JP3349725B2 - LAN connection control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-LAN connection control method for providing a wide-area inter-LAN connection service in a broadband network. And other LANs
The present invention relates to an inter-LAN connection control method in a system including semi-permanent connection means (PVC) in which a connection with an interconnection device is preset by a broadband switching network.

In recent years, broadband exchanges have been developed,
Research on TM exchanges has been actively conducted for practical use. For such a broadband exchange, the LAN connection service is considered as one of the most effective applications. In the United States, Bellcore is studying SMDS (Switched Multi-megabit)
Data Service) is one of the high-speed LAN connection services.

In order to provide a high-speed LAN-to-LAN connection,
Basically, all PVCs (Per-
It is possible to cope with this problem by connecting them with a manent virtual circuit), but since resources inside the broadband switching network are almost exclusively used for connection between LANs, it is necessary to avoid this.

[0004]

2. Description of the Related Art Although the technology of broadband switching (especially ATM switching) has not reached the stage of providing an actual service, a configuration conceivable when the conventional technology for connection between LANs is simply applied to a broadband switching network. Is shown in FIG. 10 as a conventional example.

In FIG. 10, a plurality of LAN subscribers are accommodated in a large number of LANs a to h, respectively. When a subscriber accommodated in each LAN communicates with a subscriber accommodated in another LAN, a wide band is used. It connects to the LAN connection device via a network (ATM network), and the LAN connection device connects to a subscriber accommodated in another LAN. Basically, the LAN connection device is accommodated in a broadband network (ATM network). And B. It can be roughly divided into the following two configurations.

A. Are all the LAN connection devices 100 to
At 102, all LANs (and thus all subscribers) a through h
Is a full mesh system in which a connection path is formed so as to be accommodated. In this case, all paths between each LAN and the LAN-to-LAN connecting device are performed using paths registered in advance as PVCs (including upstream and downstream). The PVC does not perform VC (Virtual Call), which is a procedure for setting up a call, but registers the logical channel setting to be performed in the call setting in an ATM exchange in advance, and sets up a call setting in the case of a communication partner in which the PVC is set up. You can communicate immediately without having to do it. Also, the registered logical channel is not used as reserved for other call settings.

In this method, a subscriber of a certain LAN sends L
The information transmitted through the inter-AN connecting device is based on A of the broadband network.
The TM exchange determines the LAN-to-LAN connecting device that handles the least traffic by traffic management, and transfers information using the corresponding PVC.
Perform routing based on the destination address.

B. Are connected only to the nearest inter-LAN connecting device. In the figure, LANa to c are connected to the inter-LAN connecting device 100, and LANd and e are connected to the inter-LAN connecting device 10.
1 and so on, and each LAN connection device 10
0 is connected to an adjacent LAN connection device. Also in this case, the logical channels between the LANs and the LAN-to-LAN connecting devices and between the LAN-to-LAN connecting devices are the same as those in the above-described A.I. Is registered in advance in the ATM network (ATM exchange) as PVC.

In this method, the data is sequentially transferred from the source LAN subscriber to the inter-LAN connecting apparatus accommodating the designated destination, and finally, the L to which the destination subscriber is accommodated is transferred.
The information will be carried to the AN.

[0010]

In the conventional example shown in FIG. In the method of (1), a large number of PVCs are set up for connecting the LAN and the LAN-to-LAN connecting device, so that many resources (switches and transmission line bandwidth) of the broadband exchange are exclusively used for the LAN-to-LAN connection, and a high-speed LAN-to-LAN service is provided. Can be provided, but has the problem of affecting VC-based services using other normal call setup procedures. On the other hand, B. In the method of (1), since the traffic of the inter-LAN connecting device is concentrated for detour, it is necessary to prepare a thick bundle (large-capacity path) in a broadband network. Although it is not as high as the above method, resources will be occupied.
Further, since the inter-LAN connecting devices are connected in multiple stages, A.I. There is a problem that the connection cannot be speeded up as compared with.

An object of the present invention is to provide an inter-LAN connection control method capable of providing a high-speed inter-LAN connection service while saving the use of resources of a broadband switching network.

