JP4158415B2 - Communication control device and communication system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a communication system, and is suitable for application to, for example, dial-up connection to an ISP (Internet Service Provider) network via an existing public telephone network.
[0002]
The present invention also relates to a communication control device that is a component of such a communication system.
[0003]
[Prior art]
The overall configuration of the communication system 10 including the conventional RAS (Remote Access Server) 13 is as shown in FIG. 3, and the connection sequence is as shown in FIG.
[0004]
In FIG. 3, since the Internet network 12 indicates the Internet in a broad sense, an ISP network that directly accommodates the RAS 13 is also included in the Internet network 12.
[0005]
In general, when a subscriber terminal (for example, 16) such as a personal computer is used to dial the telephone number of the access point of the ISP network with which the user (for example, U1) has a contract, the steps S10 to S12 in FIG. The public telephone network 11 is connected to the RAS 13 by a public network switch (which is often different from 14).
[0006]
When an incoming call is received at RAS 13, a connection of the line is established by the negotiation of steps S13 to S15 by RAS 13 with a connection device (modem, TA) (not shown) on the subscriber terminal 16 side (S16). 15, user authentication is performed using the user ID and password of the user U 1, and if the authentication is successful (S 19, S 20), the RAS 13 responds to the IP address request (S 21) from the connected device (modem, TA) side. An IP address is assigned (S22).
[0007]
As a result, the user U1 can obtain an IP address and establish a PPP connection (S23, S24), so that the subscriber terminal 16 can access the Internet 12 (S25).
[0008]
If such a dial-up connection is used, even a user who has not been assigned a fixed IP address can easily access the Internet 12.
[0009]
Note that the RAS 13 used here is generally a RAS based on a UNI connection connected to a subscriber line.
[0010]
[Problems to be solved by the invention]
However, in such dial-up connection, the telephone line of the public telephone network 11 is used, so that the user (for example, U1), in addition to the service provision fee for the Internet connection service provided by the ISP, You have to pay a telephone fee (call charge) for using the line.
[0011]
Various fee schemes are adopted for each ISP provider, such as the flat rate system that does not depend on connection time and the pay-per-use system that depends on connection time. However, there are differences in the charge system according to the telephone carrier.
[0012]
However, in general, the telephone fee rate structure increases according to the communication time and increases according to the distance category. It has a meaning equivalent to the pay-as-you-go system). The distance classification is a classification of the communication distance between two points (for example, the distance between the subscriber terminal 16 and the RAS 13). Even when the communication time is the same, the longer the communication distance, the higher the telephone fee. .
[0013]
For this reason, the user U1 bears a higher telephone fee as the time for accessing the Internet 12 becomes longer and as the communication distance between the subscriber terminal 16 and the RAS 13 becomes longer.
[0014]
From the standpoint of an ISP operator, as many RASs 13 as possible are distributed over a wide geographical area (for example, in units of municipalities), the communication distance from any user is shortened. This means that it is difficult to obtain contracts with many users unless efforts are made to lower the telephone charges paid by the users.
[0015]
However, in order to realize such a distributed arrangement of RAS, it is necessary to purchase a new RAS to be placed at a base where RAS has not been placed so far, so that the cost of the RAS facility itself is newly generated. In order to connect the RAS to the exchange of the public telephone network 11, the ISP operator pays the telephone operator a connection fee (exchange connection fee) and the space for installing the RAS is distributed over a wide geographical area. Charges to secure (installation space charges), maintenance costs, etc. will lead to new cost increases.
[0016]
In addition, if the distributed arrangement is used, there is a high possibility that the use efficiency of one RAS will decrease, and the number of lines for connecting the RAS and the public telephone network switch as a whole increases. It will be reduced and the system will become inefficient.
[0017]
Therefore, if RAS is easily distributed and distributed, it will eventually cover a new cost burden due to an increase in the service provision fee, and there is a possibility of losing even a user with a short communication distance before performing the distributed arrangement. is there.
