JP3390384B2 - Connection setting method and method in TCP / IP - Google Patents

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 devices having a predetermined protocol on a network. The present invention relates to a connection setting method and method in TCP / IP.

[0002]

2. Description of the Related Art TCP / IP is one of the conventional technologies of this type.
Protocol and X. A system using a protocol conversion device that realizes an interface with 25 protocols has been constructed. The X. 25 packets are H
It is transferred in a DLC frame, and this frame holds functions for obtaining reliability such as flow control and retransmission control. X. over 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, the connection is set before starting data transfer.

Further, the DTE address (DTE: Data Terminal Equipm) of the data terminal device is also used.
ent, data terminal device) as a system having a management means for selecting, for example, this system is a plurality of X2
5 terminals, a first relay device that connects a plurality of X25 terminals, a plurality of X25 servers, a second relay device that includes a plurality of line units that connect a plurality of X25 servers, and a first relay device, An IP network connecting to the second relay device,
The representative line unit representing the plurality of line units of the second relay device has a management means for managing the DTE address connected to the plurality of X25 servers for its own IP address.

As another conventional technique, PHS (Pe
rsonal System Interconnec
Japanese Patent Application Laid-Open No. 10-229416, in which the TCP / IP protocol is used for the TCP / IP protocol. In Japanese Patent Laid-Open No. 10-229416, the PHS on the transmission side and
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 transmitter, and the access point and the server are connected by the Internet. It is described that the communication between the access point and the server uses the TCP / IP protocol. When the PHS communicates with the server, the PHS is supposed to transmit the IP address of the access point as a method of connecting the access point and the server.

[0005]

However, in the above conventional technique, since TCP is connection type,
Set the IP address in the protocol conversion device connected to the source and destination devices, or make sure that the source terminal knows the IP address of the protocol conversion device in addition to the destination terminal address. There is a problem that you must stay.

Further, in the system provided with the management means for selecting the DTE address of the data terminal device, the X. 25 is connected to an X25 line section other than the representative line section, X.25. In order to set up a TCP connection for passing 25 packets, the request is made by adding the IP address of the representative line unit to the protocol conversion device of the other party, and a path is set once, but the representative line unit is connected to the X25 line unit. There is no DTE address of the X25 server that was set, so it is required to reset after releasing the path. In this case, since the other party is unknown, the TCP connection is released, reset, and X. This results in 25 retransmissions, which causes a problem that the delay time in the network significantly increases.

Further, Japanese Patent Laid-Open No. 10-22 using PHS
The 9416 publication also has the same problem as the above protocol conversion device.

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

Further, the terminal on the transmitting side can receive IP from anywhere.
It is to be able to communicate without being aware of the protocol.

Further, even if the apparatus is connected to a line section other than the representative line section of the transmission destination relay apparatus, the setting of the TCP connection is not repeated.

[0011]

In order to achieve the above object, the connection setting method in TCP / IP of the present invention is a first method for connecting a plurality of terminals to the plurality of terminals.
Relay device, a plurality of servers, a second relay device including a plurality of line units that connect the plurality of servers, and an IP network that connects the first relay device and the second relay device. A method for setting up a connection in TCP / IP using, wherein when the first relay device receives a call setup request from the terminal, the second relay device uses the UDP protocol to send the second call.
Requesting that the relay device of the server select the line part of the server that the relay device accommodates, and the second relay device selects the line part and assigns the IP address assigned to the line part. Returning to the first relay device using the UDP protocol, and encapsulating the call setup request received from the terminal with the IP address received by the first relay device as an IP packet, And a step of transmitting to the IP network.

Further, in the second relay device, by providing a representative line portion representing the line portions of the plurality of servers, the representative line portion selects the line portion of the server from the first relay device. Is selected, the IP address of the line section is selected.

Further, the second relay device is notified to the representative line section when detecting a change in connection with the server.

Further, the connection setting method in TCP / IP of 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. For connecting the second relay device, the first relay device, and the second relay device
In a connection setting method in TCP / IP including a network, the first relay device uses the UDP protocol to select a line part of the server accommodated by the relay device with respect to the second relay device. Requesting means for requesting the request, and the second relay device selecting a line section by the requesting means and returning the IP address assigned to the line section to the first relay device using the UDP protocol. And a transmission unit for encapsulating the call setup request from the terminal into an IP packet and transmitting the IP packet to the IP network, with the IP address received by the first relay device as the destination. I am trying.

