JPH0537569A - Inter-lan connection system by atm network - Google Patents

Abstract

PURPOSE:To reduce a frame transmission wait time by implementing prescribed processing depending on the result of collation between a destination address in a cell and a terminal equipment address in a storage table or on types of cells at the time of reception of a cell from an ATM network. CONSTITUTION:A broadcast VC broadcasting a cell sent from one TA3 to all other TA3 and an individual VC connecting the TA3 one to one are set among terminal adaptors TA3 (3a-3c). The TA3 is provided with an L-AFT storing an address of a terminal equipment 6 (6a-6c) connecting to a LAN 5 accommodating itself and an R-AFT storing VC identification connecting the address of the terminal equipment 6 accommodated by other TA3, itself and the other TA3 in pairs. Then the TA3 receiving the cell broadcasts the broadcast VC to the other TA3 based on the result of collation of a table and sends a cell by the individual VC to the TA3 having a reply. Thus, the call control processing at the time of frame transfer is not required to reduce the transfer wait time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for connecting LANs by means of an ATM switch forming an ATM network in order to perform communication between terminal devices connected to different LANs.

[0002]

2. Description of the Related Art FIG. 8 shows an ATM (Asynchronous Transfer) that divides data into fixed-length data units called cells and transfers the data in units of cells.
r Mode; asynchronous transfer mode)
It is a system block diagram in the case of connecting between N lines (Local Area Network) 5. FIG. In FIG. 8, 1a to 1c indicate the TA (Ter) for the LAN line 5, respectively.
AT accommodated via the Minal Adapter 3)
M exchanges A to C, 2 are ATM lines, 3a to 3c are LAN
TAa to c, which connect the line 5 to the ATM exchange 1, are L
AN lines 6a to 6c are terminal devices connected to the LAN line 5 via the transmission device 4. In the following description, one of the terminal devices 6a to 6c will be referred to as the terminal device 6.

FIG. 9 shows an M flowing on the LAN line 5.
This figure shows the configuration of an AC (Media Access Control) frame 7, and the MAC frame 7 has a destination address (DA [Destination Address Address]).
ss] 71, source address (SA [Source
Address]) 72 and an information section 73. FIG. 10 shows the configuration of the cell 8 transmitted to the ATM line 2. The cell 8 is a VCI (Virtual C).
It is composed of a header portion 81 including a channel identifier (logical channel identifier) 811 and an information portion 82.

Next, the operation of the conventional LAN-to-LAN connection system will be described. First, the MAC transmitted by the terminal device 6
The frame 7 is transmitted to the LAN line 5 via the transmission device 4. The TA 3 receives the MAC frame 7 from the LAN line 5, and inspects the DA 71 of the received MAC frame 7. If the DA 71 indicates the address of the terminal device 6 in the LAN accommodated in the own ATM exchange 1, the received MA
Discard C frame 7. DA71 is own ATM switch 1
If the address of the terminal device 6 in the LAN accommodated in is not shown, it is checked which TA3 is connected to the LAN to which the terminal device 6 having the address is connected, and the TA3 to which the received MAC frame 7 should be transmitted. To decide.

Next, the TA3 calls the own ATM exchange 1, and the own ATM exchange 1 that receives the TA3 should send TA3.
To the other ATM switching system 1 connected to. And
Both ATM exchanges 1 set a path so that the cell 8 is transmitted to the ATM exchange 1 on the receiving side. As a result, the TA 3 acquires the VCI 811 and divides the MAC frame 7 into one or more cells 8 of a certain length as shown in FIG. 11, and the cells 8 are the own ATM exchange 1 and the partner ATM exchange 1
Via TA to the other party's TA3. TA3 on the receiving side
From the sequentially received cells 8 to the MAC as shown in FIG.
The frame 7 is assembled and transmitted to the LAN line 5.

The MAC frame 7 is received by the terminal device 6 indicated by the DA 71 through the transmitting device 4. 1 M
When the transmission of all the cells 8 of the AC frame 7 is completed, the transmitting TA 3 disconnects the call, and the transmitting ATM switch 1 releases the route.

