JPH1146206A - Inter-network connection method for lan emulation and its system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent capabilities of LAN emulation from being deteriorated by distributing the loads of a bus, even with respect to increase in the number of LECs. SOLUTION: In an inter-network connection method, where LECs 10-10n, 11-11n, 12-12n are interconnected via an ATM network 18 and make data communication with each other, the LECs are grouped into groups A, B, C by each BUSs 13, 14, 15, each BUS shares broadcasting of the LECs in a same group, multi-cast relay ATM connection is set up with all the LECs, and a broadcast frame from the LECs of the same group is sent to all the LECs in the system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-network connection method in LAN emulation for setting a LAN emulation environment for connecting an existing LAN terminal to an ATM (asynchronous transfer mode) network, and a system therefor.

[0002]

[Related Background Art] Conventionally, LAN emulation has been standardized by the ATM Forum, which is an ATM standardization organization, and its current specification is version 1 (af-lane-0021.000) which has been standardized. ) Exists. In the above-mentioned ATM, since it is a connection type (a path connection type of an ATM cell switch), there is no concept of broadcasting. Therefore, in a LAN emulation environment in which a LAN is constructed on an ATM network, the BUS, which is the broadcast server, is used.
(Broadcast and Unknown Server) to realize broadcasting.

[0003] In a network environment setting system constructed in LAN emulation version 1, 1
One BUS is connected to the ATM network, and a client participating in LAN emulation transmits a frame (broadcast frame) to be transmitted as a broadcast to the entire LAN emulation to the BUS.

The BUS has an ATM connection for broadcast transmission and relay for all clients in LAN emulation. The BUS that has received the broadcast frame from a LAN emulation device such as a hub or an ATM terminal having a LAN emulation client function, for example, a so-called LEC (LAN Emulation Client), establishes a LAN that establishes the broadcast relay ATM connection.
A method of transmitting the frame to all LECs in the emulation has been used.

[0005]

However, in the above method, since only one BUS is provided in the LAN emulation, all L buses in the LAN emulation are provided.
There is a problem in that the load of the process of copying the above frame to the EC and relaying the same increases, the BUS occupation time for one broadcast frame becomes longer, and the frame transmission is delayed.

In the above method, the broadcast frames from all the LECs in the LAN emulation are concentrated on one BUS. Therefore, the number of broadcast frames flowing into the BUS increases as the number of LECs increases. As a result, the load on the BUS also increases, which leads to a decrease in the frame transmission capability of the entire system.

[0007] The present invention has been made in view of the above problems, and disperses the load of the BUS so that the LEC can be reduced even when the LEC increases.
It is an object of the present invention to provide a method and an apparatus for connecting between networks in LAN emulation for preventing a function deterioration of AN emulation.

[0008]

In order to achieve the above object, according to the present invention, there is provided an inter-network connection method for connecting LAN emulation devices composed of LECs via an ATM network and performing data communication with each other, and a device therefor.
Each of the LECs is divided into groups for each of the LECs connected to one ATM switch of the ATM network or a neighboring ATM switch, and the LECs of the group are assigned to a first server comprising a corresponding BUS, respectively. Establishes a multicast transmission ATM connection, which is a communication connection with the corresponding BUS, and performs the corresponding BUS
Transmits the broadcast frame to each of the BUs.
S has established a multicast relay ATM connection as a relay connection with all of the LECs, and upon receiving the broadcast frame from the LEC assigned to the own device, transmits the broadcast frame to all of the LECs in the system. And a second server composed of at least one LES for registering the address of each BUS in association with the identifier indicating the LEC assigned to the BUS in association with the ATM network. , The LES is the L
In response to an address request from the EC, the corresponding BUS
L which notifies the addresses of all the LECs in response to an address request from the BUS.
An inter-network connection method and an apparatus for the AN emulation are provided.

[0009] That is, LECs are divided into groups for each BUS, and each BUS shares the broadcasting of the LECs in the same group and transmits a broadcast frame to all LECs, thereby distributing the load. LES
Is provided corresponding to a plurality of groups among the groups, and registers at least an address of each BUS of the plurality of groups and an identifier indicating each LEC assigned to the BUS in association with each other. It has a registration table.

