JP2001136202A - Method and system for setting connection in tcp/ip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow each device to mutually perform communication with a communication protocol between devices without being aware of an IP protocol even though relay is performed with an IP network (the Internet) between the devices having communication protocols other than a TCP/IP protocol. SOLUTION: An access device 2 requests an access device 3 to select the line of an X25 server group 4 housed by the device 3 by using a UDP in advance in the case of connecting the X25 server group 4 and an X25 terminal 1 by relaying an IP network 5. The device 3 selects the line (line part 34) in a representative line part 33 and returns an IP address attached to the part 34 to the device 2 by using the UDP. The device 2 uses the received IP address, encapsulates a call setting request packet received from the terminal 1 in a TCP and returns the call setting request packet to the network 5. Then, a path is set between the device 2 and the part 34 of the device 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection setting method and system in TCP / IP, and more particularly, to setting a path (connection) between relay devices for relaying a device having a predetermined protocol on a network. The present invention relates to a connection setting method and system in TCP / IP.

[0002]

2. Description of the Related Art As a prior art of this kind, TCP / IP
Protocol and X. A system using a protocol conversion device that realizes an interface with 25 protocols has been constructed. X. 25 packets are H
It is transferred as a DLC frame, and this frame has functions for obtaining reliability such as flow control and retransmission control. X. on the IP network When transmitting 25 packets, TCP having a function for obtaining reliability equivalent to HDLC is used as a substitute for the HDLC frame. Since TCP is a connection type, a connection is set before starting data transfer.

[0003] Further, a DTE address (DTE: Data Terminal Equipment) of a data terminal device is used.
ent, data terminal device), for example, this system includes a plurality of X2
5 terminals, a first relay device connecting a plurality of X25 terminals, a plurality of X25 servers, a second relay device including a plurality of line units connecting the plurality of X25 servers, and a first relay device. An IP network for connecting to the second relay device;
A representative line unit representing a plurality of line units of the second relay device has a management unit for managing DTE addresses connected to a plurality of X25 servers for its own IP address.

Another conventional technique is PHS (Pe).
rsonal System Interconnection
Japanese Patent Application Laid-Open No. H10-229416 which uses a TCP / IP protocol in the TCP / IP protocol. Japanese Patent Application Laid-Open No. Hei 10-229416 describes a PHS on the transmitting side,
There is an access point (computer) and a server on the receiving side. The PHS and the access point are connected by radio, a base station, a PHS network, and a transmitting device, and the access point and the server are connected by the Internet. And that the communication between the access point and the server uses the TCP / IP protocol. As a method for connecting the access point and the server when the PHS communicates with the server, the PHS transmits the IP address of the access point.

[0005]

However, in the above-mentioned conventional technology, since TCP is connection-type,
An IP address is set in the protocol converter connected to the source and destination devices, or the source terminal knows the IP address of the protocol converter in addition to the address of the destination terminal. There is a problem that you must put it.

[0006] In a system provided with management means for selecting a DTE address of a data terminal device, the X.264 standard is used. 25 is connected to another X25 line section other than the representative line section, In order to set up a TCP connection for passing 25 packets, a request is made by adding the IP address of the representative line unit to the destination protocol converter, and a path is set at one end, but the X25 line unit is connected to the representative line unit. Since there is no DTE address of the specified X25 server, it is required to reset the path after releasing the path. In this case, since the other party is not known, the release and reset of the TCP connection and the X.50 connection are performed. 25 retransmissions, causing a problem that the delay time in the network is greatly increased.

Further, Japanese Patent Application Laid-Open No. H10-22 using PHS
No. 9416 also has the same problem as the above-mentioned protocol converter.

In view of the above problems, an object of the present invention is to provide a T
Even if devices having communication protocols other than the CP / IP protocol are relayed over an IP network (Internet), the devices can communicate with each other using the communication protocol between the devices without being aware of the IP protocol.

[0009] In addition, the terminal on the transmitting side can receive an IP from anywhere.
The ability to communicate without being aware of the protocol.

[0010] Another object of the present invention is to prevent the setting of a TCP connection from being repeated even when a device is connected to a line unit other than the representative line unit of a relay device of a transmission destination.

[0011]

In order to achieve the above object, a connection setting method in TCP / IP according to the present invention comprises a plurality of terminals and a first terminal for connecting the plurality of terminals.
A relay device, a plurality of servers, a second relay device including a plurality of line units connecting the plurality of servers, and an IP network connecting the first relay device and the second relay device. A connection setting method in TCP / IP using the first relay device, when the first relay device receives a call setting request from the terminal, the second relay device uses a UDP protocol to transmit the call setting request.
Requesting the relay device to select a line unit of the server accommodated by the relay device, and the second relay device selects a line unit and assigns an IP address assigned to the line unit to the server. Replying to the first relay device using a UDP protocol, encapsulating the call setting request received from the terminal to the IP address received by the first relay device into an IP packet, Transmitting to the IP network.