Regarding the conventional LAN-to-LAN connection method using an ATM switch, the IEICE technical report SS
E89-40 "Examination of ATM and MAN adaptation functions for LAN connection" (The Institute of Electronics, Information and Communication Engineers 1
(Published July 19, 989).

[0008]

Since the conventional LAN-to-LAN connection method using the ATM network is configured as described above,
The ATM switch 1 needs to perform a call control process for each MAC frame 7 to set and release the transmission path of the cell 8, and the transmission waiting time of the MAC frame 7 required for the call control process increases as the processing load increases. In addition, the transmitting side TA3 needs to have information for determining the receiving side TA3 connected to the LAN line 5 to which the destination terminal device 6 is connected. Therefore, the terminal device 6 connected to the LAN line 5 is required. When there are many numbers, there is a problem that it is necessary to have a huge amount of information.

The present invention has been made in order to solve the above problems, and it is not necessary to perform a call control process at the time of transferring the MAC frame 7, the transfer waiting time of the MAC frame 7 can be shortened, and TA3 In AT, it is unnecessary to set the information for associating the destination terminal device 6 and the TA3 connected to the LAN line 5 to which the terminal device 6 is connected.
The purpose is to obtain a LAN-to-LAN connection method using an M network.

[0010]

Means for Solving the Problems A according to the invention of claim 1
The LAN-to-LAN connection method using the TM network is a one-to-one correspondence between a broadcast type logical connection for broadcasting a LAN frame signal decomposed into cells between terminal adapters to all other terminal adapters, and each terminal adapter. Point-to-point logical connection to be connected to each terminal adapter, and each terminal adapter has a first address table that holds the addresses of all terminal devices connected to its own LAN, and terminal devices accommodated by other terminal adapters. And a second channel address table holding a logical channel identifier for identifying a logical connection connecting this terminal adapter and the other terminal adapter, and the terminal adapter receives the destination in the frame when receiving the frame from the terminal. Address and retained in each table A routine for collating the address of the terminal device and performing a predetermined process according to the collation result, and a predetermined result based on the collation result of the cell type or the destination address in the cell and the terminal device address in the holding table when the cell is received from the ATM network. And a routine for processing.

The LAN-to-LAN connection method using the ATM network according to the second aspect of the present invention is a broadcasting type in which a LAN frame signal disassembled into cells between terminal adapters is broadcast from one terminal adapter to all other terminal adapters. 1: 1 between logical connection and each terminal adapter
Set up point-to-point logical connection to connect to each terminal adapter
A first address table holding the addresses of all terminal devices connected to the terminal, the address of the terminal device accommodated by the other terminal adapter, and the logical channel identifier for identifying the logical connection connecting this terminal adapter to the other terminal adapter. When a frame is received from a terminal, the terminal adapter collates the destination address in the frame with the address of the terminal device retained in each table, and stores the destination terminal device according to the collation result. If it is not possible to identify the terminal adapter that is operating, the inquiry cell is sent to all other terminal adapters, and each divided data cell until the response cell is received from other terminal adapters is also sent by the broadcast logical connection. is there.

According to the third aspect of the present invention, there is provided an inter-LAN connection system using an ATM network, in which a LAN frame signal divided into cells between terminal adapters is broadcast from one terminal adapter to all other terminal adapters. Type logical connection and a point-to-point logical connection that connects each terminal adapter in a one-to-one relationship, and each terminal adapter has an LA that it accommodates.
A first address table holding the addresses of all terminal devices connected to N, and the address of the terminal device accommodated by another terminal adapter, and a logical channel for identifying the logical connection connecting this terminal adapter to the other terminal adapter It has a second address table provided with an area for holding an identifier and a timer value, and when the terminal adapter receives a frame from the terminal, it checks the destination address in the frame against the address of the terminal device held in each table. A routine for performing a predetermined process according to the collation result, and a routine for performing a predetermined process according to the collation result between the cell type or the destination address in the cell and the terminal device address in the holding table when the cell is received from the ATM network,
A routine for deleting from the table the terminal device that has not been in communication for a time exceeding the timer value is provided.