[0010] In addition, in response to an address request from the LEC newly joining the LAN emulation, the LES searches the registration table for the address of the corresponding BUS and notifies the BUS of the corresponding BUS. And the instruction for establishing the connection is transmitted, and the LEC of the new subscription transmits the corresponding BUS and the multicast transmission A based on the address of the received BUS.
The TM connection is established, and all the BUSs receiving the instruction establish the new joining LEC and the multicast relay ATM connection, respectively.

The LES searches and notifies the addresses of all the LECs in response to an address request from the BUS newly subscribed to the LAN emulation, and the newly subscribed BUS includes Then, all the LECs and the multicast relay ATM connection are respectively established. The LES is the LAN
When there is an LEC to be deleted from the emulation, an instruction to release the connection with the LEC is transmitted to all the BUSs, and all the BUSs receiving the instruction perform multicast relay with the LEC to be deleted. Release each ATM connection.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for connecting networks according to the present invention will be described with reference to FIGS. FIG.
FIG. 1 is a configuration diagram showing an embodiment of a system configuration using a method for connecting networks in LAN emulation according to the present invention. In the figure, in the present embodiment, LA
It has a client function of N emulation and a plurality of Ls assigned to each group A, B, C
ECs 10 to 10n, 11 to 11n, and 12 to 12n (n is an arbitrary integer), and BUSs 13, 14, and 15 that receive broadcast frames from LECs of a corresponding group among the LECs and relay the broadcast frames to all LECs. , An LES 16 for registering and managing the ATM address of the BUS in the system and an identifier indicating each LEC assigned to the BUS, and an ATM network 18 to which these devices are connected. . In an actual network connection, since a plurality of different systems exist in the ATM network, the LECS (LAN) for registering the identifier indicating each system in association with the ATM address of the LES in the system and the identifier indicating each LEC is associated. Emulation Co
nfiguration Server) 17 is also connected to the ATM network 18.

The groups A, B and C are, for example, ATM
In the present embodiment, the LECs 10 to 10n and the BUS 13 belong to the group A, and the LECs 11 to 11n and the BUS 14 belong to the group B.
LEC12-12n and BUS15 are group C
Shall belong to

Each of the LECs 10 to 10n, 11 to 11n, 1
Execution means 20 to 20n and 21 to 2 for executing the client function of LAN emulation.
1n, 22 to 22n, for example, a hub or an ATM terminal device. The execution means of each LEC obtains the ATM address of the LES 16 from the connected LECS 17 and obtains the ATM address of the BUS of the group to which the own device belongs from the connected LES 16, thereby performing multicast transmission with the BUS. An ATM connection is established (call setting), and a broadcast frame is transmitted. Further, when performing data communication of the point-to-point method, the execution means of each LEC obtains the ATM address of the counterpart LEC from the LES 16 to establish the connection with the counterpart LEC. To enable data communication. In addition,
This execution means follows the method of version 1 of LAN emulation, for example.

The BUSs 13, 14, 15 are provided by the establishing means 13
a, 14a, 15a, and establishing means 13a, 14a,
15a, all LECs 10-1 in the same system
A multicast relay ATM connection (call setting) is made in advance to 0n, 11 to 11n, and 12 to 12n.
Therefore, when the BUSs 13, 14, and 15 receive a broadcast frame from the LEC of the group to which the own device belongs using the multicast transmission ATM connection, the BUSs 13, 14, and 15 copy the frame and use the multicast relay ATM connection to transmit the frame. Can be relayed to each LEC in the system.

In this embodiment, one LES 16 is provided in the system, and the ATM of BUS of the same group is used.
It has a registration table 16a for registering addresses and identifiers indicating LECs in association with each other.
Notification means 16b for managing M addresses and LEC identifiers
The notification means 16b registers the corresponding BUS or LEC ATM address based on the address request in the registration table 1.
6a, and notifies the request source.

FIG. 2 shows a registration table 16 in the LES 16.
It is a figure showing each example of a component registered into a. In the figure, each example is an entry forming a pair in which the ATM address of the BUS and the identifiers of the LECs belonging to the same group are associated. Of the above entries, the entry is an ATM address of the BUS, for example, “39.39.2f.00.
01.02.03.04.05.06.07.08.09.0a.0b.0c.0d.0e.0f.00 ”
, And the L corresponding to the above address
This shows a case where an EC identifier, for example, an ATM address of the LEC is registered. The AT of the above LEC
The M address is a 20-byte address, for example, “47.00.
05.00.10.20.30.40.50.60.70.80.90.a0.b0.c0.d0.e0.f
0.00 ”, of which the first 13 bytes indicate the network prefix part and the remaining 7 bytes are each L
It is composed of information indicating a value unique to the EC.

