old numerical order corresponding to the address information. Thus, there is provided a communication system that is alternately implemented every time a called-side device determined to be not normal is generated.

  By taking such means, at the start of communication, first the destination device to be connected to its own device is selected in accordance with the address list AL in each originating device, and communication to the selected destination device is started. The When a failure occurs in any destination device from the state in which communication is continued, that fact is determined in the originating device, and the process for selecting the next connection destination is resumed by the selection means. When the connection unit is reset, for example, first, each destination device is sequentially assigned to each source device in ascending order of address information. Then, when a failure occurs next, each destination device is sequentially assigned to each source device in the order of oldest address information. In this way, the selection process in the order of younger numbers and the selection process in the order of older numbers are performed alternately. As a result, the connection destinations from the calling side device are equally distributed to a plurality of normal called side devices. Therefore, it is possible to prevent a load from being concentrated on one destination device, and it is possible to improve reliability by preventing a failure from being propagated in a chain.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to prevent that a failure propagates in a chain due to load concentration, thereby providing a communication system with improved reliability.

  FIG. 1 is a system diagram showing an embodiment of a communication system in which a gateway device according to the present invention is used. 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 subscriber network SN includes a subscriber terminal 5, a mobile phone system base station CS1, a radio terminal PS1, and the like. The subscriber terminal 5 and the base station CS1 are connected to the gateway device 1 via a subscriber line. The subscriber line 114 is an access line assigned to each of the plurality of subscriber terminals 5 and the wireless terminal PS1.

  The IP network DN includes an FEP server 8, and the FEP server 8 is connected to the Internet via a router 9. The router 9 may be connected to an access server (AS) connected to a circuit switching network or the like. Furthermore, a network management device ME is provided in the IP network DN. The network management device ME exchanges information with the gateway device 1 via the IP network DN, and mainly manages the operation state of the gateway device 1.

  The subscriber network SN includes a subscriber terminal 5, a base station CS1 of a mobile telephone system, and a wireless terminal PS1 such as a PHS (Personal Handy-phone System). 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.

  FIG. 2 is a system 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.

  It is also possible to combine the systems of FIG. 1 and FIG. In this case, the gateway device 1 is provided closer to the subscriber terminal than 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.

  In such a system configuration, the gateway device 1 distributes a signal (digital data signal such as voice data, video, and image data) transmitted from the subscriber network SN to either the exchange 3 or the IP network DN and sends it out. To do. Further, the gateway device 1 sends a signal addressed to the terminal in the subscriber network SN from the exchange 3 and 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 6 belonging to the circuit switching network XN, the subscriber terminal 7 belonging to the IP network DN, the subscriber terminal 5 and the radio terminal PS1. it can. A gateway device 1 that accommodates the subscriber terminal 7 may be provided. Also in this case, the gateway device 1 is connected to the exchange 3 of the circuit switching network XN. Next, a more detailed embodiment of the present invention will be described in two cases.

[First Embodiment]
In this embodiment, a technique capable of appropriately allocating a plurality of destination devices among a plurality of originating devices will be described.

  FIG. 3 is a conceptual diagram showing a communication system according to the first embodiment of the present invention. In FIG. 1, the communication network NET includes the circuit switching network XN and the IP network DN of FIG. A plurality of calling side devices T1 to Tm and a plurality of called side devices R1 to Rn are connected to the communication network NET. The originating devices T1 to Tm are, for example, the gateway device 1 in FIG. 1, and the terminating devices R1 to Rn are, for example, the FEP 8 in FIG. Note that the originating devices T1 to Tm and the terminating devices R1 to Rn do not necessarily have to be a single device casing, and may be, for example, a plurality of ports provided in one device, or software objects that communicate with each other. It may be. In FIG. 3, it is preferable in terms of system design to increase the number (n) of destination devices R1 to Rn rather than the number (m) of source devices T1 to Tm.

  In FIG. 3, the originating side devices T1 to Tm and the terminating side devices R1 to Rn perform m-to-n communication, that is, many-to-many communication via the communication network NET. The called-side devices R1 to Rn have their own addresses (for example, IP addresses) that can be defined by distinguishable numerical values. The originating side devices T1 to Tm connect to one destination side device based on the address information, and actively start communication with the destination side destination device. That is, communication is always started from the originating devices T1 to Tm.