Further, in the second relay device, by providing a representative line unit representing the line units of the plurality of servers, the representative line unit can select the line unit of the server from the first relay device. Is selected when the request is issued.

Further, the second relay apparatus notifies the representative line unit when detecting a change in connection with the server.

Further, the connection setting method in TCP / IP according to the present invention comprises a terminal, a first relay device connected to the terminal, a plurality of servers, and a plurality of line units connecting the plurality of servers. A second relay device, and an IP connecting the first relay device and the second relay device.
In a connection setting method in TCP / IP having a network, the first relay device selects a line unit of the server accommodated in the relay device with respect to the second relay device using a UDP protocol. And the second relay device selects a line unit by the request unit, and returns an IP address assigned to the line unit to the first relay device using a UDP protocol. Replies, and transmission means for encapsulating a call setting request from the terminal into an IP packet with the IP address received by the first relay device received by the reply means as a destination, and transmitting the encapsulated request to the IP network. And

Further, the second relay device is characterized by comprising a representative line unit for selecting an IP address of the line unit by the request unit.

Further, the representative line unit stores a first conversion table including an identification number of the server and an IP address of a line unit including itself corresponding to the identification number in a storage unit. Features.

Further, the first relay device has a second conversion table including the IP address of the representative line unit corresponding to the identification number of the transmission destination in its storage unit, When a call setting request is made, the second conversion table is searched to select the IP address of the representative line unit.

Further, the second relay device is characterized in that upon detecting a change in the connection with the server, it notifies the representative line unit and rewrites the conversion table.

[0019]

Next, a first embodiment of the present invention will be described with reference to the drawings. Referring to FIG.
The system according to the first embodiment of the present invention has an X25
It comprises a terminal 1, access devices 2 and 3 (relay devices) for encapsulating and routing a protocol, an X25 server group 4, and an IP network 5.

The X25 server group 4 is composed of a plurality of X25 servers 41, and each X25 server 41
Address is assigned.

The access device 3 includes a router unit 31 for selecting a route of an IP packet forwarded from the IP network 5, an X25 line unit 34 for accommodating a plurality of DTE addresses (identification numbers) of X25 server groups, and an X25 line unit. A representative line unit 33 for managing an IP address assigned to the X25 line unit 34 corresponding to a plurality of DTE addresses of the server group 4.

The representative line section 33 can also accommodate the line of the X25 server group 4. The router unit 31, the representative line unit 33, and the X25 line unit 34 are connected by a communication function of IP forwarding. Further, the representative line unit 33 is provided with the I assigned to each X25 line unit 34.
The storage unit (not shown) has a line search table storing the P address and the DTE address of the X25 server 41 accommodated in the X25 line unit 34. The line search table is set in advance when a system is newly installed or added.

The access device 2 has an X25 line unit 22 accommodating the X25 terminal 1, a destination DTE address of a call setting request packet from the X25 terminal 1, and an IP address assigned to the representative line unit 31 of the access device 3. Conversion unit 24 having a conversion function (DTE-IP conversion table)
And a router unit 26 for connecting to the IP network 5.

A DTE-IP conversion table (not shown) is stored in a storage unit (not shown) in the conversion unit 24, and corresponds to each IP address assigned to the representative line unit 33. The DTE address of the X25 server 41 is stored. Accordingly, each of the other X25 server groups 4 connected to the other access device 3 corresponds to the IP address of the representative line unit 33 of the other access device 3 (not shown) connected to the IP network 5. The DTE address of the X25 server 41 is also stored. In addition, DTE
-The IP conversion table is set in advance when a system is newly installed or added.

Next, the operation of this embodiment will be described with reference to FIGS. Referring to FIG. 1, X2
It is assumed that the five terminals 1 communicate with the X25 server 41-1. First, the X25 terminal 1 is based on ITU Recommendation X.31. X.25 specified in X.25. CR protocol 11 which is 25 protocol
(Call request), and edit X. 25 is transmitted to the server 41-1 (sequence S1 in FIG. 2).