[0013]

According to the first aspect of the invention, when the terminal adapter transmits the data cell created by dividing the frame, if the terminal adapter accommodating the destination terminal device can be specified by the destination address, that terminal adapter is selected. The data cell is transmitted by a point-to-point logical connection, and if it cannot be specified, the inquiry cell is broadcast to all other terminal adapters and the route is determined by a simple exchange between the inquiry cell and the response cell. Also, AT
Upon receiving the cell from the M network, the terminal adapter checks the cell type, and if the cell is an inquiry cell, the second address table is updated if necessary if the relevant address is in its own LAN and the response cell is returned to the ATM. If not, the inquiry cell is discarded. If the cell is a response cell, the second address table is updated if necessary and the data cell is returned to the ATM network. If the cell is a data cell, it is assembled into a frame and transmitted in its own LAN.

According to the invention of claim 2, when the terminal adapter transmits the data cell created by dividing the MAC frame, the terminal adapter accommodating the destination terminal device can be specified as in the invention of claim 1. In the case, the data cell is transmitted to the terminal adapter by the point-to-point logical connection, and when the data cell cannot be specified, the inquiry cell is broadcast to all the other terminal adapters, and subsequently the data cell is broadcast. In addition, the terminal adapter which has received the cell from the ATM, according to the type of the cell and the collation with the address table, as in the invention of claim 1,
Returns or discards response cells or returns data cells.
If the cell is a data cell, the received data cell is assembled into a frame and then transmitted to the terminal device in the LAN.

According to the invention of claim 3, each terminal adapter has a first address table and a second address table as in the case of the invention of claims 1 and 2, and the second address is An area for holding the timer value is provided, and among the terminal addresses registered in the second address table, for the terminal device that has not been communicated for a certain period of time, the second address provided in the corresponding terminal adapter Delete the relevant address and logical connection identification in the table.

[0016]

EXAMPLES Example 1. An embodiment of the first invention will be described below with reference to the drawings. In this example. In the system configuration diagram shown in FIG. 8, between each TA3, a broadcast type logical connection (broadcast VC [Virtual1Connect) that broadcasts the cell 8 transmitted from one TA3 to all other TA3s.
point] and TA3 are connected one-to-one with point-to-point logical connections (individual VCs). Where TAa3a, TAb3b and TAc
3c has VCs of "1", "2" and "3", respectively.
It is assumed that I811 is associated.

When the cell 8 is broadcast from the TAa 3a by the broadcast type VC, the TAa 3a sends the VCI 811 of the cell 8 to the T
Set to "1" corresponding to A3 and send, TAb3b,
The TAc 3c receives the cell 8 of VCI811 "1".
When the cell 8 is transmitted from the TAa 3a to the TAc 3c by the individual VC, the TAa 3a sets the VCI 811 of the cell 8 to "3" and transmits the cell 8, and the TAc 3c receives the cell 8 of the VCI 811 "3".

As described above, when transmitting by the broadcast type VC,
The transmitting TA3 receives the cell 8 having the VCI 811 set by the value associated with the TA3, and the receiving TA3
Is the VCI set by the value associated with the transmitting side TA3
Receive cell 8 with 811.

Further, when transmitting by the individual VC, the transmitting side TA3 has a VCI having a value associated with the receiving side TA3.
The cell 8 in which 811 is set is transmitted, and the receiving side TA3 sets the VCI 811 set to the value associated with the transmitting side TA3.
Receive cell 8 with It is assumed that such a VC is set.

FIG. 1 is a block diagram of a local address filtering table (L-AFT) 9 and a remote address filtering table (R-AFT) 10 provided in the TA 3. The L-AFT 9 is a table that always holds the addresses of all the terminal devices 6 accommodated in its own TA3,
The R-AFT 10 is a table that holds the address of the terminal device 6 accommodated by another TA 3 and the VCI 811 indicating the VC on the TA 3 side by learning, in a terminal address area 1
01 and VCI area 102.

FIG. 2 shows an inquiry cell (INQ [INQu
cell) 8a, response cell (ANS [ANSwe
r] cell) 8b and a data cell (DATA cell) 8c created by dividing the MAC frame 7 in detail. These cells have the same configuration as in FIG. 10, but the header section 81 has a MID (Multiplexin).
g IDentifier) 812.