  FIG. 4 is a functional block diagram showing the main configuration of the originating devices T1 to Tm in FIG. That is, FIG. 4 shows the configuration of the gateway device 1 when the gateway device 1 is applied as the originating devices T1 to Tm.

  In the gateway device 1 shown in FIG. 4, the control unit 16 is connected to the communication network NET via the transmission port 14a. The transmission port 14a is, for example, the IP line control units 208 and 209 in FIG. The gateway device 1 stores the address list AL in the storage unit M such as a semiconductor memory. The address list AL is a database in which the addresses of the destination side devices R1 to Rn are associated with the status of each destination side device in a table form.

  The control unit 16 further includes a selection processing unit 16a, a communication processing unit 16b, and a determination processing unit 16c as processing functions according to the present embodiment. The selection processing unit 16a selects a destination device to be connected in the system of FIG. 3 based on the contents of the address list AL. The communication processing unit 16b is connected to the destination device selected by the selection processing unit 16a and starts communication with the connected destination device. The determination processing unit 16c monitors the state of communication started by the communication processing unit 16b, and determines the state of the destination device related to the communication.

  In particular, the selection processing unit 16a has a called-side device for resetting a communication path when a called-side device that is determined to be not normal by the judging processing unit 16c occurs and the transmission port 14a is connected to the called-side device. Select a new device. For example, prior to the start of communication, the selection processing unit 16a selects any one of the arrival side devices R1 to Rn as a connection destination of the transmission port 14a. Then, if a failure occurs in the destination device after the communication is started, the selection processing unit 16a selects the destination device to be connected next in the order of the lowest number of the address (or a numerical value corresponding to the address). . When communication is resumed and a failure occurs next from that state, the selection processing unit 16a selects a destination device to be connected next in the order of the oldest number of the address (or a numerical value corresponding to the address). In this manner, the selection processing unit 16a alternately performs the address number order selection processing and the oldest number selection processing alternately.

  FIG. 5 is a schematic diagram showing the contents of the address list AL of FIG. In FIG. 5, for the sake of convenience, the addresses of the destination devices R1 to Rn are indicated by numerical values 1 to n. As shown in FIG. 5, the apparatus state is managed for each of the arrival side apparatuses R1 to Rn. The device status includes items such as normal (0), abnormal (1), blocked (2), other (3), and so on. The address list AL is a common database among the originating devices T1 to Tm in FIG.

  Next, operation in the above configuration will be described. First, at the start of communication, in each of the originating devices T1 to Tm, a destination device to be connected to is selected according to the address list AL, and then communication is started by the communication processing unit 16b. The determination processing unit 16c constantly monitors the communication state, and when a communication failure, a shortage of resources at the connection destination, or a busy message is received from the connection destination, the connection destination state is changed to an abnormal state, and this is indicated. It is described in the address list AL.

  Next, the communication processing unit 16b requests the selection processing unit 16a to select a destination device to be connected next. In response to this, the selection processing unit 16a selects the next connection destination. If this failure is the first failure that has occurred since the start of communication, the selection processing unit 16a obtains an address in the failure state from an unselected device among the called devices listed in the address list AL. Except for the above, candidate addresses are selected in ascending order. When the selection process is completed, the communication processing unit 16b reconnects the communication path to the selected destination device.

  When a failure is detected in any one of the destination devices R1 to Rn, the gateway device 1 periodically attempts to access the destination device in the failure state, and detects recovery from the failure. When the failure recovery is detected, the gateway device 1 returns the state of the corresponding device in the address list AL to normal and makes it the target for the next connection destination selection process.

  When the next failure occurs from this state, the selection processing unit 16a removes the address in the failure state from the unselected devices among the destination devices listed in the address list AL, and becomes a candidate address. Select in order of oldest. Thereby, a new reconnection destination is set.

  As described above, in the present embodiment, the calling-side devices T1 to Tm and the called-side devices R1 to Rn perform m-to-n communication, and the communication is always started from the calling-side devices T1 to Tm. When a failure occurs, a detour route is set by sequentially assigning the next connection destinations, for example, in ascending order of the address list AL. Next, when a failure occurs, a detour route is set by sequentially assigning the next connection destinations in the order of oldest addresses in the address list AL. The selection process based on the youngest number and the selection process based on the oldest number are alternately repeated every time a failure occurs.

