JPH0774775A - Inter-lan connector - Google Patents

Abstract

PURPOSE:To execute redialing automatically without any loss when dialing to other LAN Is failed in the inter-LAN connector interconnecting different LANs via an ISDN line network. CONSTITUTION:When a packet addressed to other LAN is sent via an interface 21 to a dial means 23, the means 23 reads an ISDN number corresponding to an address of a destination LAN from a dial destination table 24 and sends it to an ISDN line network. The ISDN line network tries to connection to the number and when the opposite party does not reply, an interruption reason code representing the reason is sent to a caller side. A redial control means 26 uses an interruption reason code discrimination means 25 discriminates the interruption reason code from the ISDN line network to be a code expected for early recovery, the means 25 makes a request of radialing to the same opposite party to the dial means 23.

Description

Detailed Description of the Invention

[0001]

The present invention relates to ISDN between different local area networks (hereinafter referred to as LAN).
The present invention relates to a LAN-to-LAN connecting device connected via a line network.

[0002]

2. Description of the Related Art A LAN is used as a data communication network for performing data communication between terminal devices within a relatively small range such as within a company or within a limited area. However, in order to expand the network, a LAN-to-LAN connecting device has been conventionally proposed that enables data exchange between terminal devices of different LANs.

FIG. 9 shows a conventional router type LAN inter-connector 11 _{1 to} 11 ₃ among the LAN inter-connectors of this type.
Are respectively connected between different LANs 1, 2 and 3 and the ISDN line network 10, and LAN terminals 1a to 1c and 2a are connected.
2c and 3a to 3c, a network is configured to be capable of exchanging data. Each of the inter-LAN connecting devices 11 _{1 to} 11 ₃ is provided with a calling means 12 and a callee table 13 for making a call to a different LAN side via the ISDN line network 10.

Here, a unique network address representing the network itself is assigned in advance to each of the LANs _{1 to 3} , and the call destination table of the inter-LAN connecting device 11 ₁ contains the network addresses of the LANs 2 and 3. LA
N connecting unit 11 _2, and the 11 ₃ of ISDN numbers are stored are respectively correspondence, to the call destination table of the LAN-to-LAN connecting device 11 _2, the network address and the LAN connecting device 11 ₁ LAN1,3, The ISDN number of 11 ₃ is stored in association with the LAN connection device 11 ₃
In the call destination table, the network addresses of the LANs ₁ and _{2 and} the ISDN numbers of the inter-LAN connecting devices 11 ₁ and 11 ₂ are stored in association with each other.

Then, for example, from the terminal 1a of LAN1 to the inter-LAN connecting device 11 ₁ , the terminal 3c of LAN3 is connected.
When a packet transfer request is made with the address of the other party as the destination address, the inter-LAN connecting device 11 ₁ sends the ISDN line network 10 the ISDN of the inter-LAN connecting device 11 ₃ corresponding to the network address included in the destination address.
Call a number. As a result, the ISDN network 10 becomes L
Attempt to connect to the inter-AN connection device 11 ₃ .

At this time, if the LAN connection device 11 ₃ is not connected to any LAN, the LAN connection device 11 ₃ responds to this call and the LAN connection device 11 ₁ , A link between 11 ₃ is established, and LAN 1 and LAN 3 are connected. After that, the inter-LAN connecting device 11 ₃ re-relays the packet sent from the terminal 1 a to the terminal 3 c, which is sent by relaying the inter-LAN connecting device 11 ₁ , and sends the packet to the terminal 3 c, and this packet is received by the terminal 3 c. It

The connection between the LANs is LAN1,
The same is done between 2 or LAN 2, 3.
Data communication can be freely performed between terminals of different LANs.

If the LAN2 terminal issues a call request to the LAN1 while the LAN1 and the LAN3 are connected to each other via the LAN connecting devices 11 ₁ and 11 ₃ as described above, The ISDN line network 10 judges that the inter-LAN connecting device 11 ₁ is busy and notifies the inter-LAN connecting device 11 ₂ of the call failure.

[0009]

However, in the conventional LAN-to-LAN connecting device via the ISDN line network as described above, when the call is unsuccessful, the packet from the terminal is received again or the operator operates. However, there is a problem in that even if the reconnection cannot be attempted, and even if the other party is out of order and there is no possibility of connection, this wasteful reconnection is attempted.

When the call is unsuccessful, the ISDN network notifies the caller of the reason as a disconnection reason code. From this disconnection reason, it is possible to discriminate between a case where there is a possibility of recovery after a while, such as a busy situation, and a case where there is no prospect of recovery for the time being due to a failure.