The INQ cell 8a has a VCI 811 and a MID.
It is composed of a header section 81 including 812, an information section 82 including DA 821 and SA 822. ANS cell 8b is V
Header section 81 including CI 811 and MID 812 and DA8
And an information section 82 including 21. The DATA cell 8c has a header portion 81 including a VCI 811 and a MID 812.
And an information section 82 including the divided MAC frame 7.

Here, the INQ cell 8a and the ANS cell 8b
And the DATA cell 8c is identified by the MID of the header section 81.
812, and thereafter the INQ cell 8a, ANS
The MID 812 of the cell 8b is set to "0" and "1", respectively, and the MID 812 of the DATA cell 8c is set to "0" and "1".
Assume other than.

In FIG. 3, TA3 is the L-LAN line 5 to the MA.
9 is a flowchart showing an operation when a C frame 7 is received. The operation will be described below with reference to the drawings. The DA 71 of the MAC frame 7 is searched for the L-AFT 9, and the DA 7 is searched.
1 exists in the L-AFT 9, the destination terminal device 6 determines
Since the A3 is accommodated, the MAC frame 7 is discarded. If it does not exist, it means that the destination terminal device 6 is accommodated by another TA3.
Split into. At this time, the DA 71 searches the terminal address area 101 of the R-AFT 10 and the DA 71 searches for the R-AF.
If it exists in the terminal address area 101 of T10, the value of the corresponding VCI area 102 is set to the VCI8 of the cell 8.
11, and the DATA cell 8c is transmitted to the TA3 accommodating the destination terminal device 6 by the individual VC. If it doesn't exist,
The INQ cell 8a is broadcast to all other TA3s by the broadcast type VC.

FIG. 4 is a flow chart showing the operation when the TA 3 receives the cell 8 from the ATM network. The operation will be described below with reference to the drawings.

First, the case where the received cell 8 is the INQ cell 8a will be described. DA of INQ cell 8a received
821 searches for L-AFT9 and the DA 821 is L-A
If it does not exist in the FT 9, the destination terminal device 6 discards the MAC frame 7 because the other TA 3 accommodates it. If the DA 812 exists in the L-AFT 9, it means that the own TA 3 accommodates the destination terminal device 6. Therefore, the SA 822 is searched for the R-AFT 10, and the SA 822 is searched.
Is not present in the R-AFT 10, the SA 822 and the VCI 811 of the INQ cell 8a are respectively set in the R-AF.
Terminal address area 101 and VCI area 10 of T10
Register in 2 (learn). And that VCI811
Is set in the ANS cell 8b and transmitted to the ATM network by the individual VC.

Next, the case where the received cell 8 is the ANS cell 8b will be described. DA of the received ANS cell 8b
821 and the VCI 811 of the ANS cell 8b are respectively registered (learned) in the terminal address area 101 and the VCI area 102 of the R-AFT 10. And that VC
I811 is set to DATA cell 8c and AT is operated by individual VC
Send to M network.

Finally, the received cell 8 is the DATA cell 8
The case of c will be described. Received DATA cell 8c
Is assembled into the MAC frame 7 and the TA3 connected to the L
Send to AN.

FIG. 5 shows the exchange of cells 8 and the L-AFT9 and R-AF in each TA3 when the MAC frame 7 is transmitted from the terminal device 6 accommodated in the TAa3a to the TAa3a.
It is explanatory drawing which shows the mode of T10. According to this explanatory diagram,
The cell transfer operation will be described. The terminal device 6a shown in FIG.
The case where the MAC frame 7 addressed to the terminal device 6c is transmitted is taken as an example. In addition, the L-AFT 9 of each TA 3 has the T
Addresses of all the terminal devices 6 accommodated in A3 are registered, no information is registered in the R-AFT 10, and each MAC frame 7 is divided into two cells 8. To do.

