JP3875122B2 - Inter-network connection method, inter-network data communication system, and converter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a converter and a protocol conversion method for communicating packets between an ATM-SVC network and an IP network.
[0002]
[Prior art]
Conventionally, there is no known converter having a function of connecting an ATM-SVC network and an IP network and realizing packet communication.
[0003]
[Problems to be solved by the invention]
When the ATM-SVC network and the IP network are connected and the converter has a function of realizing packet communication, this converter needs a protocol conversion function for different network connections. Such a protocol conversion function is an ATM-SVC base and an IP base protocol conversion function in the lower layer of the protocol stack. If a single converter having such a conversion function is used, packet communication between different networks is possible. However, when a connection configuration is assumed, a plurality of converters are actually considered in consideration of reliability. Will be installed. However, when a plurality of converters are installed, there may occur a case where data cannot be connected to a specific converter that has ATM-SVC connection when a connection request is made.
[0004]
The present invention has been made in view of such a technical problem. When an ATM-SVC network and an IP network are connected, an incoming packet from the IP network is received by a specific converter connected to the ATM-SVC. It is characterized by providing a connection technique between an ATM-SVC network and an IP network that enables protocol communication and enables packet communication between different networks.
[0005]
[Means for Solving the Problems]
The inter-network connection method according to the first aspect of the present invention is such that each of a plurality of converters installed in a connection portion between an ATM-SVC network and an IP network establishes an SVC number and a destination IP when the SVC connection is established by itself. Storing the correspondence with the address, and transmitting correspondence information with the identification number of the own device and the destination IP address with which the SVC connection is established, to each of the plurality of converters, the transfer data from the other converter Storing the correspondence information between the converter identification number and the destination IP address with which the SVC connection has been established, and each of the plurality of converters sets the destination IP address for the packet data received at its own device. If the destination IP address is that the SVC connection has been established by the other converter with reference to the correspondence information, the incoming converter And when each of the plurality of converters receives the transfer of the incoming packet data from another converter, performs protocol conversion with the destination IP address as the end node address below the data link layer, and And sending to the end node address.
[0006]
The data communication system between different networks of the invention of claim 2 includes a plurality of converters installed at a connection portion between the ATM-SVC network and the IP network, and each of the plurality of converters has established an SVC connection by itself. Sometimes, the correspondence between the SVC number and the destination IP address is stored, and the correspondence information between the own device identification number and the destination IP address established by the SVC connection is transmitted to the other converter, and the transfer from the other converter. A function of receiving data and storing correspondence information between the converter identification number and the destination IP address established by the SVC connection; and checking the destination IP address of the packet data received at the own device, and the correspondence information To transfer incoming packet data to the other converter when the destination IP address is SVC connection established by the other converter with reference to FIG. A function of performing protocol conversion using the destination IP address as an end node address below the data link layer when receiving the transfer of the incoming packet data from another converter, and sending it to the corresponding end node address. It is what.
[0007]
According to a third aspect of the present invention, there is provided a converter for storing a correspondence between an SVC number and a destination IP address when an SVC connection is established by the own device, an identification number of the own device when the SVC connection is established by the own device, and Means for transmitting correspondence information with the destination IP address established by the SVC connection to another converter, correspondence information between the transfer data from the other converter and the identification number of the converter and the destination IP address established with the SVC connection. The destination IP address is checked with respect to the packet that has arrived at its own device and the packet received at its own device, and if it is the destination IP address for which the SVC connection has been established by the other converter with reference to the correspondence information, Means for transferring an incoming packet.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a functional configuration of a data communication system between different networks according to the first embodiment of this invention. The feature of the first embodiment is applied when adopting a method in which the destination IP address is an end node, and a converter (in this case, an ATM-SVC connection is always used for IP routing to the end address). Since it does not always go through the converter # 4), it has a function of transferring data to a specific converter # 4 connected to each converter # 1 to # 3 by SVC. In order to enable this data transfer function, each converter # 1 to # 4 has a function of notifying the other converter of the SVC connection and its destination address when the SVC connection is established with the own device, When this notification is received, it has a registration function for holding the information.
[0012]
First, as shown in FIG. 2, when the ATM network 1 and the IP network 2 are connected, it is necessary to perform protocol conversion. Therefore, a converter (CV) 4 that performs protocol conversion is installed in the connection part 3 between the networks.
[0013]
The connection form between the different networks 1 and 2 includes (1) an IP network that connects the local network mobile device 5 to the ATM network 1 when the user of the ATM network 1 roams out, and (2) There is an ATM network → IP network connection in which a roaming-in user of another network connects from the mobile device 6 of the other network to the IP network 2 as its own network. Therefore, the converter CV4 is required to have a protocol conversion function that can handle both of these connection forms.
