JP2008199394A - Communication system and gateway device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system and a gateway device that can accommodate an IP network without causing trouble of address depletion. <P>SOLUTION: I' interfaces of a base station and a network side are IP-configured and a TDM signal from the base station is IP-packetized. The gateway device 10 also IP-packetizes line-switched PCM data by an optical accommodation unit 13. Consequently, a subscriber network 300 is available as an IP network and the transmission band can be expanded as compared with an existent time-division interface. Further, the gateway device 10 is provided with an address converting unit 67 (or 93), and mutual conversion between a global address of the IP network 200 and a private address of a subscriber network 300 is performed to effectively use resources of global addresses. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  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.

  Gateway devices are used to interconnect different communication networks such as PSTN and 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. These all play a role as a network interface for the IP network.

Some gateway devices of this type accommodate base stations such as PHS (Personal Handy-phone System) and so-called mobile phone systems. Considering the recent trend of communication total IP networking, it is considered to convert this accommodated line to IP. However, the problem of IP address depletion is well known, and this type of device is no exception. Patent Document 1 discloses a technique for solving such a problem, but in this document, communication between the mobile terminal and the PSTN is not assumed, and common sense such as conversion between a global address and a private address is disclosed. New technology is disclosed.
Japanese Patent Laid-Open No. 10-303981

As described above, in the gateway device that interconnects the circuit switching network and the IP network, it is necessary to solve the problem of address depletion when the circuit accommodating the base station of the mobile communication system is converted to IP.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a communication system and a gateway device that can accommodate an IP network without causing the problem of address exhaustion.

In order to achieve the above object, according to an aspect of the present invention, in a communication system comprising a subscriber network, a synchronous communication network, and an IP network using a global address, the subscriber network, the synchronous communication network, A gateway device that mutually converts a communication protocol with the IP network and interconnects the networks, and an IP conversion unit that converts the interface between the subscriber network and the gateway device into an IP using a private address The gateway device terminates the synchronous communication network and generates an in-device signal; and a packet network terminator that terminates the IP network and generates the in-device signal; A subscriber network termination unit that terminates the subscriber network via an IP interface and generates the in-device signal; the synchronous network termination unit; and the packet network termination unit. And a time division switch for exchanging in-device signals respectively generated at the subscriber network termination unit, and an address conversion processing unit for converting addresses between the subscriber network and the IP network. A communication system is provided.
By taking such means, it becomes possible to use a private address instead of a global address in an IP subscriber network. Accordingly, the resources of the global address can be effectively used, and the problem of address exhaustion can be solved.

  According to the present invention, it is possible to provide a communication system and a gateway device that can accommodate an IP network without causing a problem of address exhaustion.

  FIG. 1 is a system diagram showing an embodiment of a communication system according to the present invention. The system shown in FIG. 1 includes a circuit switching network 100 as a synchronous communication network, an IP network 200 as a packet communication network, and a subscriber network 300. These networks are connected to the gateway device 10. The circuit switching network 100 is accommodated in the gateway device 10 via, for example, the I ′ interface, and the IP network 200 is accommodated via the IP.

The gateway device 10 mutually converts communication protocols among the subscriber network 300, the circuit switching network 100, and the IP network 200, and interconnects these networks. In the gateway device 10, data of each network is exchanged by a synchronous exchange connection using a time division switch.
Here, the IP network uses a global address for transmission of IP packets, that is, the Internet.

  The subscriber network 300 includes a plurality of base stations 21 to 2n. Each of the base stations 21 to 2n accommodates a mobile communication terminal PS such as PHS via a wireless line. Among these, the base station 21 has a line directly connected to the gateway apparatus 10 via the I ′ interface and a line connected to the gateway apparatus 10 via the adapter 30. The base station 22 is also accommodated in the gateway device 10 via the adapter 30. The base station 2n includes a built-in adapter 50, and is accommodated in the gateway device 10 from the built-in adapter 50 via an IP interface.

  The space between the adapter 30 and the gateway device 10 and the space between the base station 2n and the gateway device 10 are accommodated in the gateway device 10 via the existing dark fiber network 400. The optical fibers F drawn from the base stations 21 to 2n are concentrated at the concentration unit 500 and connected to the gateway device 10.

  The dark fiber network 400 is an IP network using, for example, PON (Passive Optical Network) technology. The network / node interface in which the base stations 21 to 2n are accommodated in the dark fiber network 400 is IP-configured by the function of the base station itself or the adapter 30. On the other hand, some base stations 21 with two output interfaces are accommodated in the gateway apparatus 10 with the I ′ interface intact.