[0018]
[Means for Solving the Problems]
In order to solve such a problem, in the first invention, For VoIP Corresponding to the communication protocol of VoIP In a communication control apparatus for performing communication of control signals such as call setting for a network, (1) VoIP Network and , Next to it Existing telephone network and local area network For multiple gateway devices placed between VoIP Correspondence management means for managing the correspondence between identifiers on the network and telephone numbers; (2) of the telephone numbers managed by the correspondence management means; B Representative number designating means for designating a representative number of an access server centralized exchange accommodating one or a plurality of remote access servers that accept incoming calls to the local area network; (3) previous Existing power When an incoming request signal containing the representative number for requesting an incoming call to the local area network is received from a communication terminal on the speech network, The existing telephone network and the access server aggregation switch side; Call management means for managing the call by communicating the control signal; (4) the communication terminal; Housed in the access server aggregation switch To communicate information signals between remote access servers, VoIP A first gateway device located between the network and the existing telephone network; VoIP Routing provision means for determining a transmission path for connecting a network and a second gateway device arranged between the local area networks is provided.
[0020]
In addition 2 In the present invention, in the communication system that performs dial-up connection from a communication terminal to a predetermined local area network, (1) control signal communication is performed. 1st invention A communication control device of (2) For VoIP Corresponding to the communication protocol of VoIP An existing telephone network adjacent to the network via a first gateway device; (3) VoIP A local area network adjacent to the network via a second gateway device; and (4) an incoming call request containing a telephone number for requesting an incoming call from the existing telephone network to the local area network. When the signal is transmitted, the subscriber exchange on the existing telephone network supplies the incoming call request signal to the communication control device, and the communication control device responds to the telephone number accommodated in the incoming call request signal. Routing processing for determining the transmission path of the information signal between the first gateway device and the second gateway device. When there are a plurality of remote access servers, an access server centralized exchange accommodating one or a plurality of remote access servers is interposed between the second gateway device and these remote access servers, and the access server The central switch exchanges one of a plurality of remote access servers by supplying the incoming request signal. It is characterized by that.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
(A) Embodiment
Hereinafter, embodiments of a communication control device and a communication system according to the present invention will be described.
[0022]
In this embodiment, not only a public telephone network where a telephone fee is charged but also a VoIP (Voice over IP) network that does not incur a telephone charge (or low), the incoming call to the RAS is performed when dial-up IP connection is established. It is characterized by keeping telephone charges low. Even if the communication distance from the user's home to the RAS is long, if the majority of the communication distance is consumed by the VoIP network, dial-up IP connection can be performed simply by paying a telephone fee corresponding to the shortest communication distance. it can.
[0023]
There are cases where the communication fee for performing communication on the VoIP network is free and charged. However, even if there is a charge, generally, the distance classification does not exist, and communication is possible even when the communication distance is long or short. If the time is the same, the communication fee is the same amount. In addition, this communication charge is normally suppressed to a low charge equal to or less than the distance classification corresponding to the shortest communication distance (in the case of a local call) among the telephone charge distance classifications.
[0024]
(A-1) Configuration of the embodiment
An example of the overall configuration of the communication system 20 of the present embodiment is shown in FIG.
[0025]
In FIG. 1, the communication system 20 includes public telephone networks 11 and 27, an Internet network 12, RAS 13 </ b> A to 13 </ b> C, a RAS aggregation switch 26, and a VoIP network 21.
[0026]
Among them, the subscriber exchange 14 in the public telephone network 11 operated by the telephone carrier performs a function of accommodating a subscriber line for directly connecting a telephone or a FAX, a function of connecting to the MG 22, and a common line connection. For example, subscriber terminals 16 and 17 are accommodated in the subscriber line. A VoIP network 21 is interposed between the public telephone network 11 and the Internet network 12, and an MG (media gateway) 22 is disposed between the public telephone network 11 and the VoIP network 21, and the VoIP network 21 and the Internet. An MG 24 is arranged between the network 12.
[0027]
A subscriber terminal (for example, 16) is a subscriber of a telephone service provided by a telephone company, and is connected to a personal computer operated by a person (for example, U1) who has concluded a contract with the ISP company, or a connection It consists of equipment (modem, TA, etc.).