[0014]
In FIG. 2, an ISP (Internet Service Provider) 11 is an Internet connection service provider. A GGSN (Gateway GPRS Support Node) 12 is a node that performs access control (connection notification, incoming call notification, etc.) with an ISP in each of an IP network and an ATM network. An SGSN (Serving GPRS Support Node) 13 is a subscriber node (or a visited node), and manages subscriber information of mobile subscribers in the area. The subscriber information is downloaded from an HLR (Home Location Register) when the mobile device is powered on. Then, the SGSN determines whether or not connection is possible based on the subscriber information when the mobile station makes and receives calls, and controls connection to the connection destination. A BG (Border Gateway) 14 is a gateway that controls connection between the different networks 1 and 2. The BG 14 is interposed between the GRX network 2A and the other company's IP network 2B in the same IP network 2.
[0015]
In order to enable smooth and reliable connection between the different networks 1 and 2, a connection system having redundancy as shown in FIG. 3 must be provided. That is, the BG 14 at the demarcation point 3 between the ATM network 1 and the IP network 2 is connected to the converter (CV) 4 of the ATM-SVC network 1, and the converter (CV) 4 is connected to the GGSN 12 and the SGSN 13 in the ATM network 1. To do. In consideration of the detour function at the time of failure, it is desirable to install a plurality of converters CV4. Here, DNS (Domain Name System) 15 is a domain name system, which is used on the Internet and converts a name designated by a user: APN (Access Point Name) to an IP address of a connection destination GGSN. is there.
[0016]
FIG. 4 shows the function of the converter (CV) 4 of the above embodiment. In the connection part 3 between the ATM network 1 and the IP network 2, a converter (CV) 4 is installed on the ATM network 1 side of the border gateway (BG) 14, and a user of the local network 1 uses the local network mobile device 5 to connect to the IP network 2. If roaming in, the CV4 sets the address of the destination node GGSN 12 or SGSN 13 and converts the protocol.
[0017]
FIG. 5 shows the functional configuration of the converter (CV) 4, which includes an ATM-SVC / IP network protocol converter 21, an ARF function / GMMS address converter 22, a GTP-Con protocol converter 23, and a converter (CV). A data transfer unit 24 and a data holding unit 25 are provided.
[0018]
The ATM-SVC / IP network protocol conversion unit 21 performs L1 / L2 protocol conversion between the ATM-SVC network 1 and the IP network 2. FIG. 6 shows the protocol stack. The protocol stack for packet data in the ATM network 1 is APL, GTP-U, UDP-IP, and ATM, and the protocol stack for packet data in the IP network 2 is APL, CTP-U, UDP-IP, and L1 / L1. In CV4, protocol conversion is performed between the L1 / L2 layer of the lowest layer and the ATM layer, but since the destination address of the end node is held, UDP-IP and GTP-U are stealed. Only.
[0019]
The ARF function (Access link Relay Function function) / GMMS address conversion unit 22 converts the ARF protocol and the standard DNS protocol. FIG. 7 shows the function. When the mobile device 5 of the own network roams to the other network 2, when the address cannot be resolved by the APN of the other network 2, it makes an inquiry to the ATM network 1 of the own network, and the IP address of the GGSN 12 is assigned to the other network 2 of the inquiry source. C. P. C. Reply with req. The IP address returned at this time is the IP address of the GGSM 12 of the end node.
[0020]
The GTP-C on protocol conversion unit 23 converts the GTP-C on SCCP protocol and the GTP-C on UDP-IP protocol. This conversion function is a function for converting the ARF protocol on the SCCP and the GTP-C signal into a UDP-IP signal and vice versa. The conversion between the IF protocol stack 31 and the DNS protocol stack 32 shown in FIG. Interconvert between.
[0021]
The inter-converter (CV) data transfer unit 24 creates correspondence information between the CV identification number and the destination address when the own CV establishes the SVC connection, holds the information in the data holding unit 25, and Notification of correspondence information of own CV number-destination address The inter-CV data transfer unit 24 also confirms the destination address of the received packet, refers to the correspondence management table data of the data holding unit 25, identifies the SVC connection CV number from the destination address, and applies the corresponding CV Forward incoming packets to
[0022]
The data holding unit 25 holds the correspondence data 26 of the CV identification number and the destination address when the own CV establishes the SVC connection, and the correspondence data of the SVC-CV number from the other CV notified from the other CV. Stored as correspondence management table data 27. These data are shown in FIG.