[0012]

FIG. 1 is a diagram illustrating the principle of the present invention. In FIG. 1, reference numeral 1 denotes a starting LAN accommodating a starting subscriber, 2 denotes a broadband network, and 3 to 5 denote LAN-to-LAN connecting devices each accommodating the nearest LAN. LAN connection device that accommodates
Is an inter-LAN connecting device adjacent to the inter-LAN connecting device 3, 5
Is an inter-LAN connecting device accommodating the LAN of the activation destination (recipient) subscriber, and 6 is an activation destination LA accommodating the activation destination subscriber.
N.

The present invention relates to FIG. Based on
As a means for reducing the resources of the LAN-to-LAN connecting device, a path for information (uplink information) from the first activation source is set to each L.
The connection device between the ANs is sequentially activated by the PVC by the L of the subscriber to be activated.
The path of information (downlink information) from the inter-LAN connecting device accommodating the AN to the inter-LAN connecting device accommodating the LAN of the activation source subscriber is connected on a VC basis (by call setting). It is formed by the connection request by.

[0014]

When a subscriber of the activation source LAN 1 requests connection with a subscriber accommodated in another LAN as an activation destination (destination), the activation source LAN 1 is connected to the broadband network (ATM switching network) 2 by the nearest LAN. It is connected to the connection device 3. The path in this case is registered in advance as PVC. Upon receiving this request, the LAN-to-LAN connecting device 3 checks whether or not the plurality of LANs contained in the own device include the requested start-up LAN.
Connect. When the LAN 6 to be activated is not accommodated in the inter-LAN connecting device 3, the request is transferred using the path of the adjacent inter-LAN connecting device 4 in which the PVC is set. At this time, the inter-LAN connecting apparatus accommodating the activation source LAN assigns its own address to the transferred information.

Receiving this, the adjacent LAN connecting device 4 similarly determines whether the LAN to be activated is accommodated in its own device.
The address given by the inter-LAN connecting device 3 at this time is transferred without change. If it is found that the inter-LAN connecting device 5 accommodates the boot destination LAN, an upstream and downstream path is formed between the boot destination LAN and the local area network using PVC.

The transfer path of the information in the upward direction from the inter-LAN connecting device 3 to the inter-LAN connecting device 5 via the inter-LAN connecting device 4 is formed sequentially through the PVC as described above. The path for transferring the downstream information from the connection device 5 to the LAN connection device 3 does not use PVC, and
Using the address of the inter-LAN connecting device 3 (included in the information received via the upstream path) from the inter-connecting device 5 to the broadband network 2, a call setting request is made by a normal VC. Then, a VC path is formed as shown in FIG.

The LAN that has received this downstream path connection request
Connection device 3 (L which is first received from the activation source LAN
When the inter-AN connection device determines that there is no traffic for a certain period of time by monitoring the downstream traffic, it issues a request to disconnect the corresponding VC for which connection has been requested, and releases the path.
As a result, the capacity occupied by the PVC between the LAN-to-LAN connecting devices is increased by the conventional B.B. As described above, there is no need to exclusively occupy the path between the LAN connection devices for the up / down of the PVC in advance, so that the capacity can be reduced to half and the resources of the broadband network are not wasted.

This is because in network design,
Since it is necessary to consider that traffic for the subscribers not accommodated by one LAN connection device flows, a considerable amount of path capacity is required. It is also effective. In addition, one LAN connecting device itself can also reduce the input / output capacity for connecting the LAN connecting device, and by allocating this amount to the subscriber, the network can be viewed as LA.
The number of the N-to-N connection devices can be reduced. Further, thereby, the speed of the LAN connection service can be increased.

[0019]

FIG. 2 is a system configuration diagram in which the present invention is implemented.
3 is a configuration diagram of LAN data and cells, FIG. 4 is a configuration diagram of an embodiment of an inter-LAN connecting device, FIGS. 5 and 6 are control flows in the inter-LAN connecting device, and FIG. 7 is a configuration diagram of each table.

FIG. 2 shows the system configuration of the broadband network as A.I. And B. Are shown. A. Is a form in which a single ATM exchange accommodates a plurality of inter-LAN connecting devices to provide a service. That is, the ATM switch 2
A plurality of LANs are accommodated in the ATM switch 20 via an ATM interface via an ATM-compatible router (a device having a bridge and a router), and a plurality of LAN connecting devices 21-1. A subordinate LAN is allocated and accommodated in the ATM exchange 20. Each LAN serves as an up / down PV as a path for transferring information with the assigned inter-LAN connecting device.
The path C is registered in the ATM switch 20.