Further, the second relay device is provided with a representative line section for selecting the IP address of the line section by the request means.

Further, the representative line unit stores in the storage unit a first conversion table containing the identification number of the server and the IP address of the line unit including itself corresponding to each identification number. It has a feature.

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 the storage unit of its own device, and from the terminal to the server. The second conversion table is searched and the IP address of the representative line unit is selected at the time of a call setup request to the.

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

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION 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 is X25.
It is composed of a terminal 1, access devices 2 and 3 (relay devices) that perform protocol encapsulation and routing, 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 has a DTE.
The address is assigned.

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

The representative line unit 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 joined by the communication function of IP forwarding. Further, the representative line unit 33 is assigned to each X25 line unit 34.
A 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 for new installation or expansion of the system.

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

The DTE-IP conversion table (not shown) is in a storage unit (not shown) in the conversion unit 24, and corresponds to the IP address assigned to the representative line unit 33, each of the X25 server groups 4 is associated with the IP address. The DTE address of the X25 server 41 is stored. Therefore, each of the other X25 server groups 4 connected to the other access device 3 is associated with 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 preset for new installation, expansion, etc. of the system.

Next, the operation of the present embodiment will be described with reference to FIGS. Referring to FIG. 1, X2
5 It is assumed that the terminal 1 communicates with the X25 server 41-1. The X25 terminal 1 starts with ITU Recommendation X. X.25. CR packet 11 which is 25 protocol
Edit (call request) and enter X. 25 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, the CR packet 1
Request message 1 to read the destination DTE address of 1 and request conversion of the destination DTE address into an IP address
In step 01, it is passed to the conversion unit 24 (sequence S2). Upon receiving the request message 101, the conversion unit 24 receives the DTE-I
IP of the representative line unit 33 assigned to the representative line unit 33 of the access device 3 stored in the P conversion table
The address is searched using the destination DTE address as a key, and the IP address obtained by the search is sent to the X25 line unit 22 in the response message 102 (sequences S3 and S4). Upon receiving the response message 102, the X25 line unit 22 transfers the transmission message 103 by adding the destination DTE address and IP address of the CR packet 11 to the router unit 26 (sequence S5). Upon receiving the incoming message, the router unit 26 receives the UDP (User Datagram).
Edit the IP packet specified by Protocol). That is, the router unit 26 edits the UDP inquiry message 201 and sends it to the IP network 5. At this time, the destination DTE address and 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
The router unit 31 of the above performs the basic IP routing processing and sends the UDP inquiry message 201 to the representative line unit 3
Forwarding to 3 (sequence S6). That is, the UDP inquiry message 201 is sent to the representative line unit 3
Pass it to 3 as it is. The representative line unit 33 receives the UD
X25 is obtained by searching the line search table using the destination DTE address in the P inquiry message 201 as a key.
X25 line unit 34-1 accommodating the line of the server 41-1
The IP address assigned to is obtained (sequence S7). The representative line unit 33 is the required line unit 3
4-1 the IP address of UDP response message 203
It is set to (IP packet) and transmitted to the access device 2 (sequence S8).

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

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

The router unit 26 of the access device 2 uses the TCP
When the connection response message 302 is received, the TCP connection 50 is sent between the router unit 26 and the line unit 34-1.
Recognizing that 0 has been established, X is received message 104.
25 to the line unit 22 (sequence S11). The X25 line unit 22 encapsulates the CR packet 11 into an IP packet and sends it to the path of the TCP connection 500 (addressed 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 route of the TCP connection 500, and the line unit 34-
Removed from capsule at 1. The line unit 34-1 is C
The line is determined from the DTE address in the R packet, and the CR packet is converted into the CN packet 13 (incoming call) and transmitted to the X25 server 41-1 (sequence S).
13).

Upon receiving the CN packet 13, the X25 server 41-1 edits the CA packet 15 (incoming call acceptance),
It is transmitted to the X25 terminal 1 (sequence S13).