[0023]
FIG. 1 shows the CV-destination address correspondence management function of the data transfer unit 24 between converters (CV). (I) Each converter (here, CV # 4) creates correspondence information 26 between the CV identification number and the destination address at the time when the own CV # 4 establishes the SVC connection, and stores it in the data holding unit 25 To do. (Ii) At the same time, CV # 4 notifies the other CV # 1 to CV # 3 of the correspondence information of its own CV number-destination address. (Iii) Receiving the notification, each CV # 1 to CV # 3 stores the received CV number-destination address correspondence data in the data holding unit 25 of its own device as shown in the correspondence management table 27 shown in the figure. (Iv) For example, if a packet arrives at the CV # 3 from the other network 2 to the own network 1, the inter-CV data transfer unit 24 confirms the destination address and refers to the data in the address correspondence management table 27. The CV # 4 with which the SVC connection is established is specified, and the incoming packet is transferred. (V) The CV # 4 to which the packet is transferred refers to the destination address correspondence information 26 held in the data holding unit 25 and transmits the received packet to the corresponding SVC.
[0024]
FIG. 9 also shows a transfer process (corresponding to the processes (iv) and (v) in FIG. 1) by the inter-CV data transfer unit 24. Since the traffic 15 from the other network 2 toward the SGSN 13 of the own network 1 is IP-routed only considering the IP address of the SGSN 13 of the own network 1, it is not necessarily connected to the CV # 4 where the SVC connection is established. Therefore, if the CV # 3 in which the SVC connection is not established receives this packet data, the management table 27 of the data holding unit 25 of the own device is referred to, and the received data is the CV # 4 in which the SVC connection is established. It is transferred to.
[0025]
In this way, according to the inter-network data communication system and the inter-network connection method used by the first embodiment, the traffic 15 from the other network 2 toward the SGSN 13 of the own network 1 does not necessarily have the SVC connection. If a CV that is not connected to the established CV but has not established the SVC connection receives such packet data, the packet is transferred to the CV with the established SVC connection, so that packet communication can be seamlessly performed between different networks. In addition, the reliability of the system can be improved by providing a plurality of CVs. In addition, even if there are a plurality of CVs, packets from other networks can be identified as establishing an ATM-SVC connection. The CV can be reliably received.
[0026]
Next, a converter according to a second embodiment of the present invention and an inter-network connection method used by the converter will be described. FIG. 10 shows a functional configuration of the inter-network data communication system according to the second embodiment of this invention. A feature of the second embodiment is that a destination IP address is not an end node address but a converter address, and a converter (CV) replaces the destination IP address and the sender address.
[0027]
In the inter-network data communication system according to the second embodiment, a plurality of CVs are provided at the connection portion between the ATM network (own network) 1 and the IP network (other network) 2 in order to ensure system reliability. If installed, the IP network (other network) 2 may receive an incoming call from the other network 2 to the ATM network (own network) 1 in order to ensure that the incoming call is received by the CV having established SVC connection. The end address notified to the connection request of the SGSN 13 of the network 2 is set as a specific converter address, and then the specific CV receiving the incoming call uses the packet data from the other network 2 as the true destination IP address and the ARF inquiry. Then, it connects to the GGSN 12 or SGSN in its own network 1 that is the true end address.
[0028]
In order to enable this data communication function, the connection unit 3 between the ATM network (own network) 1 and the IP network (other network) 2 is connected as described above, as shown in FIG. A converter (CV) 4 having a function is installed. FIG. 11 shows the function of the converter (CV) of the second embodiment. In the connection part 3 between the ATM network (own network) 1 and the IP network (other network) 2, a CV 4 is installed on the ATM network 1 side of the border gateway (BG) 14. Then, when roaming in from the IP network (other network) 2, the CV 4 converts the destination IP address of the incoming packet to the CV 4 address and notifies the SGSN 13 of the partner network 2, and the packet addressed to its own address from the SGSN 13. Receive. Then, protocol conversion of the received packet data is performed, and the packet data is transmitted to the GGSN 12 of the regular IP address in the own network 1.
[0029]
FIG. 12 shows a functional configuration of the converter (CV) 4, which includes the same ARF function / GMMS address conversion unit 22 and GTP-Con protocol conversion unit 23 as those in the first embodiment, and the first embodiment. An ATM-SVC / IP inter-network protocol conversion unit 26 having a function different from the form, and a GTP-U, UDP-IP termination processing unit 27 and an IP address replacement unit 28 are provided as new functions.