By doing in this way, every time a failure occurs, the connection destinations of the calling side devices T1 to Tm are equally distributed to the normal destination side devices R1 to Rn. Therefore, it is possible to prevent the load from being concentrated on one destination device, and it is possible to prevent the entire system from going down due to the failure of one device. Furthermore, in this embodiment, a callee apparatus is autonomously determined by each caller apparatus T1 to Tm based on an address list AL stored in common for each callout apparatus T1 to Tm. As a result, for example, it is possible to obtain an effect that communication traffic of the communication network NET can be minimized.

  Therefore, when a failure occurs, it is possible to re-set a new communication path while distributing the load on the destination device, and it is possible to prevent the failure from being propagated in a chain due to the concentration of the load. It is possible to provide a communication system with improved performance.

[Second Embodiment]
In this embodiment, a description will be given of a technique capable of appropriately allocating connection destinations of a plurality of originating devices provided in the gateway device 1 not only between the gateway devices 1 but also within the gateway device 1.

  FIG. 6 is a conceptual diagram showing a communication system according to the second embodiment of the present invention. In FIG. 6, parts common to those in FIGS. 3 and 4 are given the same reference numerals, and only different parts will be described here. In FIG. 6, a plurality of gateway devices 1 and a plurality of FEPs 8 are connected to the communication network NET. The gateway device 1 includes a plurality of transmission ports 14a to 14p, and the FEP 8 includes a plurality of reception ports 20a to 20q. The transmission ports 14a to 14p correspond to respective boards when the gateway apparatus 1 includes a plurality of boards on which the function of the IP conversion unit 14 is mounted. In FIG. 6, it is preferable in terms of system design that the total number of reception ports 20a to 20q is larger than the total number of transmission ports 14a to 14p.

  In FIG. 6, the entities that perform m-to-n communication with each other are the transmission ports 14a to 14p and the reception ports 20a to 20q. That is, the transmission ports 14a to 14p correspond to the originating devices T1 to Tm in FIG. 3, respectively, and the receiving ports 20a to 20q correspond to the terminating devices R1 to Rn, respectively. Therefore, each of the reception ports 20a to 20q has a unique address.

  In FIG. 6, each gateway device 1 stores a management table MT in the storage unit M. The management table MT is a table in which the addresses of the reception ports 20a to 20q are associated with the number of transmission communication ports connected to the reception ports 20a to 20q in addition to the states of the reception ports 20a to 20q. It is a database.

FIG. 7 is a schematic diagram showing the contents of the management table MT of FIG. Management table MT is the address list AL in FIG. 5, a database with increased fields to describe the number of originating devices connected. In the example shown in FIG. 7, for example, five transmission ports are connected to the reception port having the address 1.

  In FIG. 6, the gateway device 1 includes a selection processing unit 16a, a communication processing unit 16b, and a determination processing unit 16c in the control unit 16 as in FIG. However, in the present embodiment, the selection processing unit 16a, the communication processing unit 16b, and the determination processing unit 16c have functions different from those in the first embodiment.

  That is, in the present embodiment, the selection processing unit 16a selects a reception port to be connected for each of the transmission ports 14a to 14p based on the contents of the management table MT. The communication processing unit 16b connects to the reception port selected by the selection processing unit 16a and starts communication with the connected reception port. The determination processing unit 16c monitors the state of communication started by the communication processing unit 16b, and determines the state of the reception port related to the communication.

  In particular, the selection processing unit 16a resets the communication path when a reception port determined to be not normal by the determination processing unit 16c occurs and any one of the transmission port 14a to the transmission port 14p is connected to the reception port. A new receiving port is selected. For example, prior to the start of communication, the selection processing unit 16a selects a connection destination for each of the transmission ports 14a to 14p from the reception ports 20a to 20q. When a failure occurs in the receiving port after connection is started, the selection processing unit 16a refers to the management table MT and selects the receiving port to be connected next in order to equalize the load on the receiving port on the destination side. To do.

  When communication is resumed and the next failure occurs from that state, the selection processing unit 16a refers to the management table MT again, and selects the reception port to be connected next in order to equalize the load on the reception port on the destination side. .

  Next, operation in the above configuration will be described. First, at the start of communication, each gateway device 1 selects a connection destination for each of the transmission ports 14a to 14p based on the addresses of the reception ports 20a to 20q described in the management table MT, and then communicates with the communication processing unit 16b. Is started. The determination processing unit 16c constantly monitors the communication state, and when a communication failure, a shortage of resources at the connection destination, or a busy message is received from the connection destination, the connection destination state is changed to an abnormal state, and this is indicated. It is described in the management table MT.