Then, the line unit 34-1 of the access device 3 which has received the CA packet 15 encapsulates the CA packet 15 in an IP packet, and the TCP connection 500
Is transmitted along the route (to the IP address of the router unit 26).

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

The data exchange after the path is established between the X25 terminal 1 and the X25 server 41-1 is performed by the router section 26.
X. Communication in the IP network 5 is performed by encapsulating the 25 protocol packets into IP packets. On the other hand, when the access device 3 converts the received IP packet from encapsulation to X.264. Communication is performed with the X25 server 41-1 by removing the 25 protocol packet. That is, the X25 terminal 1 and the X25 server 41-1 are the X.
It means that they are communicating with each other using the 25 protocol.

As described above, the IP assigned to the X25 line unit 34 in the representative line unit 33 of the access device 3
The address is notified to the access device 2, and the notified I
Access device 2 and X2 by using P address
Since the path is set with the 5 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. Communication can be performed without resetting the TCP connection to the unit 34-1. 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 causes the X25 line unit 34-1 to the X25 line unit 34-n of the access device 3.
Suppose you are connected to. Then, the access device 3 displays 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 detection method of the access device 3 in this case is as follows.
It is customary for a person who performs maintenance to attend the system change, and at this time, the change value is input from the panel of the access device (not shown).

Further, as a method of detecting the access device 3, there is a method of automatically detecting a connection change of the X25 server.
In this case, the access device 3 controls the DTE under the line unit 34 (including the representative line unit 33) at regular intervals by the 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.

By the above processing, even if the X25 server 41 is moved under the control of another line unit 34 of the access device 3, it is possible to store the IP address of the X25 line unit 34 in the line search table and select the representative. X25 in the representative line unit 33 of the access device 3 that accommodates the X25 server group 4
25, after the call setting request packet transmitted by the terminal 1 arrives, it is possible to perform communication by performing processing such as round robin without resetting the TCP connection from the representative line unit 33 to the line unit 34-1. .

As described above, the X. 25 servers and X.25. Even if the 25 terminals are relayed by the IP network, the X. 25
Terminal and X. The 25 server does not need to be aware of the IP protocol (equipment of hardware and software).
It is possible to communicate using a packet defined by the 25 protocol.

Since the path is set by the UDP protocol between the relay devices, the X. The 25 terminals are the destination X.25. It is sufficient to know the DTE address of the 25 server, and X.25 can be used from anywhere without being aware of the IP protocol. 25 servers can be accessed.

Next, in the description of the first embodiment,
X. Although the description has been made by using the 25 communication protocol, it 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 section 71 for selecting a route of an IP packet which is IP-forwarded from the IP network 5, and a line section 7 for accommodating a server group line.
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 line of the server group 8. Router section 71, representative line section 7
3 and the line unit 74 are joined by the communication function of IP forwarding. Further, the representative line unit 73 has a line search table storing the IP address assigned to each line unit 74 and the telephone number of the server 81 housed in the line unit 74 in a storage unit (not shown). There is.
The line search table is set in advance for new installation or expansion of the system.

The access device 6 translates the IP address assigned to the line unit 62 accommodating the telephone set 9 and the telephone number of the other party when the call setup request is made from the telephone set 9 and the representative line unit 71 of the access unit 7. It is composed of a conversion unit 64 having a function (telephone number-IP conversion table) and a router unit 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 in association with the P address. Therefore, each server of the other 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. The telephone number of 81 is also stored. The telephone number-IP conversion table is set in advance when the system is newly installed or added.

In the description of the operation, when compared with the operation of the first embodiment, the UDP between the access devices 6 and 7 (between the router parts) is different only in that the protocol by the telephone line is different.
The operation for performing the communication (the voice communication by VOIP in the second embodiment) by setting the path by the TCP connection and then setting the path between the router unit 66 and the line unit 74 by the TCP connection is the same. Is omitted.

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

In the first and second embodiments described above, the access device 2 (or the access device 6) is the access device 2 (or the access device 6) which is a system configured in order to make the transmission side and the reception side easy to understand. 3 (or the access device 7) may be incorporated into the access device 3 (or the access device 7), respectively.