[0030]
As in the first embodiment, the ARF function / GMMS address conversion unit 22 performs address resolution at the APN of the other network 2 when the mobile device 5 of the own network roams to the other network 2 as shown in FIG. If it is not possible, an inquiry is made to the ATM network 1 of its own network, and the IP address of the GGSN 12 is assigned to the other network 2 of the inquiry source. P. C. Reply with req. However, the IP address returned at this time is the IP address of CV4, unlike the first embodiment.
[0031]
As in the first embodiment, the GTP-C on protocol conversion unit 23 converts the GTP-C on SCCP protocol and the GTP-C on UDP-IP protocol as shown in FIG.
[0032]
The ATM-SVC / IP network protocol converter 26 in the second embodiment performs protocol conversion between the ATM-SVC network 1 and the IP network 2 as shown in FIG. The protocol stack for packet data in the ATM network 1 is APL, GTP-U, UDP-IP, and ATM, and the protocol stack for packet data in the IP network 2 is APL, CTP-U, UDP-IP, and L1 / L1. In CV4, protocol conversion is performed between the L1 / L2 layer of the lowest layer and the ATM layer. Further, in the second embodiment, the new GTP-U and UDP-IP termination processing unit 27 terminates UDP-IP and GTP-U, and the IP address re-sending unit 28 includes a destination IP address of packet data, Replace the sender IP address. These processes will be described in detail later.
[0033]
The inter-network connection method using the inter-network data communication system according to the present embodiment will be described with reference to FIG. (Xi) It is assumed that the local network mobile device D issues a transmission request in the IP network (other network) 2 with the GGSN 12 of the local network ATM network 1 as the destination IP address (APN = docomo.jp). (Xii) In response to this call request, the SGSN 13 (IP address #C) of the other network 2 requests address translation to the DNS 16 in the network, but (xiii) DNS 16 is in the network 2 The corresponding address cannot be found, and an unknown response is returned to the SGSN 13. When (xiv) receives this unknown response, it sends an inquiry to the ATM network 1. At this time, the destination IP address is APN = docomo. jp.
[0034]
(Xv) The converter (CV) 4 (the IP address is #B) of the ATM network 1 replies with its own IP address #B to the inquiry from the SGSN 13 of the other network 2.
[0035]
(Xvi) When the SGSN 13 of the other network 2 receives this #B address response, it sends a connection request to the ATM network 1 with the destination address being #B and the source address being #A. (Xvii) In response to this connection request, the converter (CV) 4 sends the original destination IP address APN = docomo. An address translation request is issued for jp, and (xviii) ARF 17 returns the address #A of the corresponding end node GGSN 12.
[0036]
(Xix) Upon receiving the address response #A from the ARF 17, the CV4 stores the correspondence between the self address #B and the end node address #A and issues a connection request to the GGSN 12 of the end node IP address #A. The GGSN 12 connects and (xx) notifies the CV4 when the connection is completed. (Xxi) Upon receiving the connection completion notification, the CV4 notifies the request source SGSN 13 of the other network 2 of the connection completion, and (xxii) the SGSN 13 notifies the source mobile device D of the connection completion. As a result, the mobile network D of the packet source and APN = docomo. A connection is established with the GGSN 12 of the own network 1 that manages jp.
[0037]
(Xxiii) Thereafter, the packet data transmitted from the mobile device D is delivered to the converter (CV) 4 as the packet data PK1 having the destination address #B and the source address #C in the SGSN 13, and the CV4 is the destination IP address. The IP address is replaced so as to become #A and the source address #B, and the packet data PK2 in the own network is transmitted to the GGSN 12 of the IP address #A. Conversely, the packet data PK3 (destination IP address #B, sender address #A) from the GGSN 12 is replaced with an IP address at CV4, and the packet data PK4 (destination IP address #C, sender address) #B) and transmit to the SGSN 13 of the other network 2.
[0038]
Thus, in the inter-network data communication system and the inter-network connection method used by the second embodiment, when the local network mobile device 5 roams into the local network 1 from the other network 2, a plurality of Even if the converter exists, it is possible to make a fixed incoming call to a specific converter that has established an SVC connection, and seamless roaming between different networks is possible. In addition, an economical network can be constructed by localizing a converter having a protocol conversion function at a connection part between different networks.
[0039]
【The invention's effect】
As described above, according to the present invention, in the case of connection between different networks, if a plurality of converters (CV) are installed in the connection part, the IP network which is the other network and the ATM-SVC network of the own network can be connected. Traffic destined for GGSN or SGSN is not necessarily connected to a CV with an established SVC connection, but if a CV with no established SVC connection receives such packet data, it is forwarded to the CV with an established SVC connection. Therefore, packet communication between different networks can be performed seamlessly, and the reliability of the system can be improved by providing a plurality of CVs. In addition, even if a plurality of CVs exist, packets from other networks can be obtained. Can be reliably received at a specific CV that has established an ATM-SVC connection.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an operation of an inter-network data communication system according to a first embodiment of this invention.