Then, the X25 line unit 2 of the access device 2
2 receives the CR packet 11 and receives the CR packet 1
Request message 1 for reading the destination DTE address of the first DTE 1 and requesting conversion of the destination DTE address to the IP address
At 01, it is passed to the conversion unit 24 (sequence S2). Upon receiving the request message 101, the conversion unit 24 converts the DTE-I
The IP address of the representative line unit 33 assigned to the representative line unit 33 of the access device 3 stored in the P conversion table
An address is searched using the destination DTE address as a key, and the IP address obtained by the search is passed to the X25 line unit 22 in the response message 102 (sequences S3 and S4). Upon receiving the response message 102, the X25 line section 22 puts the destination DTE address and the IP address of the CR packet 11 on the transmission message 103 and passes them to the router section 26 (sequence S5). Upon receiving the incoming message, the router 26 receives a UDP (User Datagram) message.
Protocol) is edited. That is, the router unit 26 edits the UDP inquiry message 201 and transmits it to the IP network 5. At this time, the destination DTE address and the IP address of the passed CR packet 11 are set in the UDP inquiry message 201 (sequence S6).

Access device 3 received via IP network 5
Router unit 31 performs basic IP routing processing and sends UDP inquiry message 201 to representative line unit 3.
3 (sequence S6). That is, the UDP inquiry message 201 is transmitted to the representative line unit 3
Hand it over to 3. The representative line unit 33 receives the received UD
By searching the line search table using the destination DTE address in the P inquiry message 201 as a key, X25
X25 line unit 34-1 accommodating the line of server 41-1
Is determined (sequence S7). The representative line unit 33 is the corresponding line unit 3
4-1 IP address in UDP response message 203
(IP packet) and transmit it to the access device 2 (sequence S8).

UDP response message 2 via IP network 5
The router unit 26 of the access device 2 that has received 03 receives and edits the TCP connection request message 301 from the received IP address and transmits it (sequence S9).

The line unit 3 of the access device 3 that has received the TCP connection request message 301 via the IP network 5
4 transmits a TCP connection response message 302 to the TCP connection request message 301 (sequence S10).

The router 26 of the access device 2
When the connection response message 302 is received, the TCP connection 50 is transmitted between the router 26 and the line 34-1.
0 is established, the received message 104
25 to the line section 22 (sequence S11). The X25 line unit 22 encapsulates the CR packet 11 into an IP packet and transmits it to the path of the TCP connection 500 (to the IP address of the X25 line unit 34-1) (sequence S12).

The CR packet 11 encapsulated in the IP packet arrives at the line unit 34-1 of the access device 3 through the path of the TCP connection 500, and
Removed from the capsule at 1. The line unit 34-1 has C
The line is determined from the DTE address in the R packet, and the CR packet is converted into a CN packet 13 (incoming call) and transmitted to the X25 server 41-1 (sequence S).
13).

The X25 server 41-1 that has received the CN packet 13 edits the CA packet 15 (accepts a call),
It transmits to X25 terminal 1 (sequence S13).

Then, the line unit 34-1 of the access device 3 that has received the CA packet 15 encapsulates the CA packet 15 in an IP packet, and
(To the IP address of the router unit 26).

The X25 line unit 22 of the access device 2 that has received the CA packet 15 encapsulated in the IP packet via the IP network 5 removes the CA packet 15 from the capsule and converts it into a CC packet 17 (connection completed). hand,
Send to X25 terminal 1.

Data exchange after the path between the X25 terminal 1 and the X25 server 41-1 is established is performed by the router unit 26.
Is X. Communication on the IP network 5 is performed by encapsulating a packet of 25 protocol into an IP packet. On the other hand, the access device 3 converts the received IP packet from the encapsulated X. The communication with the X25 server 41-1 is performed by removing the packet of the 25 protocol. That is, the X25 terminal 1 and the X25 server 41-1 transmit the X.25 terminal.
It means that they are communicating with each other using 25 protocols.

As described above, the IP address allocated to the X25 line unit 34 is assigned to the representative line unit 33 of the access device 3.
The address is notified to the access device 2, and the notified I
By using the P address, the access device 2 and X2
Since the path setting is performed with the five-line unit 34, after the call setting request packet transmitted by the X25 terminal 1 arrives at the representative line unit 33 of the access device 3, the line is transmitted from the representative line unit 33. The communication can be performed without setting the TCP connection to the unit 34-1 again. That is, the delay time of the network due to the reconnection of the TCP connection can be reduced.

Next, the X25 server 41-1 connects the X25 line unit 34-1 to the X25 line unit 34-n of the access device 3.
Suppose you connect to Then, the access device 3 becomes X25
It detects that the line of the server 41-1 has been switched, and notifies the representative line unit. The representative line unit 33 changes the IP address of the X25 line unit 34-1 corresponding to the DTE address of the X25 server 41-1 registered in the line search table to the IP address of the X25 line unit 34-n.