As described above, there is a designation method in which LECs belonging to the same group are registered one by one in the BUS. However, the present invention is not limited to this, and more flexible designation is possible. For example, as shown in the entry of BUS
ATM address "39.39.2f.10.11.12.13.14.15.16.1"
For 7.18.19.1a.1b.1c.1d.1e.1f.00 ”, set to use the network prefix part of the ATM address of the LEC as the discrimination pattern without specifying the LEC identifier at all. In this case, when an inquiry about the BUS ATM address is made by the LEC in which the network prefix part of the ATM address is “39.39.2f.10.11.12.13.14.15.16.17.18.19”, Is the BU indicated in the entry having the same network prefix part.
A response is made with the ATM address of S as a search result.

As the LEC identifier, a part of the ATM address can be masked. For example, as shown in the entry, the BUS ATM address "39.39.2f.20.21.22.23.24.25.26.27.28.29.2a.2
For the b.2c.2d.2e.2f.00, the LEC identifier is "47.00.
05.02.12.22.32.42.52.62.72.82.92.a2.b2.c2.d2.e2.f
Consider the case where "XX" is specified, where "XX"
Indicates a masked byte, and any value may be inserted. In this case, if the first 19 bytes of the ATM address of the inquired LEC match the LEC identifier of the above entry, the ATM address of the paired BUS can be returned as a search result. .

Also, as shown in the entry, for example, an arbitrary number of the masks can be inserted into an arbitrary part of the LEC identifier. In the embodiment, the LEC
The identifier is “47.00.05.XX.XX.XX.33.43.53.63.73.83.X
X.a3.b3.c3.XX.XX.XX.00 ", the first to third bytes, the seventh to twelfth bytes, the fourteenth to sixteenth bytes, If all of the 20th byte matches the LEC identifier of the above entry, the ATM address “3” of the paired BUS
9.39.2f.30.31.32.33.34.35.36.37.38.39.3a.3b.3c.3d.
3e.3f.00 ”can be returned as a search result.

If the BUS ATM address corresponding to the inquired LEC identifier cannot be retrieved from the registration table 16a, a predefined B
It is also possible to respond with a US ATM address as a substitute. Thus, the notification means 16b of the LES 16
Is the BU registered in the entry in the registration table 16a in response to the address request control message from the LEC.
The ATM address of S can be returned as a search result.

FIG. 3 is a diagram showing an example of a frame format of a control message used in the present invention. In the figure, the control message includes a header section and a data section, both of which are based on the format of a control frame of version 1 of LAN emulation. The field of the above header part has a fixed value "FF
00 ”, a 1-byte protocol ID, a 1-byte LAN emulation version (in the embodiment, a fixed value of“ 01 ”), and a 2-byte control frame type (message Type) and an OP code indicating success or failure status
It is composed of a byte status, a 4-byte transaction ID sequentially assigned, a 2-byte requester ID assigned from the LES, and a 2-byte (fixed value of “0000” in the embodiment) flag. The field of the data part is a 20-byte source A indicating the ATM address of the node transmitting the request.
TM address and A of the target node of the address request
It indicates a TM address, for example, a target ATM address of several tens of bytes in consideration of a case where there are a plurality of nodes.

The protocol ID is a control message in the above-described LAN emulation version 1;
For example, in the case of a message in a configuration phase and an ARP transmission / reception phase between LEC and LECS, and in a join phase between LEC and LES, the message is set to “01”. On the other hand, in the case of the control message according to the present invention, for example, in the case of the message in the BUS join phase between the BUS and the LES and the address transmission / reception phase, it is set to BD (BUS Distribution).