  Next, the communication processing unit 16b requests the selection processing unit 16a to select a reception port to be connected next by the transmission port connected to the reception port where the failure has occurred. In response to this, the selection processing unit 16a refers to the management table MT and preferentially selects a reception port with a small number of connections as a candidate. That is, the selection processing unit 16a selects the reception port to which the transmission port should be connected next in order to equalize the load of the reception ports 20a to 20q. When this selection process is completed, the communication processing unit 16b reconnects the communication path to the selected reception port.

  When a failure is detected in any of the reception ports 20a to 20q, the gateway device 1 periodically tries to access the reception port in the failure state, and detects recovery from the failure. When the failure recovery is detected, the gateway device 1 returns the state of the corresponding port in the management table MT to normal and makes it the target for the next connection destination selection process.

  When the next failure occurs from this state, the selection processing unit 16a removes the address in the failure state from the unselected ports among the reception ports described in the management table MT, and selects candidate addresses. select. Thereby, a new reconnection destination is set.

  As described above, in the present embodiment, the gateway apparatus 1 including the plurality of transmission ports 14a to 14p and the FEP including the plurality of reception ports 20a to 20q are provided, and the transmission ports 14a to 14p and the reception ports 20a to 20q are provided. In the communication system in which m-to-n communication is performed and communication is always started from the transmission ports 14a to 14p, a management table MT for managing the number of connections in each reception port 20a to 20q is stored in each gateway device 1. Then, based on the contents of the management table MT, the load applied to the reception ports 20a to 20q is made uniform by managing the connection destinations of the transmission ports 14a to 14p in an integrated manner.

  In other words, in the present embodiment, the management table MT is stored in the gateway device 1 so as to have a function capable of comprehensively managing connection destinations for the respective transmission ports 14a to 14p. Thereby, when setting a communication path in the communication network NET, each load of the receiving ports 20a to 20q can be equalized. Therefore, also in the present embodiment, it is possible to prevent a failure from being propagated in a chain due to load concentration, and to provide a communication system with improved reliability.

[Third Embodiment]
FIG. 8 is a system diagram according to the third embodiment of the present invention. In FIG. 8, parts common to FIG. In FIG. 8, a plurality of base stations CSA to CSC are accommodated in the gateway device 1. The gateway device 1 is connected to the IP network DN. The gateway device 1 may be connected to the circuit switching network XN. Communication from the gateway device 1 is connected to the Internet ITN via a plurality of routers 91 to 93 in the IP network DN.

  FIG. 9 is a functional block diagram of the gateway device 1 of FIG. 9 includes a subscriber line interface 11 connected to base stations CSA to CSC via a subscriber line 114, a subscriber line interface 12 accommodating the subscriber line 115, and a switching unit 100. Prepare. The switching unit 100 includes a circuit switching switch 13, a control unit 204, IP line control units 208 and 209, and a line concentrating unit 18.

  In FIG. 9, a subscriber line interface 11 accommodates subscriber terminals and wireless base stations via a subscriber line 114, and provides an ISDN (Integrated Service Digital Network) exchange side interface. The subscriber line interface 12 is connected to the exchange 3 of the circuit switching network XN via the subscriber line 115, and provides a terminal side interface of ISDN. That is, the subscriber line interface 12 connects the circuit switching switch 13 to the circuit switching network XN via the subscriber line 115. The communication capacity of the subscriber line 115 is designed in advance based on traffic demand prediction.

  The circuit switching switch 13 exchanges and connects a plurality of communication paths formed between the subscriber line interface 12, the IP network DN, and the subscriber network SN, and forms a communication link between terminal devices belonging to each network. That is, the circuit switching switch 13 performs circuit switching by exchanging time slots of time division multiplexed signal frames transmitted through the time division multiplexing bus 110. The control unit 204 executes various operation controls related to the circuit switching switch 13 and the gateway device 1.

The IP line control units 208 and 209 are provided between the circuit switching switch 13 and the IP network DN, and convert a protocol between the circuit switching switch 13 and the IP network DN. That is, the IP line control units 208 and 209 convert the time division multiplexed signal given from the circuit switching switch 13 via the time division multiplexing bus 110 into an IP packet. This IP packet is routed according to the destination IP address by a packet switch or the like and then sent to the IP network DN. The IP line control units 208 and 209 convert IP packets input from the IP network DN into time division multiplexed signals suitable for the interface with the circuit switching switch 13.
Particularly, the functions of the IP line control units 208 and 209 are mounted on a hardware board that is detachably provided in the gateway device 1 of FIG. The presence or absence of the board is detected by the control unit 204, and software related to the control of the IP line control units 208 and 209 is loaded in response to the detection of the board mounting.