[0028]
The VoIP network 21 is a LAN (local area network) that is constructed and operated by a VoIP provider to provide a VoIP telephone service, and is an IP network used for VoIP.
[0029]
The MG is also called a VoIP gateway, and is a device for exchanging voice data between a telephone network (for example, 11) and an IP network (for example, 21). VoIP originally refers to a technology for carrying voice data on a TCP / IP network for an IP phone or the like. In this embodiment, the VoIP network 21 is used as a relay network for Internet connection.
[0030]
Therefore, in this embodiment, the information data transmitted for the subscriber terminal (for example, 16) on the VoIP network 21 is not narrowly defined voice data, but an HTML file or image describing a Web page or the like, for example. It is often a file or email.
[0031]
This information data is transmitted from the subscriber terminal (for example, 16) and transmitted in the upstream direction supplied to one of the RAS (for example, 13A) via the subscriber switch 14, MG22, MG24, and RAS aggregation switch 26. On the other hand, in the opposite direction, any one of the RAS (for example, 13A) supplies the RAS aggregation switch 26, MG24, MG22, the subscriber switch 14 and the subscriber terminal (for example, 16) in the downstream direction. May be transmitted. In any case, the identifier used for specifying the communication partner on the public telephone network 11 is a telephone number, and the identifier used for specifying the communication partner on the VoIP network 21 is an IP address (in some cases, MAC address is also available).
[0032]
MG22-MG 24 The VoIP network 21 that accommodates the CA 25, etc. is constructed by a VoIP operator. The VoIP operator uses the MG 22 for convenience of a call between the IP telephone and the existing telephones on the public telephone networks 11 and 27. MG 22 is distributed over a wide geographical area, so that MG 22 is connected to a subscriber terminal (for example, 16) or subscriber switch 14 at a position with a short communication distance (for example, a local call). There is a high possibility of being installed at a possible position.
[0033]
A RAS (Remote Access Server) can generally connect to a LAN (that is, a dial-up connection) by using a telephone line from a place not connected to a LAN (here, an ISP network) by accepting an incoming call. Often referred to simply as an access server. The RAS has a function of performing dial-up PPP connection by a modem and TA and a function of assigning an IP address.
[0034]
Here, an ISP network operated by an ISP company, that is, an AS (autonomous system) is assumed as the LAN connected by dial-up. This ISP network is the LAN 1 included in the Internet network 12 in FIG.
[0035]
As RAS, there are cases where a connection device (modem or TA) is connected to an ordinary personal computer and used as RAS, and there are cases where a RAS dedicated machine is used. Although the number of connected devices that can be used is usually one, in the case of using a RAS dedicated device, a single device can accommodate a plurality of connected devices and can receive more incoming calls simultaneously.
[0036]
In the example of FIG. 1, the authentication servers 15A to 15C are included in the RAS 13A to 13C, but a dedicated authentication server may be provided separately from the RAS. When a dedicated authentication server is provided, the RADIUS protocol may be used for communication between the RAS and the authentication server.
[0037]
The authentication servers 15A to 15C are servers that perform user authentication, and have been accessed by verifying whether the user ID and password supplied from the user (for example, U1) match those registered in advance. Validate the user's legitimacy. In order for the ISP network LAN1 to accept a dial-up IP connection by an incoming user, this authentication result needs to be positive.
[0038]
In the ISP network LAN1, there are various servers and network devices such as a mail server, DNS server, Web server, many routers, and firewalls, in addition to the RAS 13A to 13C and the authentication servers 15A to 15C that are aggregated in one place. Usually it exists.
[0039]
If the authentication results by the authentication servers 15A to 15C are affirmative, the user (for example, U1) can use services provided by various servers in the ISP network LAN1, and can also use the ISP network LAN1. Via these, services provided by various servers on the Internet network 12 outside the ISP network LAN 1 can be used.
[0040]
The RAS central exchange 26 that accommodates the RAS 13A to 13C basically has the same function as a normal telephone exchange, but manages the TN1 that is a telephone number (representative number) representing the RAS 13A to 13C. When a call setting message (IAM message) including the representative number TN1 as an incoming call number information element for designating an incoming call destination is supplied from the CA 25 described later, the incoming call is distributed to the RAS 13A to 13C according to a predetermined distribution procedure.