In the case of the control message in the LAN emulation version 1, the OP code includes, for example, the configuration request and response (LE CONFIGURE).
REQUEST and LE CONFIGURE RESPONSE)
1 ”and“ 0101 ”are the request and response of the above join (LE JOIN
“0002”, “01” for REQUEST and LE JOIN RESPONSE)
02 ”, the ARP request and response (LE ARP REQUEST and LE
ARP RESPONSE) are set to “0006” and “0106”. It should be noted that only the OP code used in this embodiment is shown. Further, in the case of the control message according to the present invention, as shown in FIG. 4, for example, the request and response (LE BUS JOIN RE
“0001” for QUEST and LE BUS JOIN RESPONSE),
“0002” contains the address transmission / reception phase request and response (LE
"0003", "0004" for ADDRESS REQUEST and LE ADDRESS RESPONSE, and "0005" for an instruction (LE ADD LEC) requesting a newly added LEC to establish a multicast relay ATM connection. Requesting release of multicast relay ATM connection to LEC removed from LAN emulation and acknowledgment (LE RELEASE VCC and LE RELEASE VCC A
CK) are set to “0006” and “0007”, respectively.

It should be noted that the control message in the version 1 and the control message according to the present invention are distinguished by the protocol ID. Therefore, even if the OP code is the same, the control message is correctly recognized in the present embodiment. There is no. In addition, VCC of the above control message (LERELEASE VCC)
Is an abbreviation for virtual channel connection.
The requester ID is an ID assigned by the LES as described above, and is an LE that has requested the LES for an address or the like.
It is set for C and BUS and consists of 2 bytes of data.

The source address and the target address of the data portion in each of the above control messages of the present embodiment are, for example, the ATM address of the device shown in FIG. That is, the BUS join phase and the address transmission / reception phase are performed between the BUS and the LES,
The BUS ATM address is set as the source address, and the LES ATM address is set as the target address.
For other messages, the LES is set as the source address and the LEC address is set as the target address. However, in the case of the request control message, since the ATM address of the corresponding LES is unknown, "00" is set to 20 bytes as the target address. The addition and deletion of the LEC are performed between the LES and the BUS, and the ATM address of the LES is set as the source address and the ATM address of the LEC is set as the target address.

Next, a description will be given of the system operation when a new LEC joins the system of FIG. 1 as shown in FIG. 6, for example. 6, the same components as those in FIG. 1 are denoted by the same reference numerals for convenience of explanation. FIG.
8 is a system chart showing the operation of the entire system shown in FIG. 6, and FIGS. 8 to 10 show the newly added LEC,
6 is a flowchart illustrating operations of the LES and the BUS.

In FIG. 7 and FIG. 8, the LEC 19 newly added to the inter-network connection system of the present embodiment (hereinafter referred to as “new LEC 19”) is initially in the initial state, and then the conventional (the LAN emulation version 1). According to the method of (1), connection with an external device, for example, the LECS 17 is performed (step 101), and setting parameters are received from the external device, for example, the LECS 17 in the configuration phase (step 102). At this time, the control message transmitted / received to / from LECS 17 is LE
CONFIGURE REQUEST and LE CONFIGURE RESPONSE,
With this message, the new LEC 19 can obtain the ATM address of the LES 16 of the system to which the new LEC 19 belongs.

Next, the new LEC 19 makes a join request (LE JOIN REQUEST) for LAN emulation to the LES 16 in the join phase, and then receives a join request response (LE JOIN RESPONSE) from the LES 16 (step 103). Then, B of the group to which the own device belongs
In order to make a connection to the US, a control message (LE ARP
REQUEST) (step 104), and waits for reception of the response (step 105).

At this time, as shown in FIG. 9, the LES 16 stores the LE in which the ATM address of the new LEC 19 is included.
Upon receiving the ARP REQUEST, it is determined whether or not the registration table 16a has the Nth entry (step 20).
1). If there is an Nth entry, the source address of the inquiry message (LE ARP REQUEST), that is, the ATM address of the new LEC 19 is extracted, and the ATM of the LEC 19 is included in the entry.
It is determined whether there is an LEC identifier (address) corresponding to the address (step 202). If there is no N-th entry in the registration table 16a, a predefined BUS ATM address (default address) is used as a search result (step 203).

At step 202, if the LEC identifier in the entry does not include the ATM address of the inquired new LEC 19, the process proceeds to the next entry (step 204). To judge. The AEC of the new LEC 19 that has been queried is added to the LEC identifier in the entry.
If there is a TM address, the ATM address of the BUS (corresponding address) is set as a search result (step 20).
5).

