JP7469908B2 - Line connection control system and line connection control method - Google Patents

Description

The present invention relates to a line connection control system and a line connection control method.

Conventionally, in IP connections between multiple bases via exchanges, IP packets are received and voice data is taken into the exchange, which then performs processing such as IP packet conversion and then forwards the data to the exchange at the next base. For example, in Patent Document 1, when terminals are interconnected, the voice compression method and transmission period to be set at the calling terminal and called terminal are determined as voice communication control information according to predetermined voice quality adjustment rules based on the voice communication management information of the calling terminal base and the voice communication management information of the called terminal base, and the determined voice communication control information is transmitted to the calling terminal and called terminal.

JP 2006-157661 A

As in the past, when IP packets are forwarded, if a switch takes in voice data and performs processing such as IP packet conversion, voice delays occur. Voice delays become more pronounced the more switches and relay stations are involved in the communication between bases. One communication method that prevents voice delays is peer-to-peer connection, but this method does not retain route information in the switches and relay stations on the communication path, making it impossible to know the route between the call origin and destination.

One aspect of the present invention aims to provide a technology that can avoid audio delays while retaining route information.

The line control system according to one aspect of the present invention is a line connection control system that controls the connection of a call line between terminals via at least one or more exchanges or relay stations, and the exchange or relay station is configured as a line connection control system characterized in that it has a first communication unit that receives a voice signal from a terminal connected to the exchange or relay station, a second communication unit that transfers the voice signal to another exchange or relay station different from the exchange or relay station, and a call control unit that determines whether to transfer the voice signal to the other relay station or exchange based on a setting table that defines whether to IP forward the voice signal received by the first communication unit, and when it is determined that the voice signal is to be transferred to the other relay station or exchange, does not perform a predetermined process on the voice signal by the signal processing unit, and causes the second communication unit to transfer the voice signal to the other relay station or exchange together with the address of the own device.

According to one aspect of the present invention, it is possible to avoid audio delays while retaining route information.

FIG. 2 is a diagram illustrating an example of the configuration of a line network in the present embodiment. 1 is a diagram showing the functional configuration of an exchange and a relay station, and the concept of a line connection control method via these devices. FIG. 13 is a diagram illustrating an example of the configuration of a setting table. FIG. 11 is a diagram showing an example of a connection sequence performed in the present system. 5 is a flowchart showing a processing procedure of the IP forwarding setting process shown in FIG. 4; 1 is a diagram showing the functional configuration of an exchange and a relay station, and the concept of a line connection control method via these devices (peer-to-peer connection). 1 is a diagram showing the functional configuration of an exchange and a relay station, and the concept of a line connection control method via these devices (VoIP connection).

The following describes in detail an embodiment of the line connection control system and line connection control method according to the present invention with reference to the attached drawings.

Figure 1 is a diagram showing an example of the configuration of a line connection control system 1000 in this embodiment. The line connection control system 1000 has a relay station 100 that constitutes a multi-layered line network (three layers in Figure 1), and an exchange 200 that constitutes a terminal station. The relay station 100 in the top layer (first layer) is connected to the relay station 100 in the next lower intermediate layer (second layer) via a network N12. Similarly, the relay station 100 in the second layer is connected to the relay station 100 in the next lower third layer via a network N23, and the relay station 100 in the third layer is connected to the lower terminal layer via a network N34. As shown in Figure 2, in reality, a terminal such as a telephone installed at a base is connected to the end of each terminal layer.

Figure 2 shows the functional configuration of an exchange and a relay station, and the concept of a line connection control method via these devices. As an example, Figure 2 shows a case where a line between terminal T1 at one location and terminal T2 at another location is controlled via exchange 200J, relay station 100D, and exchange 200K, but the same can be considered for the other exchanges and relays shown in Figure 1. Although not specifically shown below, terminals T1 and T2 are configured from general terminals capable of IP communication, and the number of terminals connected to the exchange is not limited to the terminals shown in Figure 2, and multiple terminals may be connected.