[0041]
Various procedures can be used as the distribution procedure. For example, a round robin method for switching the RAS to be called according to a predetermined order, a crossbar method, or the like may be used.
[0042]
When the distribution destination RAS is determined according to the distribution procedure (here, it is determined that the RAS 13A is determined), the RAS central exchange 26 makes an incoming call to the RAS 13A.
[0043]
Therefore, the function of the RAS 13A itself for receiving an incoming call may be exactly the same as that of the conventional RAS 13 shown in FIG. 3, and the RAS already installed in the ISP network LAN 1 is used as it is for the present embodiment. It is also possible.
[0044]
The CA (call agent (external call control element)) 25 has an internal configuration shown in FIG. 5, for example.
[0045]
In general, the CA is not necessarily arranged with the MG, and there may be an MG without the CA (in this case, the MG itself has the CA function). However, providing a CA outside the MG as in this embodiment means that the MG itself does not have an intelligent function necessary for call setting (call management), routing, etc., and is basically on the public telephone network 11. Converting analog signals into digital signals and performing voice coding (if the information data to be sent is not voice data, the voice coding is omitted and transmitted transparently) It will only have the function to do the opposite process.
[0046]
Even when an external CA is involved, it is the MG that operates according to call setting and routing, but the specific contents of the call setting and routing, that is, the MG at which timing the call is set for which MG The physical link to which the generated IP packet is sent to be routed is substantially determined by the CA, and the MG only operates according to the control from the CA.
[0047]
(A-1-1) Call agent internal configuration example
In FIG. 5, the CA 25 includes a communication unit 30, an MTP processing unit 31, a control unit 32, a routing providing unit 33, an identifier correspondence management unit 34, and a call management unit 35.
[0048]
Of these, the communication unit 30 includes a port connected to the transmission path, and the control unit 32 is a CPU (central processing unit) of the CA 25.
[0049]
The MTP processing unit 31 is a part corresponding to a message transfer unit, that is, a MTP (Message Transfer Part) level 1/2/3 function communication protocol in the common line signal system hierarchy, and is common to the public telephone network 11 side. Control signals for call setting and the like are exchanged with a line signal network (not shown). Various methods can be considered as to what transmission path is used for the exchange of the control signal. For example, although it is conceivable to use transmission paths that pass through MG22 and MG24, in the present embodiment, transmission paths that do not pass through MG22 and MG24, such as transmission paths CD1 and CD2 indicated by dotted lines in FIG. Shall be used.
[0050]
The MTP level 1/2/3 is used for the exchange of control signals on the transmission lines CD1 and CD2. A signal relay station (STP) may be interposed on the transmission lines CD1 and CD2.
[0051]
Even when a control signal such as call setting is exchanged without using the transmission channels CD1 and CD2 via the MG22 and MG24, the information data is processed and transmitted by the MG. It is considered necessary to notify the MGs 22 and 24 from the CA 25 that a proper call setup has been performed to secure resources for processing and transmitting information data.
[0052]
As a communication protocol used when the CA 25 controls each MG, for example, MGCP can be used.
[0053]
In FIG. 1, the CA 25 is illustrated inside the VoIP network 21, but the CA 25 is independent of the VoIP network 21 in the same meaning that the telephone network and the common line signal network are independent within the public telephone network 11. It can also be seen that it is. In FIG. 1, only one CA 25 is shown, but a plurality of CAs may exist. In this case, a plurality of CAs constitute a network and exchange information regarding the control signal between the CAs, and each CA controls a separate MG. For example, the CA that controls the MG 22 and the CA that controls the MG 24 are separate.
[0054]
However, in the example of FIG. 1, since CA is only CA25, CA25 controls all of MG22 to MG24.
[0055]
The functions of MTP levels 1 to 3 of the MTP processing unit 31 correspond to the physical layer (layer 1), data link layer (layer 2), and network layer (layer 3) of the OSI reference model, respectively.