The search results searched in steps 203 and 205 are a response to the inquiry of the new LEC 19,
That is, it is transmitted to the LEC 19 as a control message (LE ARP RESPONSE) (step 206). Also,
In this embodiment, all BUs in the LAN emulation
S sends a multicast relay A to the new LEC 19
Establish a TM connection. Therefore, LES16
After the search is completed, a control message (LE ADD LEC) for instructing all BUSes having entries in the registration table 16a to establish a multicast relay ATM connection to the new LEC 19 is transmitted (step 2).
07), the above operation ends.

As shown in FIG. 8, when the new LEC 19 receives the control message (LE ARP RESPONSE) from the LES 16 in the state of waiting for reception in step 105, the new LEC 19 uses the ATM address of the BUS contained in the message, and A multicast transmission ATM connection is established with the specified BUS (step 106). Next, the new LEC 19 waits for a multicast relay ATM connection from each BUS (step 1).
07).

When each of the buses 13 to 15 receives a control message (LE ADD LEC) indicating an instruction to connect to the new LEC 19 from the LES 16 as shown in FIG.
C19 is connected via the ATM network 18 to establish a multicast relay ATM connection (step 30).
1). Note that the multicast transmission ATM connection and the multicast relay ATM connection are UNI (Unique Access Protocol), which is a technique (protocol) used in a conventional call setup.
Signaling versions 3.0, 3.1, and 4.0 (A
TM Forum standard).

As shown in FIG. 8, when there is the connection, the new LEC 19 establishes a multicast relay ATM connection by connecting to the BUS (step 108), and finishes setting all necessary connections. It is determined whether or not it is (step 109). here,
If all the necessary multicast relay ATM connections have not been set up, the process returns to step 107 to wait for the next connection, and if all the necessary connections have been set up, the operation state is entered.

That is, in this embodiment, the LEC and the BU
S recognizes each other's ATM address based on the address included in the message transmitted from the LES, and establishes a connection.
The broadcast frame received from C is transmitted to another LEC.
It is possible to transmit to. In the present embodiment, B
When all necessary connections between the US and the LEC have been set up, the LEC can enter an operational state, which allows data communication with other LECs.

The transmission of the control message (LE ADD LEC) between the LES and the BUS in the present embodiment can be performed in a point-to-point system as long as the LES recognizes all the ATM addresses of the BUS of the communication partner. Alternatively, a point-to-multipoint method may be used. Next, the operation of the system when the LEC transmits a broadcast frame will be described.

In this case, each LEC has already established a multicast transmission ATM connection with the BUS of the same group by the operation shown in FIG. 8 when joining the system. Therefore, the LEC transmits the broadcast frame to the BUS through the connection.
Can be sent to When the BUS receiving the frame from the LEC determines that the frame is a broadcast, the BUS uses the multicast relay ATM connection previously established as described above, and
The broadcast frame is relayed to all LECs in the AN emulation.

Each LEC has a multicast relay ATM connection with all the BUSs in the LAN emulation, and can always receive the broadcast frame from any one of the BUSs. Therefore, in this embodiment, L
By selectively arranging the EC and the BUS among those connected to one node or a neighboring node, for example, one ATM switch or a nearby ATM switch, the path between each LEC and the BUS is shortened, Broadcast frames can be transmitted over the shortest distance.

In the present embodiment, the LEC having the multicast transmission ATM connection is limited to the BUS, and each LEC is assigned to a plurality of BUSs.
S can distribute the load involved in broadcasting, LEC
This can prevent the function of LAN emulation from deteriorating even if the number increases. Furthermore, in this embodiment, since the multicast relay ATM connection is directly established from the BUS to each LEC without passing through another BUS, the broadcast frame is an ATM fixed length packet → existing LAN data packet → ATM fixed. At most one conversion in the BUS, a long packet, the destination L
Can be sent to EC.

Next, the system operation when a new BUS joins the system of FIG. 1 as shown in FIG. 6, for example, will be described with reference to the system chart of FIG. BUS2 is newly added to the network connection system of this embodiment.
3 (hereinafter, referred to as “new BUS 23”), first, maintenance of the registration table 16a of the LES 16 is manually performed by, for example, an administrator.

In FIG. 11, when the ATM address of the new BUS 23 is added to the registration table 16a and a new entry is created, the LES 16 detects the joining of the new BUS 23 because the entry has changed. Next, the LES 16 establishes a topology information transmission connection between the LES and the BUS by the above-mentioned UNI signaling (ATM forum standard) which is a technique (protocol) used in the conventional call setting.