  The gateway device 10 includes a public network interface 11 that accommodates the circuit switching network 100 and an IP interface 12 that accommodates the IP network 200. The public network interface 11 terminates the circuit switching network 100 and generates time-division PCM (Pulse Code Modulation) data. The IP interface 12 terminates the IP network 200 and generates PCM data.

  Further, the gateway device 10 includes a light accommodation unit 13, a packet conversion unit 14, and a main control unit 15. The light accommodation unit 13 accommodates the base stations 21 to 2n via the optical fibers F concentrated in the concentration unit 500. That is, the light accommodating unit 13 performs optical / electrical conversion on an optical signal coming from the dark fiber network 400 and terminates the IP packet to generate PCM data.

The main control unit 15 includes a function for comprehensively controlling the gateway device 10 and a time switch 15a. The time switch 15a switches and connects the circuit switching network 100, the IP network 200, and the subscriber network 300 by switching PCM data. At this time, the signal for the IP network 200 is converted into an IP packet by the packet conversion unit 14, and the data for the dark fiber network 400 is converted into an IP packet by the light accommodating unit 13.
Inside the gateway device 10, time-division PCM data is transmitted via a PCM highway (PCM-HWY). The IP packet is transmitted via a control LAN (Local Area Network) or a data LAN.

  The optical accommodation unit 13 includes an optical switch 13a, an optical interface (I / F) 13b, a signal processing unit 13c, and a packet conversion unit 13d. The optical switch 13 a switches the path of the optical fiber F accommodated from the dark fiber network 400. As a result, the base stations 21 to 2n can be switched and operated, and improvement of fault tolerance performance can be promoted.

  An optical signal introduced into the apparatus via the optical switch 13a is converted into an electric signal by an optical / electrical conversion element (not shown) provided in the optical interface 13b, and an IP packet is reproduced. The IP packet is routed by the data layer 2 switch (L2SW) of the signal processor 13c and sent to the IP interface 12 or the packet converter 13d. The packet conversion unit 13d mutually converts a packet flowing through the control LAN and the data LAN and time division data flowing through the PCM-HWY.

FIG. 2 is a diagram showing details of the light accommodating portion 13 and a data flow. FIG. 2 shows a data flow when the in-device LAN from the signal processing unit 13c to the IP interface 12 is dedicated.
In FIG. 2, the light accommodating unit 13 includes a clock processing unit 20. The clock processing unit 20 adds timing information when packetizing the PCM data. As a result, the PCM data and the synchronization timing can be transmitted on the same line, and a base station having only an ISDN interface can be dealt with.

  In the optical accommodation unit 13 in FIG. 2, transmission data including voice or binary code is transmitted through a path from the optical interface 13 b to the data L2SW 13 c to the packet conversion unit 14 to the main control unit 15. The transmission data is exchanged by the time switch 15 a of the main control unit 15, packetized again by the packet conversion unit 14, and then connected to the IP network via the IP interface 12.

  If the base station (base station 21) has both the IP interface and the ISDN interface, the synchronization information can be transmitted by ISDN. Transmission data can be connected to the IP network via the IP interface 12 from the IP interface of the base station through the optical interface 13b to the data L2SW 13c as a packet.

In the above configuration, the I ′ interface between the base station and the network side is all IP. That is, the TDM signal from the base station is converted into an IP packet. Also in the gateway device 10, circuit-switched PCM data is converted into IP packets in the light accommodating unit 13. As a result, the subscriber network 300 becomes an IP network, and the transmission band can be expanded as compared with the existing time division interface.
Here, in the present embodiment, a private address effective in the subscriber network 300 is used for transmission of the IP packet in the subscriber network 300.

  FIG. 3 is a functional block diagram showing an embodiment of the signal processing unit 13c of FIG. The signal processing unit 13c is roughly divided into a block including a data layer 2 switch and a block including an optical control unit. The data layer 2 switch exchanges packets between the optical interface 13b, the packet converter 13d, and the IP interface 12. Control related to these processes and switching control of the optical switch unit 13a are performed by the light control block.

  That is, the signal processing unit 13c includes redundant data layer 2 switches (L2SW) 61 and 62, an optical control unit 63, a layer 2 switch 64, a physical layer processing unit 65, a relay 66, an address conversion unit 67, and a ROM 68. A RAM 69 is provided. An IP packet sent from the subscriber network 300 via the active L2SW is sent to the address translation unit 67, and an address translation process is performed. That is, the private address used in the subscriber network 300 is converted into a global address of the IP network 200 by the address conversion unit 67. The global address of the IP packet addressed from the IP network 200 to the subscriber network is converted into a private address of the subscriber network 300 by the address conversion unit 67.