LA accommodated in the ATM exchange A1a
Assuming that the terminal device 6a connected to the N line transmits the MAC frame 7, first, the TAa 3a sends the MAC frame 7.
Receive frame 7. MAC frame 7 for TAa3a
Examine the content "c" of DA71. Here, “c” of DA 71 indicates the terminal device 6c. DA71
Since "c" is not registered in either the L-AFT 9a or the R-AFT 10a, the INQ cell 8a is created.
The VCI811 of the INQ cell 8a is "1" which is the VCI811 corresponding to TAa, and the MID812 is INQ.
"0" indicating the cell 8a, MA in DA821
The content “c” of DA71 of C frame 7 and the content “a” of SA72 of MAC frame 7 are set in SA822.

TAa3a is the INQ set as above.
The cell 8a is transmitted to the ATM exchange A1a by the broadcast type VC,
This ATM exchange A1a and other ATM exchanges B and C
Broadcast to all other TA3 by (1b, 1c).

TAb, c (3b, 3c) are L-AFT (9) at DA821 of the received INQ cell 8a, respectively.
b, 9c) and if registered, ANS cell 8b
To create. At that time, the SA 822 of the INQ cell 8a becomes R
-If it is not registered in the AFT 10, register the SA 822 and the corresponding VCI 811. DA821
Since "c" indicates the terminal device 6c, only the TAc 3c creates the ANS cell 8b. VC of ANS cell 8b
I811 has the same value "1" as the VCI 811 of the received INQ cell 8a, MID 812 has "1" indicating that it is the ANS cell 8b, and DA821 has the same value "c" as the DA821 of the received INQ cell 8a. To set.

Further, the SA 822 of the INQ cell 8a is R-
Since it is not registered in AFT10c, its SA822
"A" is registered in the terminal address area 101c, and the corresponding VCI 811 "1" is registered in the VCI area 102c. Then, the ANS cell 8b is set to TAa
Return to. Since the ANS cell 8b is transmitted by the individual VC, the VCI 81 of the transmission source is transmitted by the ATM exchange C1c on the transmission side.
1 "3" converted to TAa3a VCI811 "3"
Arriving at.

The TAa 3a receives the ANS cell 8b, divides the MAC frame 7 into two, and outputs the DATA cell 8c.
To create. The VCI 811 of the DATA cell 8c has the same value "3" as the VCI 811 of the received ANS cell 8b,
A value "2" other than "0" and "1" indicating the DATA cell 8c is set in the MID 812. Further, the DA “c” 821 of the ANS cell 8b is the R-AFT 10a.
Is registered in the terminal address area 101a and the corresponding VCI 811
"3" is registered in the VCI area 102a. And 2
One DATA cell 8c is transmitted to TAc3c by individual VC. Since these DATA cells 8c are transmitted by individual VCs, the ATM switch A1a on the transmission side transmits the VCI8 of the transmission source.
11 Converted to “1” and VCI811 is set in TAc3c
Reach with "1".

The TAc 3c assembles the received DATA cell 8c into a MAC frame 7 as shown in FIG.
Send to LAN.

Example 2. An embodiment of the invention of claim 2 will be described below. In this embodiment, as described in claim 1, each T in the system configuration diagram shown in FIG.
A broadcast VC and an individual VC are preset between A3, and each TA3
The L-AFT 9 and the R-AFT 10 shown in FIG. 1 are provided to exchange the INQ cell 8a, the ANS cell 8b and the DATA cell 8c shown in FIG.
It operates like.

FIG. 6 shows a terminal device 6 housed in the TAa 3a.
From the TA 8a to the TAa 3a, the data check of the cell 8 and the l-AFT 9 in each TA3,
It is explanatory drawing which shows the mode of the data search in R-AFT10.

With the above description, the operation will be described.
Similarly to claim 1, the case where the terminal device 6a shown in FIG. 8 transmits the MAC frame 7 for the terminal device 6c is taken as an example. The addresses of all the terminal devices 6 accommodated in the TA 3 are registered in the L-AFT 9 of each TA 3, and no information is registered in the R-AFT 10.
Each MAC frame 7 is assumed to be divided into two cells 8.