The exchange 200 is a general computer having a CPU (Central Processing Unit) and memory as hardware, and is a device that receives calls from the terminal T1 and performs processes such as protocol conversion between the IP network and the trunk line, which is a public network, and control of incoming and outgoing calls. In the following, the exchange 200J will be described as a representative, but the same applies to the exchange 200K.

As shown in FIG. 2, the switch 200J is configured to include a call control unit 201 and a multiplexing processing unit 202. The call control unit 201 further includes an IP call communication unit 2011 and a trunk line call communication unit 2012.

The call control unit 201 is a processing unit that controls calls with other devices (e.g., terminal T1) and calls with the relay station 100. As will be described later in detail, when the call control unit 201 receives a voice signal, if the received voice signal is set to be IP forwarded, the call control unit 201 rewrites the destination recorded in the header of the voice signal from the address of the device itself to the address of the forwarding destination (e.g., the IP address of the relay station 100D), and then forwards the voice signal together with the address of the device itself to the rewritten destination without handing it over to the multiplexing processing unit 202. The call control unit 201 stores and holds route information that associates the voice signal with the IP address or MAC address of the device itself in a storage medium such as the memory of the device itself, along with forwarding the rewritten voice signal. The following explanation is based on the assumption that an IP call is being made between terminals T1 and T2, but the exchange or relay station under which each terminal is managed (for example, the correspondence between the telephone number, IP address, and MAC address of each terminal and the IP address and MAC address of the exchange or relay station that manages each terminal, and the layout relationship of the terminals, exchanges, and relay stations as shown in Figure 1) is assumed to be predetermined, for example, by a table (correspondence table) in each exchange or relay station.

The IP call communication unit 2011 is a processing unit that transmits and receives call control signals C1 and voice signals R1 (call control signals C4 and voice signals R5 in the case of the exchange 200K) with the terminal T1, and transmits voice signals R2 (voice signals R6 in the case of the exchange 200K) to the relay station 100D. The trunk line call communication unit 2012 is a processing unit that transmits and receives call control signals C2 and voice signals R7 (call control signals C3 and voice signals R3 in the case of the exchange 200K) with the relay station 100D, and transmits voice signals R8 (voice signals R4 in the case of the exchange 200K) to the terminal T1.

Furthermore, the call control unit 201 stores in a storage medium such as an internal memory a setting table 211 that determines whether or not to perform IP forwarding when controlling calls from other devices, such as calls from terminal T1 or calls from relay station 100D. This table will be described later with reference to FIG. 3. This table is stored in each of the exchanges 200 and relay stations 100 shown in FIG. 1.

The multiplexing processing unit 202 is a processing unit that performs time division multiplexing (TDM: Time Division Multiplex) of the voice signal (RTP: Real-time Transport Protocol) between the terminal T1 and the relay station 100 and codec processing of the voice signal. The processing of each unit of the exchange 200 will be described later.

The relay station 100 is a general computer having a CPU, memory, etc. as hardware, and is a device that performs processing to transfer call control signals and voice signals received from other devices such as the exchange 200 to other devices such as other exchanges 200. Below, relay station 100D will be described as a representative example, but the same applies to the other relay stations 100.

As shown in FIG. 2, relay station 100D is configured to have call control unit 101 and multiplexing processing unit 102. Call control unit 101 further has first trunk line call communication unit 1011 and second trunk line call communication unit 1012. First trunk line call communication unit 1011 and second trunk line call communication unit 1012 differ from exchange 200 in that they transmit and receive call control signals and voice signals with other relay stations 100, but since they basically have the same functions as exchange 200, their description will be omitted here.