FIG. 2 is a block diagram showing a configuration of a data communication system between different networks according to the first and second embodiments of the present invention.
FIG. 3 is a block diagram showing a configuration on the ATM-SVC network side in the inter-network data communication system according to the first and second embodiments of the present invention.
FIG. 4 is an explanatory diagram of a data conversion operation by the inter-network data communication system according to the first embodiment of this invention.
FIG. 5 is a block diagram showing a functional configuration of a converter in the inter-network data communication system according to the first embodiment of this invention.
FIG. 6 is an explanatory diagram of protocol conversion processing performed by the converter used in the first embodiment of the present invention.
FIG. 7 is an explanatory diagram of APN → GMMS address resolution processing by the converter according to the first embodiment of the present invention.
FIG. 8 is an explanatory diagram of GTP-C on SCCP / GTP-C on UDP-IP conversion processing by the converter according to the first embodiment of the present invention.
FIG. 9 is an explanatory diagram of inter-converter data transfer processing by the converter according to the first embodiment of the present invention.
FIG. 10 is a block diagram showing the operation of the inter-network data communication system according to the second embodiment of this invention.
FIG. 11 is an explanatory diagram of a data conversion operation by the inter-network data communication system according to the second embodiment of this invention.
FIG. 12 is a block diagram showing a converter functional configuration in the inter-network data communication system according to the second embodiment of this invention.
FIG. 13 is an explanatory diagram of protocol conversion processing performed by a converter used in the second embodiment of the present invention.
[Explanation of symbols]
1 ATM-SVC network (own network)
2 IP network (other networks)
2A GRX network 2B Other company's IP network 3 Inter-network connection 4 Converter (CV)
5 Local network mobile device 6 Other network mobile device 11 Internet service provider (ISP)
12 GGSN
13 SGSN
14 BG (Border Gateway)
16 DNS
17 ARF
18 GMMS
21 ATM-SVC / IP network protocol conversion unit 22 ARF function / GMMS address conversion unit 23 GTP-C on protocol conversion unit 24 Inter-converter data transfer unit 25 Data holding unit 26 ATM-SVC / IP network protocol conversion unit 27 GTP -U, UDP-IP termination processing unit 28 IP address replacement unit

Claims (3)

Each of the plurality of converters installed in the connection portion between the ATM-SVC network and the IP network stores the correspondence between the SVC number and the destination IP address when the SVC connection is established in the own device, and Transmitting correspondence information between the identification number and the destination IP address with which the SVC connection has been established to another converter;
Each of the plurality of converters receiving transfer data from another converter and storing correspondence information between the identification number of the converter and a destination IP address established by the SVC connection;
Each of the plurality of converters checks the destination IP address of the packet data received at its own device, and if the SVC connection is established by another converter with reference to the correspondence information, Transferring incoming packet data to another converter;
When each of the plurality of converters receives the transfer of the incoming packet data from another converter, performs a protocol conversion in which the destination IP address is an end node address below the data link layer, and sends it to the corresponding end node address; A method for connecting between different networks. A plurality of converters installed at the connection between the ATM-SVC network and the IP network;
Each of the plurality of converters stores the correspondence between the SVC number and the destination IP address when the SVC connection is established in the own device, and the correspondence between the identification number of the own device and the destination IP address established by the SVC connection. A function of transmitting information to other converters, a function of receiving transfer data from other converters and storing correspondence information between the identification number of the converter and the destination IP address established by the SVC connection, and a packet received at the own device A function of checking the destination IP address for the data and transferring the incoming packet data to the other converter when the destination IP address is the SVC connection established by the other converter with reference to the correspondence information; When receiving the transfer of the incoming packet data from the converter, the destination IP address is set to the end node below the data link layer. Performs protocol conversion to address different networks data communication system characterized by comprising a function for sending to the appropriate end node address. Means for storing the correspondence between the SVC number and the destination IP address when the SVC connection is established by the own device;
Means for transmitting correspondence information between the identification number of the own device and the destination IP address established by the SVC connection to another converter when the SVC connection is established by the own device;
Means for receiving transfer data from another converter and storing correspondence information between the identification number of the converter and the destination IP address established by the SVC connection;
The destination IP address of the packet that has arrived at its own device is checked, and if the destination IP address is that the SVC connection has been established by another converter with reference to the correspondence information, the incoming packet is transferred to the other converter Comprising a means.

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