Further, the LAN connection devices 21-1 to 21-
In the case of n, a PVC is registered for a path for transferring uplink information connected to an adjacent LAN connection device in order. In addition,
The upstream PVC from one LAN connection device to the other LAN connection device and the upstream PVC from the other LAN connection device to one LAN connection device are registered. These two paths are registered between each LAN. They are treated as upstream paths in the connection device and are independent of each other.

FIG. Is a form in which a plurality of LAN exchange devices are accommodated in a plurality of ATM exchanges. Only two ATM exchanges 20-1 and 20-2 are shown in FIG. By connecting, an arbitrary number of ATM switches are configured. Each of the ATM exchanges is provided with inter-LAN connecting devices 21-1 and 21-2. In each of the inter-LAN connecting devices, an arbitrary number of LANs are accommodated in the connected ATM exchange (in the case of B., the ATM exchanges 20-1-2). The LAN accommodated in 2 is not shown.

Each LAN is connected to a LAN-to-LAN connection device provided in an ATM exchange accommodating the LAN and an up / down PV.
Connected by C. Each inter-LAN connecting device has its upstream path registered with an ATM exchange accommodating its own device and an upstream path with the inter-LAN connecting device accommodated in an adjacent ATM exchange. From the other LAN connection device, one L
The upstream PVC is registered in the AN connection device.

When the ATM switch requests a PVC logical channel registered by the existing technology, the ATM switch immediately allocates a logical channel to the call and forms a path. A path is formed by searching for a free logical channel by bilink.

FIG. 3 shows the structure of LAN data and cells.
The LAN data transmitted between the LANs is shown in FIG. 3A. When the LAN data is transmitted from the LAN subscriber, the data is transmitted to the header and the payload (when the LAN data is transmitted) as shown in FIG. ) Are assembled into fixed-length cells (or ATM cells), and the number of cells corresponding to the data length of LAN data is generated. When the information transferred to the LAN subscriber in the form of a cell is transmitted from the ATM exchange to the LAN subscriber, the cell shown in b is disassembled by an ATM-compatible router and the original a is removed except for the header. Is restored to such LAN data.

FIG. 3c shows a conventional Ethernet frame structure as a specific example of LAN data. in this case,
First, a destination address (DA: Destination Address), then a source address (SA: Source Address), data type (Type), and finally, data (length 46 to 1500 bytes)
Is arranged. d is the format of the ATM cell,
The first five octets (bytes) are a logical path identifier (VPI: Virtual Path Identifier) and a logical channel identifier (VCI: Virtual Channel Identifier) as shown in the figure.
And a header including header error control (HEC: Header Error Check), followed by a 48 octet (byte) information field as a payload.

As shown in FIG.
In the form of M cells, the inside of the ATM switch and the ATM switch
The data is transferred between the AN connecting devices. The configuration of the embodiment of the inter-LAN connecting device shown in FIG. 4 will be described. 40 is an inter-LAN connecting device, 41 is a variety of cells (sources, destinations, etc. are different).
A separation unit that separates cells according to VPI / VCI in response to the input, a plurality of cell reception buffers 42 that store cells corresponding to VPI / VCI, and a conversion unit 43 that converts the header of the received cells according to the destination A header converting unit 44, a multiplexing unit 44 for multiplexing and transmitting a plurality of cells, a monitoring control unit 45 for monitoring received cells, a central control unit 46, an address conversion table 47, and a cell receiving buffer unit 48. , A header conversion table 49, and a VC path setting unit 50 that is driven when setting a downstream path with the inter-LAN connecting device that is the activation source.

Here, an operation when a transmission request for LAN data occurs in the configuration of FIG. 2 will be described. When a subscriber making a LAN data transmission request transmits data, A
A block of data having a format as shown in FIG.
(Switching network) The VPI and VCI assigned by the administrator are set in the cell header (see d in FIG. 3) and transferred to the ATM switch (at this time, the VCI of the header is transmitted from the LAN to the LA).
The VCI of the PVC logical channel to the N-to-N connection device is set to 0 because it is not used.)

The data transmitted from the LAN subscriber is LA
In the ATM exchange, each cell input from N is previously connected between the subscriber and the inter-LAN connecting device by PVC, so this information is transferred to the inter-LAN connecting device.