According to the present invention, the disconnection reason code is actively used by the LAN-to-LAN connecting device itself, and when early recovery is expected, there is no need to wait for the packet to be retransmitted from the terminal or the operator's operation, and It is an object of the present invention to provide a LAN-to-LAN connecting device that enables efficient and quick communication by re-calling by the connecting device itself.

[0012]

In order to solve the above-mentioned problems, the inter-LAN connecting device of the present invention is connected between a local area network and an ISDN line network, and the ISD
A calling means for receiving data destined for another local area network connected through the N line network from the local area network and making a call to the other local area network for the ISDN line network; ,
In a LAN-to-LAN connecting device that enables data exchange between the other local area network responding to the call and the local area network of the calling side, the calling means connects the other local area network to the other local area network. A disconnection reason code determining means for receiving a disconnection reason code sent from the ISDN line network when the call is unsuccessful and determining whether or not the disconnection reason code can be expected to be recovered early by a re-call. When the disconnection reason code determining means determines that the disconnection reason code sent from the ISDN line network is a code that can be expected to be recovered early, the calling means again makes a call to another local area network. And a recalling control means for enabling the recalling.

[0013]

With this configuration, in the LAN-to-LAN connecting apparatus of the present invention, the disconnection reason code sent from the ISDN line network when a call to another local area network fails, such as busy. When it is determined that the code can be expected to be recovered early, the local area network is automatically re-called.

[0014]

[First Embodiment] A first embodiment of the present invention will be described below with reference to the drawings. For example, as shown in FIG.
₁ shows a configuration of router-type LAN-to-LAN connecting devices 20 _{1 to} 20 ₃ provided for each of the LANs _{1 to 3} in order to connect different LANs via the DN network 10.

Each of the LAN connecting devices 20 _{1 to} 20 ₃ includes
Interface (I / F) 2 for each LAN
1 and the ISDN line network 10 interface (I /
F) 22 is provided.

When the interface 21 receives a packet addressed to another LAN terminal from a LAN terminal, it issues a call request to the calling means 23 and sends the packet to the interface 22. In addition, this interface 21
Sends a packet from the interface 22 (that is, from another LAN side) to the LAN side.

The interface 22 sends the packet received from the interface 21 to the ISDN line network 10 when the other side responds to the call made by the calling means 23, and when this call fails, the disconnect reason code is sent. I
The disconnection reason code received from the SDN line network 10 is sent to the disconnection reason code determination means 25 described later. Also,
When the interface 22 receives a call from the ISDN line network 10, the interface 22 responds to the call and sends the packet sent from the call side to the interface 21.

When the calling means 23 receives the calling request from the interface 21 and the calling request from the calling control means 26 described later, the ISD corresponding to the network address of the destination received by the interface 21 from the LAN.
The number of the N line (ISDN number) is stored in the callee table 24.
Read from ISDN via interface 22
It is sent to the line network 10.

In the callee table 24, the network address of another LAN, the LAN and the ISDN line network 1
The ISDN numbers of the LAN-to-LAN connecting devices that are connected to 0 are stored in advance in one-to-one correspondence.

That is, the LAN-to-LAN connecting device 20 on the LAN 1 side
_As shown in FIG. 3, the call destination table 24 of _{No. 1} has LA
The ISDN number N2 of the inter-LAN connecting device 20 ₂ is associated with the network address B of N2, and the LAN3
LAN connection device 2 for network address C of
The ISDN number N3 of 0 ₃ is associated and stored.

Similarly, the LAN on the LAN2 side
In the callee table 24 of the inter-connector 20 ₂ , the LAN 1
LAN connection device 2 for network address A of
The ISDN number N1 of 0 ₁ is associated with the network address C of the LAN _{3 and the} inter-LAN connecting device 20 ₃
ISDN number N3 of is associated and stored,
Further, in the call destination table 24 of the LAN-to-LAN connecting device 20 ₃ on the LAN3 side, the ISDN number N1 of the LAN-to-LAN connecting device 20 ₁ is associated with the network address A of LAN1 and the network address B of LAN2 is associated. The ISDN number N2 of the LAN-to-LAN connecting device 20 ₂ is associated and stored.

The disconnection reason code judging means 25 uses the ISDN.
It is determined whether the disconnection reason code sent from the line network 10 is a code that can be expected to recover early.