Using the above connection, the new BUS 23 sends a control message (LE BUS JOIN REQUEST) for declaring joining to LAN emulation to the LES 16, and the LES 16 sends a response control message (LE BUS JOIN REQUEST).
JOIN RESPONSE) to the new BUS 23. next,
The new BUS 23 is a control message (LE ADDRESS REQUEST) for inquiring the LES 16 about the ATM addresses of all LECs that have joined the LAN emulation.
Send Then, based on the target ATM address in the response control message (LE ADDRESS RESPONSE), the new BUS 23 establishes a multicast relay ATM connection to all LECs in the LAN emulation, and becomes operational.

In the present invention, the ATM address of the new BUS 23 can be automatically added to the registration table 16a of the LES 16. In this case, the new BU
In S23, it is necessary to set the ATM address of the LES 16 in advance. The new BUS 23 is based on the set LES 16 ATM address, and
A topology information transmission connection between the BUSs is established. After the establishment, the new BUS 23 sends a control message (LE BUS JOIN REQUEST) to L using the above connection.
Send to ES16.

LES 16 having received this message,
The entry of the new BUS 23 is automatically added to the registration table 16a. In this case, L in the registration table 16a
It is preferable not to register as an EC identifier, but to automatically associate it with an LEC having the same network prefix as that of the new BUS 23 (see the entry in FIG. 2).

The subsequent operation of the new BUS 23 is shown in FIG.
LES16 to LAN
ATM of all LECs participating in emulation
An address is obtained, and a multicast relay ATM connection is established with these LECs, and the operation becomes operational. Thus, the new BUS 23 can start a broadcast function of transmitting a broadcast frame received from an LEC belonging to the same group to all LECs. Further, after the BUS enters the operational state, when the above-described new addition of the LEC or the deletion of the LEC described later, which is a topology change of the LAN emulation, occurs, the multicast relay with the LEC is performed based on the instruction from the LES. It is possible to establish or release an ATM connection.

FIG. 12 is a relationship diagram showing a connection relationship between the respective devices. The disconnection of the connection with the LEC to be deleted will be described with reference to FIG. In the figure, ATM
Switch 25, LES24, BUS26 and LEC2
7, the connection C1 using the UNI signaling is established. In a LAN emulation environment, as described above, LE
S24-BUS26 topology information transmission connection C2, BUS26-LEC27 multicast transmission ATM connection C3 and multicast relay AT
Each of the M connections C4 is established via the ATM switch 25.

When the LES detects that the LEC has been deleted from the system, the LES uses the established topology information transmission connection C2 to change the ATM address of the LEC into a control message (LE RELEASE VC).
Send to all BUSes in the system, including in C). When each BUS receives the received message, the BUS
Using the method defined in the I signaling, the message indicating that the connection is to be disconnected is sent to the LE to be deleted.
C, and a multicast transmission A with the LEC
Release the TM connection C3 and the multicast relay ATM connection C4.

Further, BUS is a control message (LE REL
A control message (LE RELEASE V) for responding to release the connection with the LEC based on the EASE VCC)
CC ACK) to the LES. Accordingly, in this embodiment, when the LES recognizes the deleted LEC, the LES can transmit a message for disconnecting the connection to each BUS, so that the connection between the BUS and the LEC can be accurately released. it can.

In the above embodiment, one system is used for the same system.
Although the case where one LES is arranged has been described, the present invention is not limited to this. For example, a plurality of LES can be arranged in the same system. In these embodiments, the multicast relay ATM connection is point-to-
Although the case of the point method has been described, the present invention is not limited to this. For example, a connection of a point-to-multipoint method can be used.

In this case, the procedure by which the BUS establishes a multicast relay ATM connection for the LEC newly added to the system of the present invention is changed. That is, the LES sends an instruction (control message) for establishing a multicast relay ATM connection with the new LEC to the BUS, by sending the topology information transmission ATM.
Send on the connection. When the BUS receives this message, the BUS switches the multicast relay ATM connection to the new LEC to the existing multicast relay A.
It can be added as a leaf to the TM connection.