  An IP packet to the IP network 200 is routed from the active L2SW by the optical control unit 63 and the data LAN layer 2 switch 64, passes through the data LAN in the apparatus, and passes through the IP interface 12 to the IP network 200. Sent out. An IP packet addressed to the circuit switched network 100 is sent from the optical control unit 63 to the packet conversion unit 14 and the main control unit 15 in FIG. 1 via the physical layer processing unit 65 and the relay 66. In addition, the light control unit 63 also generates an optical switch switching signal for switching the optical switch 13a of FIG.

  FIG. 4 is a functional block diagram showing details of the embodiment of the address conversion unit 67. Private addresses are registered in the private address register 71 and global addresses are registered in the global address register 72 in advance. The contents are stored in the private address table 73 and the global address table 74.

  Communication from the subscriber network 300 to the IP network 200, that is, communication from the private side to the global side is performed by the following procedure. First, when an IP packet from a base station on the private side is received by the reception buffer 75, a port number of a TCP (Transmission Control Protocol) layer is written in the port number register 81. Next, the private address of the IP layer transmission source is written in the private address register 71. This is compared with the contents of the private address table 73 by the comparison unit 76, and if they match, the packet transmission buffer 77 writes the global address in the private address area (IP packet prescribed field). Thereafter, packet transmission after this writing is permitted, and this IP packet is transmitted to the global side (IP network 200).

  Communication from the IP network 200 to the subscriber network 300, that is, communication from the global side to the private side is performed in the following procedure. First, when an IP packet from the global-side IP interface 12 is received by the reception buffer 78, the global address of the IP layer transmission source is written in the global address register 72. This is compared with the contents of the global address table 74 by the comparison unit 79. If they match, the port number of the TCP layer is written into the port number register 80, and this is compared with the port number register 81 by the comparison unit 82. The If they match, the packet transmission buffer 83 writes the private address in the global address area, and permits transmission of the IP packet after this writing. In this way, the IP packet is transmitted to the private side (subscriber network 300).

FIG. 5 is a functional block diagram showing an embodiment of the packet conversion unit 14 of FIG. The packet conversion unit 14 acquires PCM data flowing through the PDM-HW via a PCM highway interface (PDM HW I / F) 91 and sends the acquired data to a DSP (Digital Signal Processor) 92. The DSP 92 converts the PCM data into IP packets using VoIP (Voice over IP) technology. At that time, address conversion between the private address and the global address is performed by the address conversion unit 93. The configuration and operation of the address conversion unit 93 are the same as those in FIG.
In addition, the packet conversion unit 14 is connected to the control LAN in order to monitor and control the packet conversion unit 14 from the main control unit 15 (FIG. 1), and to control these locally. The control unit 95 is provided.

  By providing the address conversion unit 93 in the packet conversion unit 14 as shown in FIG. 5, an internal control LAN from the signal processing unit 13c can be provided without dedicated data LAN from the signal processing unit 13c to the IP interface 12. It is possible to exchange IP packets via the network, and it is possible to facilitate simplification of the device configuration.

  As described above, in this embodiment, the I ′ interface between the base station and the network side is all IP, and the TDM signal from the base station is IP packetized. Also in the gateway device 10, circuit-switched PCM data is converted into IP packets in the light accommodating unit 13. As a result, the subscriber network 300 becomes an IP network, and the transmission band can be expanded as compared with the existing time division interface. In addition, the address conversion unit 67 (or 93) is provided in the gateway device 10 to convert the global address of the IP network 200 and the private address of the subscriber network 300 to each other, thereby effectively using resources of the global address. Is possible.

  Since a normal system includes hundreds of thousands of base stations, it is not a good idea to assign a global address to each base station in terms of IP address resources. Therefore, by assigning a private address to the IP address of the base station and assigning a global address to the connection interface with the IP network 200, the IP address can be used effectively. Furthermore, the configuration of FIG. 4 can be easily realized by hardware logic. As a result, the processing can be speeded up and the delay time can be shortened compared to the address conversion processing by software.

  For these reasons, it is possible to provide a communication system and a gateway device that can accommodate an IP network without the problem of address exhaustion.

  In addition, this invention is not limited to the said embodiment as it is. For example, in the above description, the subscriber network 300 is opticalized using the optical fiber F. However, the same implementation can be performed in a communication network with a metallic cable. In this case, the dark fiber network 400 can be replaced with a dry copper network.

  Furthermore, the present invention can be embodied by modifying the constituent elements without departing from the gist of the embodiment 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.