That is, as one of the services, the ISDN line network 10 disconnects the line to the calling party and sends the reason for the disconnection to the calling side with a predetermined code. .

For example, when the other party normally responds to the call and communication is completed and a disconnection request is made from one of the line sides, a disconnection reason code [10] indicating normal disconnection is given.
When the calling line is already connected to another line, the disconnect reason code [1
1], and the terminal of the other party (in this case, L
When the inter-AN connection device) is out of order, the disconnect reason code [1B] indicating that the other terminal is out of order is transmitted.

The disconnection reason code judging means 25 stores in advance a disconnection reason code which can be expected to be recovered after a while, such as user busy, and an early recovery can be performed based on the disconnection reason code from the ISDN line network 10. It is determined whether it can be expected.

When the disconnection reason code judging means 25 judges that the disconnection reason code from the ISDN line network 10 is a code that can be expected to be recovered early, the re-calling control means 26 gives the calling means 23 a predetermined time. (Eg 10
(Seconds) later, a re-call request for calling the same party again is output a predetermined number of times. When the calling means 23 receives this re-call request, it makes a call to the same party again.

FIG. 4 shows the LAN connecting devices 20 ₁ to 20 2.
0 is a flowchart showing the _third processing procedure. The operation of the inter-LAN connecting device 20 ₁ when sending data from the terminal 1a of LAN1 to the terminal 3c of LAN3 will be described below based on this flowchart.

First, the LAN-to-LAN connecting device 20 receives a packet from the terminal 1a which is the transmission source to the terminal 3c which is the other end.
₁ is the ISD of the inter-LAN connecting device 20 ₃ corresponding to the destination network address included in this packet
The N number N3 is read and the ISDN line network 10 is called (S1 to 3).

The ISDN line network 10 receives a call to this ISDN number N3 and tries to connect to the line of this number. At this time, when the LAN-to-LAN connecting device 20 ₃ on the partner side responds (that is, when the call is successfully made), the line between N1 and N3 is connected, and the LAN-to-LAN connecting device 20 _{1 is} connected.
From the LAN connection device 20 ₃ to the L
The packet is sent from the inter-AN connection device 20 ₃ to the terminal 3c, and data is communicated between the terminals 1a and 3c.
The N-to-N connection devices 20 ₁ and 20 ₃ relay packets between terminals until the communication is completed (S4 to 6).

Also, in response to this connection attempt, there is no response from the LAN connection device 20 ₃ on the other side, and the disconnection reason code as a reason for disconnecting the line from the ISDN line network 10 when the call fails. When sent, LAN connecting device 20 ₁ determines whether or not the disconnect reason code is code that expected of early recovery (S7 and S8).

Here, for example, the LAN inter-connector 20 ₃ on the other side is already connected to the LAN inter-connector 20 ₂ , and the ISDN line network 10 sends the disconnect reason code indicating the user busy of code [11]. When being come, LAN connecting device 20 _1, the code determines that the code expected of early recovery, performed continuously recalling up to the number of times M that is determined every predetermined time (for example, every 10 seconds) (S9 ~
11).

During this period, the LAN connection device 20 on the other side
_When the communication between the LAN connection device 20 ₃ and the other LAN connection device 20 ₂ is completed and the LAN connection device 20 ₃ responds to the re-call, the process proceeds to the relay process of step S5. Further, even if the call is retried a predetermined number of times, the call is stopped when the other party does not respond.

Further, the disconnection reason code that is not expected to recover early, for example, the code [1B] indicating that the terminal is in failure is the ISD.
When the call is sent from the N line network 10, this re-call process is not performed.

The above operation is performed from the LAN2 side to the LAN.
Calls to the first side, calls from the LAN2 side to the LAN3 side, and vice versa are performed in exactly the same manner.

As described above, the LAN-to-LAN connecting device of this embodiment is ISDN when the call to the other LAN side fails.
When it is determined that the disconnection reason code sent from the line network is a code that is expected to be recovered early, the other party is automatically called again, so that efficient communication can be performed.

[0036]

Second Embodiment In the above-described embodiment, the present invention is applied to the inter-LAN connecting device provided for each LAN, but, for example, as shown in FIG.
Multiple LAN connection devices 30 _{21 to} 3
0 ₂₃ , 30 ₃₁ to 30 ₃₃ are connected to the ISDN line network 10, and the LAN 1 side is connected by one LAN connection 30 ₁₁ I
A network connected to the SDN line network 10 is also conceivable.