LA accommodated in the ATM exchange A1a
If the N terminal device 6a sends out the MAC frame 7, first, the TAa 3a receives the MAC frame 7. The TAa 3a checks the DA 71 "c" of the MAC frame 7. Here, “c” of DA 71 indicates the terminal device 6c. DA71 "c" is L-AFT9a, R
-Because it is not registered in either of AFT10a, I
Create the NQ cell 8a. VCI of the INQ cell 8a
811 is VCI811 corresponding to TAa3a “1”, MID812 is INQ cell 8a “0”, DA821 is DA7 of MAC frame 7.
1 "c", SA822 is SA72 of MAC frame 7
Set "a". The TAa 3a transmits the INQ cell 8a set as described above to the ATM exchange A1a by the broadcast type VC, and broadcasts to all other TA3s by this ATM exchange A1a and the other ATM exchanges B, C (1b, 1c).

Subsequently, the TAa 3a divides the MAC frame 7 to create a DATA cell 8c. The DAT
VCI8 corresponding to TAa is added to VCI811 of cell 8c.
11 is "1", and MID 812 has a DATA cell 8c.
The value "2" other than "0" and "1" indicating that there is is set. The TAa3a is the DATA cell 8 set as above.
a is transmitted to the ATM exchange A1a by a broadcast type VC, and the A
TM exchange A1a and other ATM exchanges B, C (1
b, 1c) to all other TA3s.

TAb, c (3b, 3c) receives the INQ cell 8a, and the DA 821 of this INQ cell 8a.
Since "c" indicates the terminal device 6c, only the TAc 3c creates the ANS cell 8b. VC of ANS cell 8b
I811 has the same value "1" as the VCI 811 of the received INQ cell 8a, MID 812 has "1" indicating that it is the ANS cell 8b, and DA821 has the same value "c" as the DA821 of the received INQ cell 8a. To set. Further, since the SA 822 of the INQ cell 8a is not registered in the R-AFT 10c, the SA 822 "a" is set to the terminal address area 101c and the corresponding VCI 811 is set.
"1" is registered in the VCI area 102c. And A
The NS cell 8b is returned to the TAa 3a by the individual VC. AN
Since the S cell 8b is transmitted by the individual VC, the AT on the transmitting side
The M switch C1c converts the transmission source VCI to "3" 811 and arrives at the TAa 3a at VCI 811 "3".

TAa 3a receives the ANS cell 8b, and divides the MAC frame 7 to create the remaining DATA.
In the cell 8c, the VCI 811 has the same value "3" as the VCI 811 of the received ANS cell 8b, the MID 812.
"0", "1" indicating that it is a DATA cell 8c
Set a value other than "2". In addition, the ANS cell 8b
Since the DA 822 “c” of No. is not registered in the R-AFT 10a, the DA 822 “c” of the
a, and the corresponding VCI811 "3" is registered in the VCI area 102a. And this DATA cell 8c
Is transmitted to TAc3c by individual VC.

Since the DATA cell 8c is transmitted by the individual VC, the VC of the transmission source is transmitted by the ATM exchange A1a on the transmission side.
I811 converted to "1" and VCI811 in TAc3c
Arriving at "1".

The TAc 3c assembles the received DATA cell 8c into a MAC frame 7 as shown in FIG.
Send to LAN.

Example 3. An embodiment of the invention of claim 3 will be described below with reference to the drawings. FIG. 7 is a diagram showing an R-AFT 11 in which a timer value area 103 is newly added to the R-AFT 10 of FIG. 1 used in claims 1 and 2. In the present invention, by providing the concept of a timer value, R
-Among the terminal addresses registered in AFT11, the terminal address which has not been communicated for a certain period of time is R-AFT1.
It is to be deleted from 1.

Next, a specific operation will be described. A predetermined timer value is set in advance, and the terminal address and the corresponding VCI 811 are registered or updated (when the MAC frame 7 is received from the LAN, the DA 71 of the MAC frame 7 is registered).
Is already registered in the R-AFT 11, or it receives the DATA cell 8c from the ATM network and sends it to the MA.
Each time when the SA 72 of the MAC frame 7 is already registered in the R-AFT 11 when assembled in the C frame 7, the specified timer value is set in the timer value area 10.
3 is re-registered, and all the registered timer values are periodically subtracted. Then, when the timer value becomes “0”, the terminal address corresponding to the timer value and the VCI 811 paired with the terminal address are deleted (actually,
It is a terminal address value that means delete).