The operation of the inter-LAN connecting device shown in FIG. 4 will be described below with reference to the control flow shown in FIGS. S0 at the beginning of FIG.
This represents a state before the central control unit 46 of the interconnection device branches off in response to occurrence of a request from each unit or each event such as cell reception.

First, in the case of a control flow at the time of cell reception (processing after S5), which is a main function of the inter-LAN connecting apparatus, the central control unit 46 of the inter-LAN connecting apparatus 40 shown in FIG. This is determined in advance by the user, and which reception buffer is used by the LAN subscriber of each PVC when the inter-LAN connecting device is started up.

Therefore, the cells from the LAN subscriber are sequentially stored in the cell receiving buffer unit 42 assigned to the PVC included in the cell header in the separating unit 41,
At the same time, a copy (image) of the received cell is also input to the central control unit 46 by the operation of the read control unit 48 to assemble the subscriber information (S5 in FIG. 5). That is, a plurality of cells from the same subscriber are received, data (LAN data excluding the header) is formed in one block, and a destination address (DA in FIG. 3C) is detected from the data. The address conversion table 47 is searched using the address (S6 in FIG. 5).

The address conversion table 47 is shown in FIG. As shown in the configuration example in FIG. 1, each inter-LAN connecting apparatus has an address (displayed as a partner address) of a subordinate LAN (a LAN connected to this inter-LAN connecting apparatus by PVC) and a connection to the LAN. VPI / VCI (outgoing VP) representing a logical channel registered as a PVC
I, output VCI). The address conversion table 47 also stores information on VC (to be described later).

When the destination address of the received LAN data is detected from the address conversion table 47 (YES in S7 of FIG. 5), the VCI of the next received cell is 0. (Fig. 6
S8). This is to determine whether the received cell is received from the LAN or not (received from another inter-LAN connecting device or the like).

When VCI = 0, since the destination of this LAN data is the LAN under its own in S7,
The VPI / VCI of the pre-assigned PVC set in the address conversion table 47 is extracted and set in the header conversion table 49 (S14 in FIG. 6). At this time,
VCI is a LAN that the other party accommodates in the own LAN connection device.
Since it is a subscriber, it is set to 0. Subsequently, the read control unit 4
8 to sequentially read out the cells stored in the cell reception buffer unit 42 (S16).

The header conversion table 49 corresponds to B.1 in FIG. As shown in the configuration example, an output VPI and an output VCI are set for each VCI value (input VCI), and the header conversion unit 43 outputs the header of the cell read from the cell reception buffer unit 42. When the VCI matches the incoming VCI in the header conversion table 49, the VPI / VCI of the cell is converted into the corresponding outgoing VPI / outgoing VCI.

As a result, in the configuration of FIG. 4, the header of the read cell is converted by the header conversion unit 43 into the VPI (VPI to the LAN under the own LAN connection device) set in the header conversion table 49. After conversion, each cell is sent from the multiplexing unit 44 to the ATM exchange, and
Sent to N

Next, in S7 of FIG. 5, if it is determined that the address of the partner LAN is not stored in the address conversion table 47, the local LAN connection device stores the address of the partner LAN.
Since the AN subscriber is not accommodated, the cell is sent to the next adjacent LAN connection device.

That is, it is determined whether the input VCI is an inter-LAN connection address (S17 in FIG. 6). At this time, if the activation source LAN is accommodated in the own LAN connection device, VCI = 0, so that “NO” is determined. In this case, the own LA is added to the output VCI of the header conversion table 49.
An N-to-N connection device address is set, a VPI for the next inter-LAN connection device adjacent to the output VPI (the VPI of the PVC for the up path) is set (S18 in FIG. 6), and a request to read from the cell reception buffer is made (S16). Therefore, each cell holds the address of the inter-LAN connecting device accommodating the activation source LAN as the VCI value of the header and is sent to the next inter-LAN connecting device.