1 is a system diagram showing an embodiment of a communication system according to the present invention. The figure which shows the detail of the light accommodating part 13 of FIG. 1, and the flow of data. The functional block diagram which shows embodiment of the signal processing part 13c of FIG. The functional block diagram which shows the detail of embodiment of the address conversion part 67. FIG. The functional block diagram which shows embodiment of the packet conversion part 14 of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Circuit switched network, 200 ... IP network, 300 ... Subscriber network, 400 ... Dark fiber network, 500 ... Concentrator, 10 ... Gateway apparatus, 21-2n ... Base station, PS ... Mobile communication terminal, 30 ... Adapter, DESCRIPTION OF SYMBOLS 11 ... Public network interface, 12 ... IP interface, 13 ... Optical accommodation part, 14 ... Packet conversion part, 15 ... Main control part, 13a ... Optical switch, 13b ... Optical interface, 13c ... Signal processing part, 13d ... Packet conversion part , 20 ... Clock processing unit, 31 ... CPU, 32 ... LAN interface, 33 ... TDM interface, 34 ... Clock processing unit, 35 ... Electrical / optical conversion unit, 36 ... Electrical / optical conversion unit, 51 ... CPU, 52 ... LAN Switch 53... Clock processor 54. Signal processor 55 55 Electric / optical converter 61 and 62 Layer 2 switch for data L2SW), 63 ... light control unit, 64 ... layer 2 switch, 65 ... physical layer processing unit, 66 ... relay, 67 ... address conversion unit, 68 ... ROM, 69 ... RAM, 71 ... private address register, 72 ... global address Register, 73 ... Private address table, 74 ... Global address table, 75 ... Reception buffer, 76 ... Comparison unit, 77 ... Packet transmission buffer, 78 ... Reception buffer, 79 ... Comparison unit, 80 ... Port number register, 81 ... Port number Register, 82 ... Comparison unit, 83 ... Packet transmission buffer, 91 ... PCM highway interface (PDM HW I / F), 92 ... DSP, 93 ... Address conversion unit, 94 ... Physical layer processing unit, 95 ... Control unit, F ... Optical fiber

Claims (9)

In a communication system comprising a subscriber network, a synchronous communication network, and an IP (Internet Protocol) network using a global address,
A gateway device that mutually converts a communication protocol between the subscriber network, the synchronous communication network, and the IP network and interconnects these networks;
IP conversion means for converting the interface between the subscriber network and the gateway device into IP using a private address,
The gateway device is
A synchronous network terminating unit that terminates the synchronous communication network and generates an in-device signal;
A packet network termination unit that terminates the IP network and generates the in-device signal;
A subscriber network termination unit for terminating the subscriber network via the IP interface and generating the in-device signal;
A time division switch for exchanging in-device signals respectively generated at the synchronous network termination unit, the packet network termination unit, and the subscriber network termination unit;
A communication system comprising an address translation processing unit for translating addresses between the subscriber network and the IP network. When the subscriber network includes a base station that wirelessly accommodates mobile communication terminals,
The communication system according to claim 1, further comprising: an opticalization unit configured to connect the base station and the gateway device via an optical fiber to opticalize the interface. The photonization means includes:
An electrical / optical converter that is provided in the subscriber network and that electrically / optically converts a signal from the mobile communication terminal received at the base station and sends the signal to the optical fiber;
The communication system according to claim 2, further comprising: an optical / electrical conversion unit that is provided in the gateway device and performs optical / electrical conversion on an optical signal that arrives via the optical fiber. The communication system according to claim 2, wherein the opticalizing unit is provided in the base station. The subscriber network comprises a plurality of the base stations,
The communication system according to claim 2, further comprising an optical concentrator that collects optical fibers that are respectively extended from the plurality of base stations and connects the optical fibers to the gateway device. The communication system according to claim 5, wherein the gateway device includes an optical switching unit for switching and operating the plurality of base stations. A gateway device that mutually converts a communication protocol between an IP (Internet Protocol) network using a global address, a subscriber network using a private address, and a synchronous communication network, and interconnects these networks,
A synchronous network terminating unit that terminates the synchronous communication network and generates an in-device signal;
A packet network termination unit that terminates the IP network and generates the in-device signal;
A subscriber network termination unit for terminating the subscriber network via the IP interface and generating the in-device signal;
A time division switch for exchanging in-device signals respectively generated at the synchronous network termination unit, the packet network termination unit, and the subscriber network termination unit;
A gateway apparatus comprising an address conversion processing unit for converting addresses between the subscriber network and the IP network. The subscriber network includes a base station that wirelessly accommodates the mobile communication terminal, and the base station performs electrical / optical conversion of a signal from the mobile communication terminal received by the base station and is connected to the gateway device. When equipped with an electrical / optical converter that sends out to the fiber,
The gateway apparatus according to claim 7, further comprising an optical / electrical conversion unit configured to optically / electrically convert an optical signal arriving via the optical fiber. When the subscriber network comprises a plurality of base stations,
9. The gateway device according to claim 8, further comprising an optical switching unit for switching and operating the plurality of base stations.

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