[0052]

As described above, according to the present invention, the path is set by the UDP protocol between the relay devices. Therefore, even if the devices having the same communication protocol are relayed by the IP network, the device for transmitting and receiving is There is an effect that communication can be performed using the communication protocol of the device itself without being aware of the IP protocol (equipment of hardware and software).

Further, according to the present invention, since the device address of the communication destination and the IP address used in the IP network are associated with each other by the conversion unit, the source device knows the line number of the destination device. The advantage is that the destination device can be accessed from anywhere without being aware of the IP protocol.

Further, according to the present invention, at the time of a transmission request from the transmission source, the IP address assigned to each line unit is notified to the representative line unit of the transmission destination relay device, and the notification is made. Since the path is set between the relay device of the transmission source and the line part of the transmission destination by using the IP address, the position of the incoming line is changed by the representative selection (the line other than the representative line part is selected). There is an effect that it is possible to reduce the network delay time due to the reconnection of the TCP connection due to the change of the path setting to the department.

Further, according to the present invention, since the path is set between the relay devices by the UDP protocol, as compared with the case where the terminal on the transmitting side secures it as an inquiry-only connection which needs to be aware of the TCP / IP protocol, Even in a network having a large number of terminals and servers such as a large-scale network, it is possible to avoid wasteful use of the TCP buffer port and the communication buffer holding time, which is a network resource.

Further, according to the present invention, after the path of the protocol used between the transmission source and the transmission destination is established by the UDP protocol, the data transmission / reception is performed between the transmission source and the transmission destination by the TCP protocol. There is an effect that it is possible to save network resources and obtain communication reliability by flow control and retransmission control that the TCP protocol has when transmitting and receiving data.

[Brief description of 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 x 25 terminal 2,3,6,7 access device 4 X25 server group 5 IP network 8 servers 9 telephones 22,34 X25 line part 24 Converter 26, 31, 66, 71 Router 33,73 Representative line section 41 X25 server 62,74 Line section 81 servers 100 circuit switching

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04L 12/56 H04L 12/46 H04L 12/66

Claims (8)

(57) [Claims] 1. A plurality of terminals, a first relay device that connects the plurality of terminals, a plurality of servers, and a second relay device that includes a plurality of line units that connect the plurality of servers, A connection setting method in TCP / IP using an IP network connecting a first relay device and the second relay device, wherein the first relay device receives a call setting request from the terminal, Requesting the second relay apparatus to select a line section of the server accommodated by the relay apparatus using the UDP protocol; and the second relay apparatus selecting the line section, UDP the IP address assigned to the department
Replying to the first relay device using a protocol, encapsulating the call setup request received from the terminal with the IP address received by the first relay device as an IP packet, And a step of transmitting to an IP network. 2. In the second relay device, by providing a representative line portion representing the line portions of the plurality of servers, the representative line portion selects the line portion of the server from the first relay device. IP of the line when there is a request for
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 connection with the server, it notifies 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 including a relay device and an IP network for connecting the second relay device, the first relay device uses a UDP protocol to the second relay device. , Requesting means for requesting selection of a line part of the server accommodated by the relay device, and the second relay device selecting the line part by the requesting means, and assigning an IP address assigned to the line part to U
Reply means for replying to the first relay device using a DP protocol, and the IP received by the reply means for the first relay device
IP address for call setup request from the terminal
A connection setting method in TCP / IP, comprising a transmission means for encapsulating the packet and transmitting it to the IP network. 5. The connection setting method in TCP / IP according to claim 4, wherein the second relay device comprises a representative line section for selecting the IP address of the line section by the requesting means. 6. The requesting means is provided for the second relay device.
Equipped with a representative line section for selecting the IP address of the line section
For example, the first relay device, a second conversion table containing the IP address of the representative line portion corresponding to the identification number of the destination has the storage unit of the own device, the call from the terminal to the server 5. The connection setting method in TCP / IP according to claim 4, further comprising means for searching the second conversion table and selecting an IP address of the representative line portion when a setting request is made. 7. In the second relay device, 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 each identification number. 7. The connection setting method in TCP / IP according to claim 5 or 6 , characterized in that it has means for storing it in the section. 8. The second relay device, upon detecting a change in connection with the server, notifies the representative line unit of the change and the first line
The connection setting method in TCP / IP according to claim 7, characterized in that it has rewriting means for rewriting the conversion table.