[0056]
Of these, MTP level 1 corresponding to layer 1 of the OSI reference model is a level corresponding to physical / electrical characteristics of the signal data link and its utilization means, and MTP level 2 corresponding to layer 2 is on the individual signal data link. MTP level 3 corresponding to layer 3 is a level corresponding to a function for analyzing and determining a signal transfer route. With the MTP level 3 function, signal routing can be controlled according to the state of the signal network.
[0057]
However, since what is called “signal” here is a so-called control signal (for example, a message for setting or disconnecting a call), information data (for example, an HTML file constituting a Web page, The contents of the e-mail, etc.) are transmitted on the VoIP network 21 (for example, between MG22 and MG24) according to a route that does not pass through the CA25. However, the route is determined according to the routing provided by the CA 25.
[0058]
The identifier correspondence management unit 34 is a database that stores and manages the correspondence between telephone numbers and IP addresses.
[0059]
For example, if the IP address PA1 serving as the identifier of the MG 24 on the VoIP network 21 and the representative number TN1 are associated in this database, the control unit 32 will receive the incoming call number information element contained in the call setting message. By searching the database using the representative number TN1 generated from the search key as a search key, the IP address PA1 can be obtained as a search result.
[0060]
The control unit 32 has a number translation function, and the received number information element corresponding to the number dialed by the user U1 (by the subscriber terminal 16) is the RAS connection request number RC1 (here, the representative) If the RAS connection request number RC1 is used as a search key, the identifier correspondence management unit 34 performs a search.
[0061]
The routing providing unit 33 is a part that provides the above-described routing related to transmission of the information data and control signal, and determines a route from the MG 22 to the MG 24 based on the IP address PA1 obtained as a search result. Then, a control command for realizing the route on the VoIP network 21 is transmitted to the MG 22 or MG 24.
[0062]
The call management unit 35 is a part that manages various types of information related to calls such as call setting and call disconnection.
[0063]
In addition to the MGs 22 to 24 and the CA 25, there are a large number of network devices such as routers (not shown) on the VoIP network 21, and for example, a route connecting the MG 22 and the MG 24 passes through these routers.
[0064]
The public telephone network 27 is a public telephone network similar to the public telephone network 11.
[0065]
Hereinafter, the operation of the present embodiment having the above configuration will be described with reference to the connection sequence of FIG. This connection sequence is composed of steps S30 to S52.
[0066]
In FIG. 4, Setup, Call Proc (Call Proceeding), and Connect are ITU-T recommendation H.264. Q.323 most commonly used in H.323 compliant networks. It is a message (control signal) group corresponding to the 931 call control message.
[0067]
Also, IAM (Initial Address Message), ACM (Address Complete Message), and ANM (Answer Message) correspond to ISUP call control messages corresponding to the ISUP (ISDN User Part) protocol defined for interworking with ISDN. Message (control signal) group.
[0068]
(A-2) Operation of the embodiment
Here, the operation will be described by taking as an example a case where a user U1 contracted with an ISP operator who operates the ISP network LAN1 makes a dial-up connection to the ISP network LAN1 using the subscriber terminal 16 shown in FIG. .
[0069]
In FIG. 4, when the user U1 (subscriber terminal 16) dials a predetermined service number, the subscriber terminal 16 supplies the Setup message requesting call setup to the subscriber exchange 14 (S30). The subscriber exchange 14 supplies an IAM message requesting call setting to the CA 25 via the transmission line CD1 (S31).
[0070]
The service number includes a VoIP provider number VN1 that is a number that designates a VoIP provider, and a RAS connection request number RC1 that is a number that requests dial-up IP connection via the ISP network LAN1.
[0071]
Among the service numbers (VN1 + RC1), the subscriber exchange 14 can specify the MG 22 as a return path for information data or the like based on the VoIP carrier number (VN1). When voice signals on the public telephone network 11 that cannot originally be exchanged on the IP network are exchanged on the VoIP network 21, the MG 22 needs to encapsulate these signals in IP packets and perform tunneling.
[0072]
Upon receiving the IAM message in step S31, the CA 25 obtains the IP address PA1 of the MG 24 from the identifier correspondence management unit 34 using the RAS connection request number RC1 (representative number TN1) in the service number as a search key.