Figure 3 is a diagram showing an example of the configuration of the setting table 211. The following describes the setting table 211, but the same applies to the setting table 111. As shown in Figure 3, the setting table 211 stores a route ID for identifying a relay station on a communication path, an address of a relay station connected to the communication path identified by the route ID, and a setting flag indicating whether or not IP forwarding is performed at the relay station of the address, in association with each other. Figure 3 shows, for example, that IP forwarding is set at the relay stations indicated by stations A, B, C, D, and G, while IP forwarding is not set at the relay stations indicated by stations E and F.

Figure 4 is a diagram showing an example of a connection sequence performed in this system. As shown in Figure 4, first, terminal T1 accepts a call operation to terminal T2 from an operator (S401). When terminal T1 accepts the call operation, it generates connection information including, for example, the telephone number of terminal T2, which is the connection destination, and connection source information such as the telephone number, IP address, and MAC address of terminal T1, which is the connection source.

Terminal T1 outputs the connection information it has generated, starts a session with terminal T2 via exchange 200J, relay station 100D, and exchange 200K, and makes a call (S402-S405). After that, exchange 200J, relay station 100D, exchange 200K, and terminal T2 each respond to the effect that they are forwarding the request (S406-S409).

Terminal T2 outputs a ringing tone (S410) and transmits a response (Ringing) to terminal T1 via exchange 200J, relay station 100D, and exchange 200K (S411-S414). Terminal T1 starts outputting the ringing tone to the operator (S415).

After that, when terminal T2 receives a response operation from the operator to answer the call (S416), it stops outputting the ringtone (S4161) and transmits a response (OK) to terminal T1 via exchange 200J, relay station 100D, and exchange 200K (S417 to S420).

As confirmation, terminal T1 transmits a request (ACK) to terminal T2 via exchange 200J, relay station 100D, and exchange 200K (S422 to S425).

When each of the exchange 200J, relay station 100D, and exchange 200K confirms that it has received the request (ACK) from the respective senders, it refers to the connection destination information output and received from terminal T1 and performs IP forwarding setting processing (S426, S427, S428). The IP forwarding setting processing will be described later with reference to FIG. 5.

When the IP forwarding setting process is completed, a call is started between the operator of terminal T1 and the operator of terminal T2, and voice signals are transmitted and received between terminal T1 and terminal T2 via exchange 200J, relay station 100D, and exchange 200K (S429). As described below, in the call at this step, voice signals are forwarded without internal processing being performed in the exchange or relay station.

When terminal T1 receives a disconnect operation from the operator to end the call (S430), it transmits a request (BYE) to terminal T2 via exchange 200J, relay station 100D, and exchange 200K (S431-S434). When terminal T2 outputs a BT (Busy Tone) (S435), it transmits a response (OK) to terminal T1 via exchange 200J, relay station 100D, and exchange 200K (S436-S439).

When each of the exchange 200J, relay station 100D, and exchange 200K confirms in steps S436 to S439 that it has received the above-mentioned response (OK) from the respective senders, it cancels the IP forwarding settings made in steps S426, S427, and S428, and the call ends (S440, S441, S442). When these processes are completed, the connection sequence shown in FIG. 4 ends.

Figure 5 is a flowchart showing the procedure for the IP forwarding setting process shown in Figure 4. Below, we explain the case where the IP forwarding setting process is performed by the exchange 200J, but the same can be considered for the relay station 100D and the exchange 200K.

The call control unit 201 of the exchange 200J determines whether the IP call communication unit 2011 has received a request (ACK) from terminal T1 (S501).

When the IP call communication unit 2011 determines that it has received a request (ACK) from terminal T1 (S501; Yes), the IP call communication unit 2011 performs connection processing to transmit a voice signal to terminal T1 in order to start a call, and the trunk line call communication unit 2012 performs connection processing to transmit a voice signal to relay station 100D. On the other hand, when the IP call communication unit 2011 determines that it has not received a request (ACK) from terminal T1 (S501; No), it remains in standby.