In steps S18 and S16, the activation source LAN
The cell transmitted from the inter-connecting device is input to the adjacent inter-LAN connecting device, and through the determinations of S5 to S7 in FIG.
If the subscriber is an AN subscriber, the processes of S8 and S14 in FIG. 6 are performed. If the user is not a LAN subscriber of the adjacent LAN connection device, the input VCI is set to LA in S17 of FIG.
It is determined that the address is an N-to-N connection device address (in the case of YES), and the process of S19 is performed to transfer this LAN data cell to a further adjacent inter-LAN connection device. That is, the VPI value of the next LAN connection device address is set in the header conversion table 49, and the VCI is
The process of setting the I (address of the inter-LAN connecting apparatus accommodating the starting LAN) is performed as it is, each cell is read from the reception buffer, the header is converted, and is transmitted to the next inter-LAN connecting apparatus.

Next, in S8 of FIG.
A case where it is determined that I is not 0 will be described. In this case, the LAN data transmitted from the inter-LAN connecting device accommodating the above-mentioned boot source LAN is transmitted to another inter-LAN connecting device accommodating the destination LAN (including a case where a relay inter-LAN connecting device is interposed). Occurs when received (other cases will be described later).

In this case, if it is determined that the VCI value is the address of the LAN-to-LAN connecting apparatus in the destination (to accommodate the boot destination LAN) LAN-to-LAN connecting apparatus (S9 in FIG. 6), then the ATM exchange is executed based on the VCI value. Then, a VC path setting procedure is executed and the process waits (S10, S11). In this process, since the cell is received via the up path by the inter-LAN connecting apparatus accommodating the destination LAN, the VCI (inter-LAN connecting apparatus address accommodating the activation source LAN) in the header of the received cell is extracted. The downstream path (the path from the destination inter-LAN connecting device to the starting inter-LAN connecting device) with the inter-LAN connecting device as a destination
This is requested by the C path call setting procedure.

When the destination LAN connection device receives the VPI / VCI of the VC determined by the search in the ATM exchange in response to the call setting request, the address conversion table 4
7, and the address of the request source is set as the destination address (S12 in FIG. 6). These partner addresses, VPI
The VCI is shown in FIG. V of the address conversion table shown in
It is set in the area for C (for the down path).

Next, an empty cell reception buffer unit 42 used by a cell having the corresponding VPI / VCI (downstream cell transmitted from the LAN of the subscriber to be activated) is allocated (S in FIG. 6).
13), the output VPI retrieved in the header conversion table 49
(V of the path by PVC that sends the upstream cell to the activated subscriber
PI) and VCI to 0 (S1 in FIG. 6).
4). Thereafter, S16 is executed and the cell reception buffer unit 4
2 is read out and transmitted to the boot destination LAN via the ATM exchange.

On the other hand, the inter-LAN connecting apparatus accommodating the boot destination LAN is operated by the boot destination LAN subscriber.
A reception buffer is allocated to receive cells using the VPI / VCI for downlink to the subscriber (not shown in FIG. 6).

In S15 of FIG. 6, the information of the backward direction (downstream) from the boot destination LAN to the boot source LAN is transmitted to the boot destination LA.
N is received by the inter-LAN connecting apparatus accommodating N, and is executed when it is determined in step 9 that the VCI is not the address of the inter-LAN connecting apparatus through steps S5 to S8 in FIGS. In this case, VCI = 0 between the LAN and the LAN-to-LAN connecting device by PVC, and the destination address of the downstream LAN data sets the output VPI and output VCI for the VC path stored in the header conversion table.

According to the setting of the header conversion table, the cell header of the LAN data in the reverse direction (downlink) from the LAN subscriber to be activated is converted into the VPI / VCI for the VC path and passed to the ATM exchange. As for the subsequent transfer information between the LAN connection devices, the PVC handles the upstream signal and the VC handles the downstream signal.

In S0 of FIG. 5, when the path connection request by the VC (S10 of FIG. 6) arrives at the other LAN connection device, the LAN connection device receives the VP.
An empty cell reception buffer used by the cell having the I / VCI is allocated (S3 in FIG. 5), and the monitoring control unit (45 in FIG. 4)
Request monitoring of the corresponding cell reception buffer (S in FIG. 5).
4).

In the state of S0 in FIG. 5, when a path disconnection request for the VC is generated from the ATM exchange, the corresponding VC VP is read from the address translation table (47 in FIG. 4).
The I / VCI information is deleted (S20 in FIG. 5).

Further, in S0 of FIG. 5, when a path disconnection request is issued from the monitoring control unit (45 in FIG. 4) in the inter-LAN connecting apparatus accommodating the LAN requesting the LAN service, the ATM exchange sets the VC path. A disconnection request is made (S1 in FIG. 5), and the corresponding VC is
Is deleted (S2 in FIG. 5).