That is, in such a network, a call is made to the LAN side having a plurality of inter-LAN connecting devices, and when the call fails, a call is made by the next ISDN number, which is different. Efficient L by using route
Connection between AN is possible.

FIG. 6 shows an L which enables such a different route call.
The structure of the 2nd Example which applied this invention to the inter-AN connection apparatus is shown. In this figure, the same constituent elements as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In each call destination table 31 of the inter-LAN connecting devices 30 ₁₁ to 30 ₃₃ , the ISDN numbers of a plurality of LANs that can be connected to another LAN are stored in advance for the network addresses of the other LANs. Has been done.

For example, as shown in FIG. 7, in the call destination table of the LAN-to-LAN connecting device 30 ₁₁ , the LAN-to-LAN connecting devices 30 ₂₁ to 30 connected to the LAN 2 for the network address B of the LAN 2 are connected. ₂₃ ISDN numbers N2
1 to N23 are stored in advance, and for the network address C of LAN3, the LA connected to that LAN3
ISDN numbers N31 to N of N-to-N connecting devices 30 ₃₁ to 30 ₃₃
33 is stored in advance.

Similarly to this, the inter-LAN connecting device 3
In each call destination table of 0 ₂₁ to 30 ₂₃ , the LAN connection device 30 _{11 is} connected to the network address A of LAN 1.
The ISDN number N11 of the LAN connection device 30 ₃₁
To 30 ₃₃ ISDN number N31~N33 of are stored in advance. Furthermore, in each call destination table of the inter-LAN connecting devices 30 ₃₁ to 30 ₃₃ , for the network address A of LAN 1, the ISDN number N of the inter-LAN connecting device 30 ₁₁ is set.
11 is stored in advance, and the ISD of the inter-LAN connecting devices 30 ₂₁ to 30 ₂₃ is corresponding to the network address B of LAN 2.
N numbers N21 to N23 are stored in advance.

Further, the ISDN numbers read from the calling destination table by the calling means 23 are sequentially designated to the respective LAN-to-LAN connecting devices each time the calling fails, and a calling by a different route is requested. Different route call control means 32 is provided.

Whenever the disconnection reason code judging means 25 judges that the disconnection reason code when the calling by the calling means 23 fails is a code which can be expected to recover early, Used to make the call
For example, a flag of 1 is set in the flag area F (see FIG. 7) of the call destination table 31 corresponding to the SDN number, and when it is determined that the code cannot be expected to be recovered early, the flag of 0 is set. Then, when the different-route call control means 32 makes a call using all the ISDN numbers corresponding to the partner network and all of those calls are unsuccessful, the different-route call control means 32 is called. On the other hand, a different route call is made only by the ISDN number for which the flag of 1 is set, and a re-call is made to the LAN-to-LAN connecting device having the ISDN number for which early recovery is expected.

FIG. 8 shows a processing procedure of the LAN-to-LAN connecting device configured as described above. The call origination operation from the terminal 1a of LAN1 to the terminal 3c of LAN3 will be described below with reference to this flowchart.

Terminals 1a to 3c as in the above embodiment
When a packet addressed to the LAN-to-LAN connecting device 30 ₁₁ is requested to make a call, the LAN-to-LAN connecting device 30 ₁₁ determines that the LAN-to-LAN connecting device corresponding to the destination network address included in the packet. ISDN of 30 ₃₁ to 30 ₃₃
Initialize all the flags of the numbers N31 to N33 to 1 and then read the first ISDN number N31 to
The N line network 10 is called (S1-4).

The ISDN line network 10 receives a call to this ISDN number N31 and tries to connect to this number.

When the other party LAN connecting device 30 ₃₁ responds to this call (that is, when the call succeeds)
The line between N11 and N31 is connected to the LAN
During packet is sent from the connected device 30 ₁₁ to the LAN connecting unit 30 _31, the LAN connecting unit 30 ₃₁ of the terminal 3c navel packet is sent, the communication of the packet is performed between the terminals 1a, 3c, LAN connecting unit 30 ₁₁ and 30 ₃₁ relay packets between terminals until communication is completed (S5 to S5).
7).

In response to the connection attempt, there is no response from the LAN connection device 30 ₃₁ on the partner side, and the disconnection reason code is sent from the ISDN line network 10 when the call fails. The LAN-to-LAN connecting device 30 ₁₁ determines whether or not this disconnection reason code is a code that can be expected to recover early (S8-9).