When the call control unit 201 performs the above connection process, it reads the setting table 211 stored in a storage medium such as a memory, and determines whether the IP forwarding setting of the relay station 100D (e.g., station D) on the communication path is ON (S503). If the call control unit 201 determines that the IP forwarding setting of the relay station 100D on the communication path is ON (S503; Yes), it further determines whether the MAC address of the destination relay station 100D has been acquired (S504). If the call control unit 201 determines that the MAC address of the relay station 100D has not been acquired (S504; No), it performs ARP (Address Resolution Protocol) processing to acquire the MAC address of the destination relay station from the relay station 100D connected by the above connection process (S506).

If the call control unit 201 determines in S504 that it has acquired the MAC address of the destination relay station 100D (S504; Yes), it turns on the IP forwarding setting according to the setting determined in S503, rewrites the destination recorded in the header of the voice signal received from terminal T1 from its own device address to the address of the forwarding destination, and then forwards the voice signal together with its own device address from the trunk line call communication unit 2012 to the relay station 100D without importing it into the multiplexing processing unit 202, and stores and retains route information that associates the voice signal with the IP address or MAC address of its own device in a storage medium such as a memory of its own device (S505).

If the call control unit 201 determines in S503 that the IP forwarding setting of the relay station 100D on the communication path is not ON (S503; No), it does nothing and ends the IP forwarding setting process shown in FIG. 5. In this case, the destination recorded in the header of the voice signal received from terminal T1 remains the same as the local device, so the voice signal received from terminal T1 is not IP forwarded. Therefore, as in the conventional case, the call control unit 201 takes the voice signal received from terminal T1 into the multiplexing processing unit 202, performs time division multiplexing and codec processing on the voice signal, and then transfers the voice signal to the relay station 100D.

Thus, in this embodiment, in the line connection control system 1000 that controls the connection of a call line between terminals via at least one or more exchanges or relay stations, the exchange 200 or relay station 100 includes a first communication unit (e.g., IP call communication unit 2011) that receives a voice signal from a terminal (e.g., terminals T1, T2) connected to the exchange 200 or relay station 100, a second communication unit (e.g., trunk line call communication unit 2012) that transfers the voice signal to another exchange or relay station different from the above-mentioned exchange or relay station, and a setting table (e.g., , setting table 211), it is determined whether or not to transfer the voice signal to the other relay station or exchange, and if it is determined that the voice signal is to be transferred to the other relay station or exchange, the signal processing unit (e.g., multiplexing processing unit 202) does not perform a predetermined process on the voice signal (e.g., time division multiplexing or codec processing of the voice signal), and the second communication unit has a call control unit (e.g., call control unit 201) that transfers the voice signal to the other relay station or exchange along with the address of the device itself (e.g., the IP address of the exchange 200), so that it is possible to avoid voice delays while retaining route information. For example, after sending a call signal of a control signal for connecting a trunk line, if the IP forwarding setting is ON when a call is established, the address of the device itself is notified to the forwarding destination and route information is retained, while the header information of the voice signal is rewritten and control is performed so that internal processing is not performed, and a call can be made between terminals without causing a voice delay.

Conventionally, as shown in FIG. 6, when a peer-to-peer connection is adopted as a communication method to prevent voice delay, communication is possible without delaying the voice signal R11 because the signal is not taken into the exchange 600A, relay station 600C, and exchange 600B. However, the exchange 600A, relay station 600C, and exchange 600B cannot grasp the route information, and it is difficult to grasp the faulty part. Also, as shown in FIG. 7, in the case of a VoIP connection, all voice signals are taken into the exchange 700A, relay station 700C, and exchange 700B, and are transmitted after undergoing internal processing D1 to D6 on the voice signals, such as time division multiplexing and codec processing, so voice delay occurs in the voice signals R21 to R24, and the delay becomes more noticeable the more intervening exchanges and relay stations there are. According to this embodiment, these problems can be solved as described above.