In this case, the procedure when a new BUS is added to the system of the present invention is also changed. That is,
When the new BUS receives the ATM addresses of all the LECs in the LAN emulation from the LES, the new BUS performs the work of adding each multicast relay ATM connection to those LECs as a leaf, and establishes the above connection. Can be.

[0053]

As described above, according to the present invention, each L
An AN emulation device is connected via an ATM network,
In an inter-network connection method for performing data communication with each other, each of the LAN emulation devices is divided into groups for each device connected to one ATM switch or a nearby ATM switch in the ATM network, and a LAN emulation device of the group is provided. Are respectively assigned to the corresponding first servers, and the LAN emulation apparatus has established a communication connection with the corresponding first server, and when performing the broadcast, the broadcast frame is transmitted to the corresponding first server. Each of the first servers has established a relay connection with all of the LAN emulation devices, and upon receiving the broadcast frame from the LAN emulation device assigned to itself, the first server All of the soil cast frame L
While transmitting to the AN emulation device, the ATM
The network is connected to at least one second server for registering the address of each of the first servers in association with an identifier indicating each of the LAN emulation devices assigned to the first server, and The second server notifies an address of the corresponding first server in response to an address request from the LAN emulation device, or all the LAN emulations in response to an address request from the first server. Since the address of the device is notified, the load on the BUS can be distributed, and the function of LAN emulation can be prevented from deteriorating even when the LEC increases.

According to a fourth aspect of the present invention, the second server notifies the address of the corresponding first server in response to an address request from a LAN emulation device newly subscribed to the LAN emulation. And transmitting an instruction to establish a relay connection with the LAN emulation device to the first server, and all the first servers receiving the instruction transmit the newly joined LAN
Since the relay connection is established with the emulation device, the first server can transmit the broadcast frame received from the LAN emulation device of the same group to another LAN emulation device.

According to a fifth aspect of the present invention, the second server notifies the addresses of all the LAN emulation devices in response to an address request from the first server newly subscribed to the LAN emulation. First
Server establishes a relay connection with all LAN emulation devices based on the notified address, respectively. Therefore, the new first server transmits a broadcast frame received from a LAN emulation device belonging to the same group to all LAN emulation devices. It can be sent to an emulation device.

In claim 6, the second server releases a relay connection with the LAN emulation device to all the first servers when there is the LAN emulation device to be deleted from the LAN emulation. All the first servers that have received the instruction release the relay connection with the LAN emulation device to be deleted, so that the connection between the first server and the LAN emulation device can be accurately established. Can be released.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a system configuration using an inter-network connection method according to the present invention.

FIG. 2 is a diagram showing each example of a component registered in a registration table in the LES shown in FIG. 1;

FIG. 3 is a configuration diagram showing an example of a frame format of a message used in the present invention.

FIG. 4 is a relationship diagram showing types of messages for the OP codes shown in FIG. 3;

FIG. 5 is a relationship diagram showing a source address and a target address for the message shown in FIG. 4;

FIG. 6 is a configuration diagram illustrating an example of a system configuration when an LEC and a BUS newly join the system of FIG. 1;

FIG. 7 is a system chart showing an operation of the entire system when the new LEC shown in FIG. 6 has joined.

FIG. 8 is a flowchart showing the operation of the new LEC at the initial stage.

FIG. 9 is a flowchart showing the operation of the LES at that time.

FIG. 10 is a flowchart showing the operation of the BUS at that time.

FIG. 11 is a system chart showing an operation of the entire system when the new BUS shown in FIG. 6 has joined.

FIG. 12 is a relationship diagram showing a connection relationship between devices.

[Explanation of symbols]

10 to 10n, ..., 12 to 12n, 27, 30a to 30
n, ..., 39a to 39n LEC 13 to 15, 23, 26, 42, 44 to 48 BUS 13a, 14a, 15a Establishing means 16, 24, 41, 43 LES 16a Notification means 16b Registration table 17, 40 LECS 18 ATM 20 -20a, 21-21a, 22-22a Execution means 25, 30-39 ATM switch

Claims (12)