[0073]
Then, the routing providing unit 33 determines a route between the MG 22 and the MG 24 according to the IP address PA1 based on various information such as a routing table, and realizes the route on the VoIP network 21. A control command for transmitting to the MG 22 or MG 24 is transmitted.
[0074]
Both the Setup message and the IAM message are control signals for requesting call setup, and include a called number information element for designating a destination. The 931 call control message is different in that the IAM message is an ISUP call control message.
[0075]
After supplying the IAM message to the CA 25, the subscriber exchange 11 returns a Call Proc message to the subscriber terminal 16 (S33). The Call Proc message is a control signal notifying that the call establishment procedure has been started.
[0076]
After receiving the IAM message in step S31, the CA 25 returns the ACM message to the subscriber switch 14 (S34), and supplies the IAM message to the RAS aggregation switch 26 (S35). This ACM message is a control signal that indicates that the caller of the called party is ringing.
[0077]
Upon receiving the IAM message in step S35, the RAS aggregation exchange 26 returns an ACM message to the CA 25 (S36), and supplies a Setup message to any one of the RAS 13A to 13C (S37). At this time, the destination RAS that supplies the Setup message is determined according to the above-described distribution procedure. In FIG. 4, as an example, it is assumed that RAS 13A is determined as the destination.
[0078]
Note that, between steps S35 and S36, the RAS aggregation switch 26 determines whether the RAS 13A to 13C on the receiving side is busy, and if all the lines of the RAS 13A to 13C are in use, the ACM message Instead it will return busy.
[0079]
The RAS 13A that has received the Setup message in step S37 sends a Call Proc message to notify that the call establishment procedure has been started internally, and a Connect message to notify that the call has been answered. Each is returned to the RAS central exchange (S38, S39).
[0080]
Upon receipt of the Connect message, the RAS aggregation switch 26 returns an ANM message to the CA 25 to notify that the called party has answered the call (S40). The ANM message is the same as the Connect message in that it is a control signal for notifying that the call has been answered. This is a 931 call control message, and the ANM message is an ISUP call control message.
[0081]
The CA 25 that has received the ANM message in step S40 returns the ANM message to the subscriber exchange 14 (S41).
[0082]
Following the step S41, when a Connect message is returned from the subscriber exchange 14 to the subscriber terminal 16 (S42), an LCP (Link Control Protocol) is activated and the data link is established between the subscriber terminal 16 and the RAS 13A. A layer is established (S43). During this time, negotiation via MG22 and MG24 is performed between the connected device (modem, TA, etc.) connected to the subscriber terminal 16 and the RAS 13A, and the communication speed, correction method, compression method, etc. are determined and stable. Communication is possible.
[0083]
The LCP is a protocol that is a component of a PPP (Point-to-Point Protocol) protocol. PPP is an aggregate of a plurality of protocols, and in addition to the LCP, NCP (Network Control Protocol), PAP (Password Authentication Protocol), CHAP (Challenge Handshake Authentication Protocol), and the like are constituent elements. Of these, the NCP is a part depending on the upper protocol, and when the upper protocol is TCP / IP as in the present embodiment, it becomes IPCP (IP Control Protocol).
[0084]
After the data link layer is established in step S43, a password, a user ID, and the like are transmitted from the subscriber terminal 16 to the RAS 13A to make an authentication request (S44). This authentication request is a process corresponding to the PAP or CHAP. In the case of PAP, a plain text password is transmitted, and in the case of CHAP, an encrypted password is transmitted. At least in the case of CHAP, exchange of information necessary for encryption occurs. Therefore, the communication in step S44 from the subscriber terminal 16 toward the RAS 13A as shown in the figure is not sufficient. Communication is required.
[0085]
The password and user ID received by the RAS 13A are passed to the authentication server 15A (S45) for authentication. If the validity of the user U1 is recognized and a positive authentication result is passed from the authentication server 15A to the RAS 13A, a positive authentication response is returned from the RAS 13A to the subscriber terminal 16A (S47).