The present invention is not limited to the above-described embodiment, but includes various modifications.
For example, in the above embodiment, each exchange or relay station refers to a predetermined setting table and determines whether or not to set IP forwarding in S505 of FIG. 5. However, whether or not to set IP forwarding may be determined according to the number of exchanges or relay stations intervening in the communication path. For example, the call control unit 201 refers to the connection information received from the terminal T1 and the association table, determines whether or not the communication path to the terminal T2 has a predetermined threshold (for example, 5) or more relay stations, and when it determines that the number of relay stations is equal to or greater than the predetermined threshold, controls to turn on the IP forwarding setting from the relay station (for example, the sixth relay station) that is equal to or greater than the threshold. In this way, the call control unit determines whether or not to IP forward the voice signal according to the number of the exchanges or relay stations in the path to the terminal that is the call destination, and can, for example, perform internal processing without IP forwarding the voice signal at relay stations within an allowable range for voice delay, while switching and controlling to perform IP forwarding at subsequent relay stations so as not to cause voice delay.

Furthermore, for example, the call control unit 201 refers to the connection information received from the terminal T1 and the correspondence table, and determines whether or not it is necessary to go through a hierarchy (e.g., the second hierarchy) that is a predetermined threshold or higher in the communication path to the terminal T2. If it is determined that the hierarchy is a predetermined threshold or higher, it controls so that the IP forwarding setting is turned on from the relay station of the hierarchy that is above the threshold (e.g., the third hierarchy relay station). In this way, multiple exchanges or relay stations are connected by multiple hierarchies as shown in FIG. 1, and the call control unit determines whether or not to IP forward the voice signal depending on the number of hierarchies in the path to the terminal that is the call destination. In this way, for calls within a small area via a relay station in a low hierarchy where there is little possibility of a large voice delay, internal processing is performed without IP forwarding the voice signal, while for calls in a large area via a relay station in a high hierarchy where there is a high possibility of a large voice delay, the voice signal is IP forwarded to prevent voice delay.

Furthermore, the call control unit may control IP forwarding of the voice signal based on an operation from a terminal (for example, terminal T1). For example, when a user operating terminal T1 or terminal T2 feels that a voice delay has occurred in the call, these terminals may accept an operation from the user via an operation unit (for example, pressing a push button), and these terminals may send an operation signal based on the operation to the exchange, and the call control unit 201 of the exchange that receives the operation signal may turn on the IP forwarding setting of its own device. Furthermore, the exchange that has turned on the IP forwarding setting may send information to the exchange or relay station on the communication path to which the call is to be forwarded that the IP forwarding setting is to be turned on, and the call control unit 201 of the exchange or relay station on the communication path to which the call is to be forwarded may turn on the IP forwarding setting of its own device. In this way, by making it possible to select and set the IP forwarding setting of the exchange or relay station on the communication path between the terminals at the user's initiative, it becomes possible to make calls at speeds that meet the needs of various users who have different perceptions of call speed.

Furthermore, whether or not to turn on the IP forwarding setting may be set according to the telephone number of the terminal T2 to be connected. For example, the call control unit 201 of the exchange may determine whether or not the telephone number received from the terminal T1 is a predetermined telephone number (for example, the telephone number of a company executive with a high position or the telephone number of an important customer), and if it is determined that the telephone number is the telephone number, control may be performed to turn on the IP forwarding setting. In this case, the IP forwarding setting may be sequentially set by the call control unit 201 of the exchange or relay station on the communication path to be the forwarding destination, as in the case where the terminal accepts an operation via the operation unit. In this way, the call control unit determines whether or not the telephone number of the terminal to be called (for example, terminal T2) is a predetermined telephone number, and if it determines that the telephone number is a predetermined telephone number, it is possible to select whether or not to turn on the IP forwarding setting according to the other party of the call, for example, by controlling the IP forwarding of the voice signal, and in the case of an important customer or a high-ranking person, it is possible to make a call at a speed that does not cause voice delay.