  The concentrator 18 collects the internal bus 19 extended from the subscriber line interfaces 11 and 12, the circuit switching switch 13, and the IP circuit controllers 208 and 209, and between the control unit 204 of the circuit switching switch 13 and each unit. The exchange of various control signals (call control signals, etc.)

  In FIG. 9, 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.

  In FIG. 9, the gateway device 1 receives a call control signal at the internal control communication processing unit 207 in the control unit 204 via the line concentrator 18. Then, the circuit switching connection processing unit 205 determines whether this call control signal is a connection request to the IP network DN. If it is a connection request to the IP network DN, the connection destination determination processing unit 206 determines which IP line control unit (208, 209) is used and which router 91 to 93 is connected.

  When it is determined by the connection destination determination processing unit 206 which IP line control unit is to be used, the determined IP line control unit (in this case, the IP line control unit 208) is connected via the internal control communication processing unit 207. A connection request is given. In connection with this connection request, an identifier that can be recognized by the connection destination router is also given to the IP line control unit 208 as connection request information. Upon receiving the connection request, the IP line control unit 208 receives the connection request at the internal control processing unit 212 and detects a transmission packet by the packet detection unit 210. Communication with the router instructed in the connection request received by the internal control processing unit 212 is started by the IP network communication processing unit 211.

In the above configuration, both IP line control units 208 and 209 store the following table. The IP line control units 208 and 209 manage the number of used channels based on this table. In this table, the numbers in parentheses correspond to the reference numerals in FIG.

Further, each of the routers 91 to 93 stores the following table. The routers 91 to 93 manage the IP line control unit to be connected based on this table. In this table, the numbers in parentheses correspond to the reference numerals in FIG.

  FIG. 10 is a flowchart showing a processing procedure in the gateway device 1 of FIG. In FIG. 10, the gateway device 1 first selects an IP line control unit having the smallest number of used connection channels (step S1). Next, the gateway device 1 selects a router with the smallest number of connected IP line control units (step S2). Then, the gateway apparatus 1 determines a connection partner with the combination of the IP line control unit and the router selected in steps S1 and S2 (step S3), and starts communication via the IP network DN.

  FIG. 11 is a flowchart showing a processing procedure for determining a communication partner in an existing communication system for comparison. In FIG. 11, it is assumed that there are a plurality of channels capable of communication as in FIG. In FIG. 11, first, the youngest IP line control unit is selected in the order of numbers (step S11). For the selected IP line control unit, the presence / absence of a free channel is determined (step S12). If there is no free channel, the next IP line control unit is selected (step S13), and the IP line control unit having the free channel is selected. This process is repeated until is found.

When an IP line control unit with an empty channel is found (Yes in step S12), the youngest router is selected in order of number (step S14). Then, routers that can be used are searched in numerical order until a normal router is found (steps S15 and S16). When a combination of the IP line control unit and the router is found by such a series of processes, the connection partner is determined (step S17). However, because of such processing, the load is likely to be concentrated on one router, a bottleneck is generated, communication is likely to be delayed, and a network failure is caused.

  On the other hand, in this embodiment, the communication path is determined by combining the IP line control unit having the smallest number of used connection channels and the router having the smallest number of connected IP line control units. It is possible to prevent a failure from being propagated in a chain due to the concentration of the network, and to provide a communication system with improved reliability.

  In addition, this invention is not limited to the said embodiment as it is. For example, in the first embodiment, the connection destinations are assigned in the order of younger or older addresses. As a similar method, a numerical value indicating an address may be divided by the number of the originating devices T1 to Tm, and a connection destination may be allocated based on the remainder (modulo: mod). Also, the result of adding the number of occurrences of the failure to the remaining numerical value can be used for connection destination allocation.

  Furthermore, the present invention can be embodied by modifying the components 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 constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined, and the methods described in the respective embodiments may be combined.