[Claims] 1. Each LAN emulation device is connected to an ATM
A network connection method for connecting via a network and performing data communication with each other, wherein the LAN emulation devices are divided into predetermined groups, and the LAN emulation devices of the group are respectively assigned to corresponding first servers; The LAN emulation device includes the corresponding first
Has established a communication connection with the server, and when broadcasting, transmits the broadcast frame to the corresponding first server. Each of the first servers establishes a relay connection with all the LAN emulation devices. Each is established,
A method for connecting networks between networks in LAN emulation, wherein upon receiving the broadcast frame from the LAN emulation device assigned to the own device, the broadcast frame is transmitted to all the LAN emulation devices. 2. The LAN emulation device according to claim 1, wherein said LAN emulation device is a single ATM switch or a nearby ATM switch in said ATM network.
2. The network connection method in LAN emulation according to claim 1, wherein the devices are grouped for each device connected to the switch. 3. An ATM network in which at least one second registering an address of each of said first servers and an identifier indicating each of said LAN emulation devices assigned to said first server in association with each other. Servers are connected,
The second server notifies an address of the corresponding first server in response to an address request from the LAN emulation device, or all the LANs in response to an address request from the first server. 2. The device according to claim 1, wherein an address of the emulation device is notified.
3. A method for connecting between networks in LAN emulation according to item 1. 4. The second server notifies an address of a corresponding first server in response to an address request from a LAN emulation device newly subscribed to the LAN emulation, and transmits all the first servers. Transmitting an instruction to establish a relay connection with the LAN emulation device, and all the first servers receiving the instruction establish a relay connection with the newly added LAN emulation device, respectively. A method for connecting networks between networks in LAN emulation according to claim 1. 5. The second server notifies the addresses of all the LAN emulation devices in response to an address request from a first server newly subscribed to the LAN emulation. 5. The network connection method in LAN emulation according to claim 1, wherein the server establishes a relay connection with all LAN emulation devices based on the notified address. 6. The second server, when there is the LAN emulation device to be deleted from the LAN emulation, instructs all the first servers to release a relay connection with the LAN emulation device. 4. The transmission method according to claim 1, wherein all the first servers receiving the instruction release the relay connection with the LAN emulation device to be deleted.
5. The method for connecting networks in LAN emulation according to any one of 5. 7. Each of the LAN emulation devices is connected to an ATM.
In an inter-network connection system that connects via a network and performs data communication with each other, a communication connection is established with each of the LAN emulation devices of the same group, which is assigned to each of the LAN emulation devices divided into predetermined groups. And a relay connection is established with all the LAN emulation devices, and the L
A plurality of first servers for receiving a broadcast frame from the AN emulation device and transmitting the received broadcast frame to all of the LAN emulation devices; an address of each of the first servers; At least one of notifying an address of the corresponding first server in response to an address request from the LAN emulation device while registering the identifiers indicating the LAN emulation devices assigned to the same group in association with each other. A network connection system in LAN emulation, comprising: a second server. 8. An ATM switch in the ATM network or a nearby ATM switch in the ATM network.
8. The network connection system in LAN emulation according to claim 7, wherein the devices are grouped for each device connected to the switch. 9. The inter-network connection system registers an address of each of the first servers and an identifier indicating each of the LAN emulation devices assigned to the same group as the first server in association with each other. A table and a corresponding first server address in response to an address request from the LAN emulation apparatus, or all the LAN emulation apparatuses in response to an address request from the first server. Notification means for searching for and notifying the address of the
The network connection system in LAN emulation according to claim 7, further comprising two second servers. 10. The notifying means retrieves and notifies a corresponding first server address from the table in response to an address request from a LAN emulation device newly subscribed to the LAN emulation, and notifies the same.
An instruction to establish a relay connection with the LAN emulation device is transmitted to all the first servers, and all the first servers establish a relay connection with the newly added LAN emulation device in response to the instruction. 10. The network connection system in LAN emulation according to claim 9, further comprising establishing means for establishing. 11. The notification means searches for and notifies the addresses of all the LAN emulation devices in response to an address request from a first server newly subscribed to the LAN emulation. Server has the establishing means,
11. The network connection system in LAN emulation according to claim 10, wherein the establishing means establishes a relay connection with all of the LAN emulation devices based on the notified address. 12. The notifying unit, if there is the LAN emulation device to be deleted from the LAN emulation, sends the L to all the first servers.
Transmitting an instruction to release a relay connection with the AN emulation device, wherein the establishing means of all the first servers release the relay connection with the LAN emulation device to be deleted based on the instruction. A network connection system in LAN emulation according to any one of claims 9 to 11.