[0047]

As described above, according to the first aspect of the invention, the LAN is divided into cells between the terminal adapters.
A broadcast-type logical connection that broadcasts a frame signal from one terminal adapter to all other terminal adapters and a point-to-point logical connection that connects each terminal adapter in a one-to-one relationship are set. A first address table holding the addresses of all terminal devices connected to the accommodated LAN, the address of the terminal device accommodated by another terminal adapter, and the logical connection connecting this terminal adapter to the other terminal adapter It has a second address table holding logical channel identifiers, and the terminal adapter, when receiving a frame from a terminal, collates the destination address in the frame with the address of the terminal device held in each table, and determines a predetermined value based on the collation result. A routine for processing A data cell received from the terminal adapter terminal is provided by providing a routine for performing a predetermined process according to the result of matching the cell type or the destination address in the cell with the terminal device address in the holding table when the cell is received from the M network. When the other terminal adapter to be transmitted cannot be specified, the inquiry cell is sent to all other terminal adapters by the broadcast type logical connector, and the data cells that compose the frame by the point-to-point logical connection are applied to the terminal adapter that responded to the cell. Since the configuration is such that the frame is transmitted to the terminal adapter, there is no need to perform call control processing at the time of frame transfer, and there is an effect that the frame transfer waiting time can be shortened.

According to the second aspect of the invention, between the terminal adapters, a broadcast type logical connection for broadcasting a LAN frame signal decomposed into cells from one terminal adapter to all the other terminal adapters, and each terminal adapter. Set the point-to-point logical connection that connects between the terminals one to one, and each terminal adapter,
The first address table that holds the addresses of all terminal devices connected to the LAN that it accommodates, the address of the terminal device that the other terminal adapter accommodates, and the logical connection that connects this terminal adapter to the other terminal adapter It has a second address table holding a logical channel identifier for identification, and when the terminal adapter receives a frame from a terminal, it compares the destination address in the frame with the address of the terminal device held in each table and If the terminal adapter accommodating the destination terminal device cannot be identified, the inquiry cell is sent to all other terminal adapters, and each divided data cell until the response cell is received from other terminal adapters is also a broadcast logical connection. I decided to send it from It is possible to shorten the transfer latency of the arm, there is an effect that it is possible to reduce the transfer delay time of the frame by shortening the transmission period of the data cell.

According to the invention of claim 3, a broadcast type logical connection for broadcasting a LAN frame signal divided into cells between the terminal adapters to all the other terminal adapters, and each terminal. A point-to-point logical connection for connecting the adapters in a one-to-one manner is set, and each terminal adapter has a first address table holding the addresses of all terminal devices connected to the LAN accommodated by itself and other terminals. The address of the terminal device accommodated by the adapter, the logical channel identifier for identifying the logical connection connecting this terminal adapter and the other terminal adapter,
It has a second address table provided with an area for holding the timer value, and when the terminal adapter receives a frame from the terminal, it collates the destination address in the frame with the address of the terminal device held in each table, and the collation result A routine for performing a predetermined process according to the above, a routine for performing a predetermined process according to the result of collating the cell type or the destination address in the cell with the terminal device address in the holding table when the cell is received from the ATM network, and the timer value. With respect to the terminal device which has not been communicated for a time exceeding the above, by providing a routine for deleting from the table, the terminal address which has not been communicated for a certain period of time among the terminal addresses registered in the second address table By deleting the logical connection identification paired with the terminal address from the second address table, Without providing the area of the total number of terminal addresses in the address table, there is an effect that can be efficiently used in small areas.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a local address filtering table (L-AFT) and a mote address filtering table (R-AFT) provided in a TA.

FIG. 2 is a detailed format diagram of each cell.

FIG. 3 is a flowchart showing an operation when a TA receives a MAC frame from a LAN.

FIG. 4 is a flowchart showing an operation when a TA receives a cell from an ATM network.

FIG. 5 is an explanatory diagram showing how cells are transmitted and changes of L-AFT and R-AFT in each TA in the invention of claim 1;

FIG. 6 is an explanatory diagram showing how cells are transmitted and changes of L-AFT and R-AFT in each TA in the invention of claim 2;

FIG. 7 is a configuration diagram of an R-AFT capable of performing a deletion process in the invention of claim 3;

FIG. 8 is a LAN by an ATM exchange forming an ATM network.
It is a system configuration diagram in the case of performing inter-connection.