1 is a system diagram showing an embodiment of a communication system according to the present invention. The system diagram which shows the existing audio | voice communication system. 1 is a conceptual diagram showing a communication system according to a first embodiment of the present invention. The functional block diagram which shows the principal part structure of the originating side apparatuses T1-Tm in FIG. FIG. 5 is a schematic diagram showing the contents of an address list AL in FIG. 4. The conceptual diagram which shows the communication system concerning the 2nd Embodiment of this invention. FIG. 7 is a schematic diagram showing the contents of the management table MT of FIG. 6. The system figure concerning 3rd Embodiment of this invention. The functional block diagram of the gateway apparatus 1 of FIG. The flowchart which shows the process sequence in the gateway apparatus 1 of FIG. The flowchart which shows the process sequence at the time of determining a communicating party other party in the existing communication system.

Explanation of symbols

  AL ... address list, SN ... subscriber network, DN ... IP network, XN ... circuit switching network, IN ... Internet, ME ... network management device, NET ... communication network, T1-Tm ... calling side device, R1-Rn ... arrival Side device, M ... storage unit, MT ... management table, 1 ... gateway device, CS1 ... base station, PS1 ... wireless terminal, 3 ... exchange, 5-7 ... subscriber terminal, 8 ... FEP server, 9 ... router, 11 , 12 ... subscriber line interface, 13 ... circuit switching switch, 14 ... IP conversion unit, 14a to 14p ... transmission port, 15 ... packet switch, 16 ... control unit, 16a ... selection processing unit, 16b ... communication processing unit, 16c Reference processing unit, 18 ... Concentration unit, 19 ... Internal bus, 20a to 20q ... Reception port, 100 ... Switching unit, 110 ... Time division multiplexed bus, 114 ... Subscriber line, 115 ... Subscription Line, CSA to CSC ... Base station, 91 to 93 ... Router, 204 ... Control unit, 205 ... Line switching connection processing unit, 206 ... Destination determination processing unit, 207 ... Internal control communication processing unit, 208,209 ... IP line Control unit 210 ... Packet detection unit 211 ... IP network communication processing unit 212 ... Internal control communication processing unit

Claims (5)

A communication network and a plurality of communication devices that perform many-to-many communication via the communication network, the plurality of communication devices each having a plurality of address information uniquely defined by distinguishable numerical values In a communication system that is positioned as one of a plurality of calling-side devices and a plurality of calling-side devices that connect to one called-side device and actively start communication based on the address information,
Each of the plurality of communication devices that are the originating device is:
An address list in which each address information of the plurality of destination devices is tabulated in association with the status of the destination device;
Selection means for selecting a destination device to be connected based on the contents of the address list;
Communication means for connecting to the destination apparatus selected by the selection means and starting the communication;
Determination means for determining the state of the called-side apparatus related to the communication from the communication state started by the communication means;
The selection means selects the destination device to be connected in order of the numerical value corresponding to the address information, and selects the destination device to be connected in the numerical order of the numerical value corresponding to the address information. The communication system is characterized in that the processing is alternately performed every time a called-side device determined to be not normal by the determination means is generated. 2. The communication system according to claim 1, wherein the selection unit performs the process of selecting the destination side device to be connected each time a destination side device determined to be not normal by the determination unit occurs. . The communication system according to claim 1, wherein the number of the destination devices is larger than the number of the originating devices. A communication network and a plurality of communication devices that perform many-to-many communication via the communication network, the plurality of communication devices each having a plurality of address information uniquely defined by distinguishable numerical values In a communication system that is positioned as one of a plurality of calling-side devices and a plurality of calling-side devices that connect to one called-side device and actively start communication based on the address information,
Each of the plurality of communication devices that are the originating device is:
An address list in which each address information of the plurality of destination devices is tabulated in association with the status of the destination device;
Multiple communication ports,
Selection means for selecting a destination device to be connected to the plurality of communication ports based on the contents of the address list;
Communication means for connecting the plurality of communication ports to the destination device selected by the selection means and starting the communication;
Determination means for determining the state of the called-side apparatus related to the communication from the communication state started by the communication means;
The selection means selects a destination device to be connected to each of the plurality of communication ports in order of numerical values corresponding to the address information, and a destination device to be connected to each of the plurality of communication ports. The communication system is characterized in that the process of selecting the chronological order of the numerical values corresponding to the address information is alternately performed each time a called-side device determined to be not normal by the determination means is generated. The communication system according to claim 4, wherein the number of the destination devices is larger than the number of the plurality of communication ports.

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