The method of detecting the access device 3 in this case is as follows.
Usually, the system is changed by a person who performs maintenance, and a change value is input from a panel of an access device (not shown).

As a method of detecting the access device 3, there is a method of automatically detecting a change in the connection of the X25 server.
In this case, the access device 3 sets the DTE under the line unit 34 (including the representative line unit 33) at regular intervals by a timer.
The address is read, the line search table of the representative line unit 33 is searched, and if there is a change, the IP address of the line unit 34 corresponding to the DTE address is rewritten.

According to the above processing, even if the X25 server 41 moves to a position under another line unit 34 of the access device 3, only the IP address of the X25 line unit 34 is stored in the line search table, and the representative selection is performed. The representative line unit 33 of the access device 3 that accommodates the X25 server group 4
After the call setting request packet transmitted by the terminal 25 arrives, it is possible to perform communication without performing the setting of the TCP connection from the representative line unit 33 to the line unit 34-1 again by processing such as round robin. .

As described above, X. Server and X.25. Even if the relay between the 25 terminals is performed via the IP network, the X.25. 25
Terminal and X. The X.25 server does not need to be aware of the IP protocol (equipment of hardware and software).
Communication can be performed using a packet defined by 25 protocols.

Further, since the path setting between the relay apparatuses is performed by the UDP protocol, the X.X. 25 terminal is the destination X.25. It is only necessary to know the DTE address of the X.25 server. 25 servers can be accessed.

Next, in the description of the first embodiment,
X. Although the description has been made using the 25 communication protocols, the present invention can be applied by replacing with another communication protocol.
Therefore, VOIP (Voice) via the IP network 11
A second embodiment of the present invention in Over Internet Protocol will be described with reference to the drawings. Referring to FIG. 3, the system according to the second embodiment of the present invention includes a telephone 9 and access devices 6 and 7.
, A server group 8, an IP network 5, and a circuit switch 100.

The server group 8 is composed of a plurality of servers 81, and each server 81 is assigned a telephone number.

The access device 7 includes a router 71 for selecting a route of an IP packet to be forwarded from the IP network 5 and a line 7 for accommodating a line of a server group.
4 and a representative line unit 73 that manages the telephone number of the server group 8 and the IP address assigned to the line unit 34.

The representative line section 73 can also accommodate the lines of the server group 8. Router 71, representative line 7
3 and the line section 74 are connected by a communication function of IP forwarding. Further, the representative line unit 73 has a line search table storing an IP address assigned to each line unit 74 and a telephone number of the server 81 housed in the line unit 74 in a storage unit (not shown). I have.
The line search table is set in advance when a system is newly installed or added.

The access device 6 converts a line unit 62 accommodating the telephone 9, a telephone number of a partner at the time of a call setting request from the telephone 9, and an IP address assigned to the representative line unit 71 of the access device 7. It comprises a conversion section 64 having a function (telephone number-IP conversion table) and a router section 66 for connecting to the IP network 5.

The telephone number-IP conversion table (not shown) is stored in a storage unit (not shown) in the conversion unit 64 and is assigned to the representative line unit 73 of the access device 7.
The telephone number of each server 81 of the server group 8 is stored corresponding to the P address. Accordingly, each server of another server group 8 connected to the other access device 7 corresponding to the IP address of the representative line unit 73 of the other access device 7 not shown connected to the IP network 5 81 telephone numbers are also stored. The telephone number-IP conversion table is set in advance when a system is newly installed or added.

The operation is different from the operation of the first embodiment only in the protocol of the telephone line, except for the UDP between the access devices 6 and 7 (between the routers).
The operation of setting a path by the router and then setting a path between the router unit 66 and the line unit 74 by the TCP connection and performing communication (in the second embodiment, voice communication by VOIP) is the same operation. Is omitted.

Therefore, it can be said that in the VOIP via the IP network 5, the representative line unit 73 can select an input path of the circuit switching 100.

In the first and second embodiments, the system is configured so that the transmitting side and the receiving side can be easily understood, and the access device 2 (or the access device 6) is connected to the access device 2 (or the access device 6). The function of the access device 3 (or the access device 7) and the function of the access device 2 (or the access device 6) may be incorporated in the access device 3 (or the access device 7).

[0052]

As described above, according to the present invention, since the path setting is performed between the relay apparatuses according to the UDP protocol, even if the apparatuses having the same communication protocol are relayed by the IP network, the apparatus that performs transmission and reception is not required. In addition, there is an effect that communication can be performed using the communication protocol of the apparatus itself without being aware of the IP protocol (equipment of hardware and software).