FIG. 9 is a configuration diagram of a MAC frame.

FIG. 10 is a configuration diagram of a cell.

FIG. 11 is a room configuration diagram showing how a TA divides a MAC frame into cells.

FIG. 12 is a room configuration diagram showing how the TA assembles cells into MAC frames.

[Explanation of symbols]

1 ATM exchanges 1a-1c 3 TA3a-3c 5 LAN line 6 terminal devices 6a to 6c 9 L-AFT 10 R-AFT 11 R-AFT with deletion function 103 timer value area

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 8529-5K H04L 11/20 Z

Claims (3)

[Claims] 1. In a LAN-to-LAN connection system using an ATM network in which each of a plurality of ATM exchanges constituting an ATM network accommodates a LAN to which a terminal device is connected via a terminal adapter, a cell is provided between the terminal adapters. A broadcast type logical connection for broadcasting the divided LAN frame signals from one terminal adapter to all other terminal adapters and a point-to-point logical connection for connecting each terminal adapter in a one-to-one manner are set, and each terminal adapter is set. Is a first address table that holds the addresses of all terminal devices connected to the LAN that it owns, the addresses of the terminal devices that other terminal adapters accommodate, and the logic that connects this terminal adapter to the other terminal adapters described above. Logical channel identification to identify the connection The terminal adapter has a second address table holding the child, and when the frame is received from the terminal, the terminal adapter collates the destination address in the frame with the address of the terminal device held in each table, and performs a predetermined process according to the collation result. ATM and a routine for performing a predetermined process when the cell is received from the ATM network, based on the collation result of the cell type or the destination address in the cell and the terminal device address in the holding table.
LAN-to-LAN connection method. 2. In a LAN-to-LAN connection system using an ATM network in which each of a plurality of ATM exchanges forming an ATM network accommodates a LAN to which a terminal device is connected via a terminal adapter, the terminals are disassembled into cells. A broadcast type logical connection for broadcasting the generated LAN frame signal from one terminal adapter to all the other terminal adapters and a point-to-point logical connection for connecting each terminal adapter in a one-to-one manner are set. , A first address table that holds the addresses of all terminal devices connected to its own LAN, and the addresses of the terminal devices that are accommodated by other terminal adapters, and the logical connection that connects this terminal adapter to the other terminal adapters described above. Channel identifier that identifies the When a frame is received from a terminal, the terminal adapter collates the destination address in the frame with the address of the terminal device retained in each table, and stores the destination terminal device according to the collation result. When it is not possible to identify the terminal adapter that is operating, the inquiry cell is sent to all other terminal adapters, and each divided data cell is also sent by the broadcast logical connection until a response cell is received from the other terminal adapter. A method for connecting between LANs using an ATM network. 3. An inter-LAN connection system using an ATM network in which each of a plurality of ATM exchanges constituting an ATM network accommodates a LAN to which a terminal device is connected via a terminal adapter, and the terminal adapter is divided into cells. Each terminal adapter is configured by setting a broadcast type logical connection for broadcasting the generated LAN frame signal from one terminal adapter to all other terminal adapters and a point-to-point logical connection for connecting each terminal adapter in a one-to-one relationship. Is a first address table that holds the addresses of all terminal devices connected to the LAN that it owns, the addresses of the terminal devices that other terminal adapters accommodate, and the logic that connects this terminal adapter to the other terminal adapters described above. Logical channel identification to identify the connection It has a second address table provided with an area for holding a child and a timer value. When the terminal adapter receives a frame from the terminal, the terminal adapter compares the destination address in the frame with the address of the terminal device held in each table. A routine for performing a predetermined process according to a collation result, a routine for performing a predetermined process according to a collation result of a cell type or a destination address in the cell and a terminal device address in a holding table when a cell is received from an ATM network, A LAN-to-LAN connection method using an ATM network, which has a routine for deleting from a table a terminal device that has not been in communication for a time exceeding a timer value.