1000 Line connection control system 100 Relay station 101 Call control unit (relay station)
1011 First relay line speech communication unit (relay station)
1012 Second relay line speech communication unit (relay station)
102 Multiplexing processing unit (relay station)
111 Setting table (relay station)
200 Exchange 201 Call control unit (exchange)
2011 IP telephone communication unit (switchboard)
2012 Trunk line communication unit (switchboard)
202 Multiplexing processing unit (switch)
211 Setting table (switchboard)
T1, T2 Terminals N12, N23, N34 Network

Claims (5)

A line connection control system for controlling connection of a call line between terminals via at least one exchange or relay station, comprising:
The exchange or relay station includes:
a first communication unit for receiving a voice signal from a terminal connected to the exchange or relay station;
a second communication unit for transferring a voice signal to another exchange or relay station different from the exchange or relay station;
a call control unit that determines whether or not to forward the voice signal received by the first communication unit to the other relay station or exchange based on a setting table that defines whether or not to perform IP forwarding on the voice signal, and when it is determined that the voice signal is to be forwarded to the other relay station or exchange, causes the second communication unit to forward the voice signal to the other relay station or exchange together with the address of the own device without performing a predetermined process on the voice signal by a signal processing unit;
having
The call control unit determines whether to IP forward the voice signal depending on the number of the exchanges or relay stations on a path to a destination terminal.
2. A line connection control system comprising: A line connection control system for controlling connection of a call line between terminals via at least one exchange or relay station, comprising:
The exchange or relay station includes:
a first communication unit for receiving a voice signal from a terminal connected to the exchange or relay station;
a second communication unit for transferring a voice signal to another exchange or relay station different from the exchange or relay station;
a call control unit that determines whether or not to forward the voice signal received by the first communication unit to the other relay station or exchange based on a setting table that defines whether or not to perform IP forwarding on the voice signal, and when it is determined that the voice signal is to be forwarded to the other relay station or exchange, causes the second communication unit to forward the voice signal to the other relay station or exchange together with the address of the own device without performing a predetermined process on the voice signal by a signal processing unit;
having
The plurality of said exchanges or relay stations are connected by a plurality of hierarchical layers,
The call control unit determines whether to IP forward the voice signal depending on the number of layers in a path to a destination terminal.
2. A line connection control system comprising: The call control unit determines whether or not a telephone number of a terminal to be a call destination is a predetermined telephone number, and when it is determined that the telephone number is the predetermined telephone number, performs IP forwarding of the voice signal.
2. The line connection control system according to claim 1. A line connection control system for controlling connection of a call line between terminals via at least one exchange or relay station, comprising:
The exchange or relay station includes:
a first communication unit for receiving a voice signal from a terminal connected to the exchange or relay station;
a second communication unit for transferring a voice signal to another exchange or relay station different from the exchange or relay station;
a call control unit that determines whether or not to forward the voice signal received by the first communication unit to the other relay station or exchange based on a setting table that defines whether or not to perform IP forwarding on the voice signal, and when it is determined that the voice signal is to be forwarded to the other relay station or exchange, causes the second communication unit to forward the voice signal to the other relay station or exchange together with the address of the own device without performing a predetermined process on the voice signal by a signal processing unit;
having
The call control unit performs IP forwarding of the voice signal based on an operation from the terminal.
2. A line connection control system comprising: A line connection control method carried out in a line connection control system that controls connection of a call line between terminals via at least one exchange or relay station, comprising:
The exchange or relay station includes:
receiving a voice signal from a terminal connected to said exchange or relay station;
determining whether to forward the voice signal to another relay station or exchange different from the exchange or relay station based on a setting table that defines whether to perform IP forwarding of the received voice signal;
When it is determined that the voice signal is to be transferred to the other relay station or exchange, a predetermined process is not performed on the voice signal by a signal processing unit, and the voice signal is transferred to another relay station or exchange other than the exchange or relay station together with the address of the own device ,
determining whether to IP forward the voice signal depending on the number of the exchanges or relay stations in a path to a destination terminal;
2. A line connection control method comprising:

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