In the present invention, since the address of the communication destination is associated with the IP address used in the IP network by the conversion unit, the transmission source device determines the line number of the transmission destination device. Thus, there is an effect that the destination device can be accessed from any location without being aware of the IP protocol.

Further, according to the present invention, at the time of a transmission request from a transmission source, the IP address assigned to each line unit to the representative line unit of the transmission destination relay device is notified to the transmission source relay device, and the notification is made. Since the path is set between the transmission source relay device and the transmission destination line unit by using the IP address, the position of the incoming line is changed by the representative selection (the line other than the representative line unit). There is an effect that the network delay time can be reduced by reconnecting the TCP connection accompanying the change of the setting of the path to the section.

Further, in the present invention, since the path setting is performed between the relay devices using the UDP protocol, the transmission side terminal is required to be aware of the TCP / IP protocol as a dedicated connection for inquiries. Even in a network having a large number of terminals and a large number of servers such as a large-scale network, there is an effect that the holding time of the communication buffer and the TCP port, which are network resources, can be avoided from being wastefully used.

Further, according to the present invention, when a path of a protocol used between a transmission source and a transmission destination is established by a UDP protocol, and data is transmitted and received between the transmission source and the transmission destination by a TCP protocol, the combination of It is possible to save network resources, and to obtain reliability of communication by flow control and retransmission control of the TCP protocol at the time of data transmission / reception.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system according to a first embodiment of the present invention.

FIG. 2 is a sequence diagram showing an operation when establishing a communication path according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a system according to a second embodiment of the present invention.

[Explanation of symbols]

 1 X25 terminal 2, 3, 6, 7 access device 4 X25 server group 5 IP network 8 server group 9 Telephone 22, 34 X25 line unit 24 Conversion unit 26, 31, 66, 71 Router unit 33, 73 Representative line unit 41 X25 Server 62, 74 Line section 81 Server 100 Line switching

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (8)

[Claims] 1. A plurality of terminals, a first relay device connecting the plurality of terminals, a plurality of servers, and a second relay device including a plurality of line units connecting the plurality of servers,
A connection setting method in TCP / IP using an IP network connecting the first relay device and the second relay device, wherein the first relay device receives a call setting request from the terminal Requesting, using a UDP protocol, the second relay device to select a line unit of the server accommodated by the relay device, and the second relay device selects a line unit, Returning an IP address assigned to a line unit to the first relay device using a UDP protocol; and receiving the IP address received by the first relay device from the terminal as a destination. Encapsulating a call setting request into an IP packet and transmitting the request to the IP network. 2. In the second relay device, a representative line unit representing the line units of the plurality of servers is provided, so that the representative line unit selects a line unit of the server from the first relay device. Of the line section when there is a request of
2. The TC according to claim 1, wherein an address is selected.
Connection setting method in P / IP. 3. The connection setting method in TCP / IP according to claim 2, wherein when the second relay device detects a change in the connection with the server, the change is notified to the representative line unit. 4. A terminal, a first relay device connected to the terminal, a plurality of servers, a second relay device including a plurality of line units connecting the plurality of servers, and the first relay device. In a connection setting method in TCP / IP provided with a relay device and an IP network connecting the second relay device, the first relay device transmits the second relay device to the second relay device using a UDP protocol. Request means for requesting selection of a line unit of the server accommodated by the relay device, and the second relay device selects a line unit by the request means, and sets the IP address assigned to the line unit to U
Return means for returning to the first relay device using a DP protocol; and a call setting request from the terminal addressed to the IP address received by the first relay device by the return means in an IP packet. And transmission means for transmitting to the IP network.
Connection setting method in P. 5. The connection setting method according to claim 1, wherein the second relay device includes a representative line unit for selecting an IP address of the line unit by the request unit. 6. The server according to claim 1, wherein the representative line unit includes an identification number of the server and an IP address of a line unit including itself corresponding to each of the identification numbers.
6. The connection setting method in TCP / IP according to claim 5, wherein a first conversion table including an address is stored in a storage unit. 7. The first relay device includes a second conversion table including an IP address of the representative line unit corresponding to an identification number of a transmission destination in a storage unit of the first relay device. 7. The connection setting method in TCP / IP according to claim 5, wherein the second conversion table is searched when a call setting request is made, and the IP address of the representative line unit is selected. 8. The connection in TCP / IP according to claim 5, wherein the second relay device, upon detecting a change in connection with the server, notifies the representative line unit and rewrites the conversion table. Setting method.