[0086]
Upon receiving this authentication response, the subscriber terminal (modem, TA) 16 sends a request corresponding to the IPCP to the RAS 13A to request an IP address assignment (S48), and the RAS 13A notifies the IP address. The request is met (S49). In the case of a so-called terminal type dial-up connection used by many individual users, an arbitrary IP address that is not used at that time is assigned. Therefore, each time a dial-up connection is made, a different IP address is assigned. However, in the case of LAN type (network type) dial-up connection, a predetermined IP address is assigned.
[0087]
The notification of the IP address (IP address assignment) is also a process corresponding to the IPCP.
[0088]
By assigning the IP address in step S49, a network layer is established (S50), and a PPP link is established (P51).
[0089]
As a result, the subscriber terminal 16 can transmit and receive the information data via the MG 22 and the MG 24 with a host (for example, a mail server) on the Internet network 12 including the RAS 13A. S52).
[0090]
(A-3) Effects of the embodiment
As described above, according to the present embodiment, the cost can be reduced and high efficiency can be obtained in dial-up connection.
[0091]
Specifically, in addition to a public telephone network that uses a time-based charge system by distance, a dial-up connection is made with a VoIP network that is free of charge or has a uniform charge system that does not depend on the communication distance. Thus, the telephone charge burden can be suppressed on the user (for example, U1) side, and on the ISP business side, the cost of the new RAS equipment itself, the exchange connection fee, the installation space fee, the maintenance management cost Etc. can be suppressed.
[0092]
Compared to the case where the RAS distributed arrangement described above is performed, in the present embodiment, it is possible to improve the RAS utilization efficiency and the line utilization rate by performing RAS base aggregation, which greatly contributes to this suppression.
[0093]
(B) Other embodiments
In the above embodiment, the connection form of the RAS central exchange 26 and the RAS 13A to 13C is a UNI connection, but this can also be an NNI connection.
[0094]
In the above embodiment, the case of connecting to the Internet via the ISP network has been described as an example. However, the present invention is not limited to this case, and can be widely applied when RAS is used.
[0095]
For example, an intranet of a general company can be accessed via an existing telephone network (including a PHS network) separately from a DMZ (unarmed segment) for connecting to the Internet via a firewall, etc. Although a RAS is often prepared, there are many advantages to this RAS, such as a reduction in telephone charges, if connection is made via the VoIP network as described above.
[0096]
In the above-described embodiment, the MG performs call setting and routing in accordance with control from an external CA. However, the MG itself may incorporate call setting and routing functions.
[0097]
Further, in the above embodiment, the terminal (for example, 16) is connected to the public telephone network 11 and further connected to the VoIP network 21 to receive incoming calls to the RAS. And the VoIP network 21 need not necessarily be arranged in this order. That is, a dial-up IP connection may be established by connecting a terminal to the VoIP network 21 and further receiving a call to the RAS via the public telephone network 11. This is basically the same procedure as when calling by calling from an IP telephone (corresponding to the terminal) on the VoIP network 21 to an existing telephone (corresponding to RAS in this case) on the public telephone network 11.
[0098]
Further, dial-up connection is not necessarily a concept limited to the case of connecting to the Internet, and therefore the present invention can also be applied to a case where dial-up connection is performed to a LAN that is not connected to the Internet.
[0099]
In the above-described embodiment, three RAS 13A to 13C are shown. However, the number of RAS in one ISP network may be smaller or larger than three.
[0100]
In the above embodiment, only the MG 22 is shown as the MG for connecting the VoIP network 21 and the public telephone network 11, but it is natural that the MG 22 may be connected by a plurality of MGs. In dial-up connection, the communication distance on the public telephone network 11 (for example, the communication distance between the subscriber terminal 16 and the MG 22) is shortened as much as possible, and the communication distance on the VoIP network 21 (for example, the communication distance between the MG 22 and MG 24) is increased. Therefore, it is desirable that the number of MGs connecting the public telephone network 11 and the VoIP network 21 is as large as possible and geographically distributed.
[0101]
Furthermore, in the above embodiment, the relationship between the public telephone network 11 and the VoIP network 21 has been mainly described. However, the relationship between the VoIP network 21 and another public telephone network (one of which is 27) is the same as in the above embodiment. It is. Further, the public telephone network 27 is a part of the public telephone network 11, and can be regarded as an MG in which the MG 22 and the MG 23 are arranged geographically dispersed.