Here, for example, when the other party's LAN connection device 30 ₃₁ is out of order and a disconnection reason code indicating that the terminal is out of order is sent from the ISDN line network 10, the LAN connection device 30 ₁₁ It is judged that this code is not expected to be recovered early, and ISDN of the callee table is judged.
The flag corresponding to the number N31 is set to 0 (S1
0).

When the other party's LAN connecting device 30 ₃₁ is already connected to the LAN connecting device 30 ₂₂ , for example, and the disconnect reason code indicating user busy is sent from the ISDN line network 10, the LAN connecting device 30 ₃₁ Connection device 30
₁₁ determines that this code is a code for which early recovery is expected, and leaves the flag corresponding to the ISDN number N31 of the callee table as 1.

When the call by the ISDN number N31 fails, the next ISDN number N32 is read out and the same processing as described above is performed. When the call by the last ISDN number N33 fails, the recurrence by the ISDN number of the flag 1 occurs. The call is repeated until M times (S11 to 13).

In the meantime, when one of the LAN-to-LAN connecting devices on the partner side responds to the re-call, the process shifts to the relay process of the process S5. In addition, even if the Mth call is recalled, the call is stopped when the other party does not respond.

Further, when the flags corresponding to all the ISDN numbers on the other side become 0, this re-call processing is stopped.

The above operation is performed from the LAN2 side to the LAN.
Calling to the 1 side, calling from the LAN 2 side to the LAN 3 side, and the like are performed in exactly the same manner.

In the LAN-to-LAN connecting device of this embodiment, a different route is used to make a call to the target LAN side to increase the connection probability, and furthermore, the reason for the call failure is judged to recover early. Since only the ones that have the potential are left as candidates for the next call route and the different route call is made again, there is an effect that it is not necessary to make a call by an unnecessary route.

[0056]

Other Embodiments In the above two embodiments, the router type LAN connecting device has been described, but the present invention can be applied not only to the router but also to the LAN connecting device such as a bridge.

Further, in the above two embodiments, the other party LA
When it was determined that early recovery could not be expected for all routes, the reason why the call to N failed was to just stop the recalling call. In this case, for the calling LAN, You may comprise so that the information for prohibiting or refraining from making a call to this other party's LAN may be transmitted.

[0058]

As described above, the inter-LAN connecting device of the present invention determines the disconnection reason code sent from the ISDN line network when the call to the other party's LAN fails, and disconnects this. If the reason code is a code that can be expected to recover early, the LAN side is automatically called again, and if it is a code that cannot be expected to recover early, it is configured not to call again, so it is extremely efficient. The LANs can be connected together.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a LAN-to-LAN connecting device according to a first embodiment of the present invention.

FIG. 2 is a network diagram showing the connection between the LAN connection device of FIG. 1 and each LAN.

FIG. 3 is a diagram showing an example of a call destination table of the LAN-to-LAN connecting device of the first embodiment.

FIG. 4 is a flowchart showing a processing procedure of the first embodiment.

FIG. 5 is a network diagram for explaining a second embodiment.

FIG. 6 is a diagram showing a configuration of a LAN-to-LAN connecting device according to a second embodiment.

FIG. 7 is a diagram showing an example of a call destination table of the LAN connection device of the second embodiment.

FIG. 8 is a flowchart showing a processing procedure of the second embodiment.

FIG. 9 is a network diagram in which LANs are connected by a conventional LAN connecting device.

[Explanation of symbols]

1 to 3 LAN (local area network) 10 ISDN line network 20 _{1 to} 20 ₃ LAN connection device 21, 22 interface 23 calling means 24 calling destination table 25 disconnection reason code determination means 26 recalling control means 30 ₁₁ to 30 ₃₃ LAN connection device 31 Call destination table 32 Different route call control means 33 Recall control means

Claims (1)

[Claims] 1. A local area network connected between an ISDN line network, and data from another local area network connected via said ISDN line network, received from said local area network, and said other local area. There is calling means for making a call to the network to the ISDN line network, and data is exchanged between the other local area network responding to the call and the local area network of the calling side. In the LAN-to-LAN connecting device that enables, when a call to another local area network by the calling unit fails, a disconnection reason code sent from the ISDN line network is received, and the disconnection reason code is regenerated. Disconnection reason code determining means for determining whether or not the call can be expected to be recovered early, and the disconnection When the reason code judging means judges that the disconnection reason code sent from the ISDN line network is a code that can be expected to be recovered early, the calling means makes the call to another local area network again. LA comprising re-call control means
Connection device between N.