The configuration and control operation of the monitoring control unit (45 in FIG. 4) that issues the disconnection request in S1 will be described. The monitoring control unit first receives the LA service from the subscriber,
The inter-N connecting device monitors traffic flowing using the VC path, and upon detecting no traffic for a certain period of time, issues a path disconnection request established by the inter-LAN connecting device accommodating the other party. Release the path in the ATM exchange. Upon receiving the release, the partner LAN connecting device deletes the information added in the corresponding address conversion table.

FIG. 8 is a diagram showing a related configuration of the monitoring control unit, and FIG. 9 shows a processing flow of the monitoring control. In FIG. 8, reference numeral 42 denotes a cell reception buffer unit, 45 denotes a monitoring control unit, 450 denotes a cell reception state management table, and 451 denotes a timing monitoring program.

In such a configuration, the monitoring control unit 45
In FIG. The control is performed as shown in FIG. When the cell using the buffer unit is received by the cell reception buffer unit 42 that receives the cell of the VC, “1” is set to the flag area (FLAG) at the corresponding position in the cell reception state management table 450 ( S1 in FIG. 9). Next, it is determined whether the “ACT” bit indicating the state of the table 450 is “1” (S2),
If it is not "1", "1" is set (S3), information (value used in VC) is set to the VPI / VCI at the corresponding position (S4), and the "timing monitoring program" Is activated (S5). Next, "1" is set to the flag bit of the table 450. (S6) The timing monitoring program is shown in FIG. As shown in (5), when the cycle is started in S5, a flag bit in which the ACT bit is set (state of "1") is obtained (S5).
7) If the flag bit is "0", since no cell has been received for a certain period of time, a request to disconnect the path using the corresponding VPI / VCI is issued (S9), and the process ends. If the flag bit is not "0" (S8), A
The flag at the position where the CT bit is set is set to "0" (S10), and the process ends.

[0054]

According to the present invention, a large amount of traffic is assumed in advance, the amount of the band for which PVC is set is set to half, and the downstream traffic can be managed by the band actually used. , Resources in the network can be used effectively. As a result, this amount can be allocated to other traffic. Further, since the VC path is established before the downstream information flows, the LAN connection service can be provided at a high speed in the same manner as the normal PVC connection between LANs.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a system configuration diagram in which the present invention is implemented.

FIG. 3 is a configuration diagram of LAN data and cells.

FIG. 4 is a configuration diagram of an embodiment of a LAN connection device.

FIG. 5 is a control flow (No. 1) in the LAN connection device.

FIG. 6 is a control flow (part 2) in the LAN connection apparatus;

FIG. 7 is a configuration diagram of each table.

FIG. 8 is a related configuration diagram of a monitoring control unit.

FIG. 9 shows a processing flow of monitoring control.

FIG. 10 is an explanatory diagram of a conventional example.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 activation source LAN 2 broadband network 3 inter-LAN connection device accommodating activation source LAN 4 inter-LAN connection device adjacent to inter-LAN connection device 3 5 inter-LAN connection device accommodating activation destination LAN 6 activation destination LAN

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 12/28 H04L 12/44-12/46 H04L 12/00-12/26 H04L 12/50-12/60

Claims (1)

(57) [Claims] 1. Between a plurality of LANs connected to a broadband switching network
Connection service of each LA connected to the broadband switching network.
N through the LAN connection device to which N belongs
Path between the LAN and the LAN connection device to which the LAN belongs
Is a LAN-to-LAN connection control method formed by a semi-permanent connection means (PVC) preset by a broadband exchange, wherein a subscriber of each LAN is connected to another LA via the broadband exchange network.
When traffic to the N subscribers occurs, the originating subscriber
Accommodating the start-up subscriber from the LAN connection device accommodating the
1 to 1 in the predetermined connection order
Uplink path via multiple LAN connection devices
Semi-fixed connection means (PV
C), the LAN-to-LAN connecting apparatus accommodating the call-in subscriber sets a downstream path to the LAN-to-LAN connecting apparatus accommodating the call-in subscriber on a broadband switching network by call-by-call. A LAN formed by connection means (VC), which monitors traffic on the set downstream path and releases the path when it detects no traffic for a predetermined time.
Connection control method .