[0102]
In the above embodiment, there is one ISP network LAN1 connected to the VoIP network 21, but it is natural that a plurality of ISP networks may be connected to one VoIP network.
[0103]
In the above embodiment, all RAS 13A to 13C in one ISP network LAN1 are connected to one VoIP network 21, but each RAS in one ISP network may be connected to a different VoIP network. It is natural to be good.
[0104]
In the above embodiment, control signals are exchanged through the transmission paths CD1 and CD2 that do not pass through the MG. However, control signals may be exchanged through a transmission path that passes through the MG.
[0105]
However, for the purpose of the common line signal system in which a control signal is transmitted and received using a dedicated signal line separately from the telephone line, even if a transmission path via MG (for example, MG22) is set, control is performed. It is desirable to secure physical resources related to the MG 22 for signal transmission (transmission bandwidth, CPU processing capacity, etc.) as completely independent from physical resources for information data transmission.
[0106]
In the above description, the present invention is realized mainly by hardware, but the present invention can also be realized by software.
[0107]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a highly efficient communication system and communication control device with reduced costs.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an example of the overall configuration of a communication system according to an embodiment.
FIG. 2 is a connection sequence of a conventional communication system.
FIG. 3 is a schematic diagram showing an example of the overall configuration of a conventional communication system.
FIG. 4 is a connection sequence of the communication system according to the embodiment.
FIG. 5 is a schematic diagram illustrating a configuration example of a main part of a CA (call agent) used in the communication system according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10,20 ... Communication system 11, 27 ... Public telephone network, 12 ... Internet network, 13, 13A-13C ... RAS, 14 ... Subscriber switch, 15, 15A-15C ... Authentication server, 16, 17 ... Subscriber terminal 21 ... VoIP network, 22-24 ... MG, 25 ... CA, 26 ... RAS aggregation switch, 31 ... MTP processing unit, 33 ... routing providing unit, 34 ... identifier correspondence management unit, 35 ... call management unit.

Claims (2)

In a communication control apparatus that performs communication of control signals such as call setting for a VoIP network corresponding to a communication protocol for VoIP ,
And the VoIP network, every plurality of gateway devices is disposed between the existing telephone network and a local area network adjacent thereto, the corresponding relationship management means for managing an identifier on the VoIP network, a correspondence between the telephone number ,
Of the phone number to which the corresponding relationship managing means, representative number designation that specifies the previous representative number of the access server aggregation exchanges which accommodate one or more remote access server that accepts incoming call to kilometers over local area network Means,
From the communication terminal on the leading SL existing telephone network, when an incoming request signal containing the said representative number to request a call to the local area network has arrived, and the existing telephone network and the access server aggregation exchange side, Call management means for managing the call by communicating the control signal;
A first gateway device disposed between the VoIP network and an existing telephone network for communicating information signals between the communication terminal and a remote access server accommodated in the access server central switch; and the VoIP A communication control device, comprising: a routing providing unit that determines a transmission path for connecting a network and a second gateway device disposed between the local area network and the second gateway device. In a communication system that performs dial-up connection from a communication terminal to a predetermined local area network,
The communication control device according to claim 1 , which performs communication of a control signal;
An existing telephone network adjacent to the VoIP network corresponding to the communication protocol for VoIP via the first gateway device;
The local area network adjacent to the VoIP network via a second gateway device;
When the communication terminal transmits an incoming request signal containing a telephone number requesting an incoming call to the local area network from the existing telephone network, the subscriber exchange on the existing telephone network transmits the incoming request signal to the communication control. And the communication control device performs routing processing for determining a transmission path of the information signal between the first gateway device and the second gateway device in accordance with the telephone number accommodated in the incoming request signal. As well as
When there are a plurality of remote access servers, an access server central switch that accommodates one or a plurality of remote access servers is interposed between the second gateway apparatus and these remote access servers, and the access server central switch A communication system , wherein the incoming call is received by supplying the incoming request signal to one of a plurality of remote access servers .

Images