JP2001186143A - Atm device, subscriber system, communication system, and data relay method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize the band of an ATM network to relay a communication channel of a terminal, needing a CBR service and a virtual communication channel of a CBR service by a VP/VC of the ATM network. SOLUTION: Upon the receipt of a setup message from a terminal 10, an ATM multiplexer 20 obtains a band of data from information in the setup message, sets the virtual communication channel of the CBR service by the VP/VC of the band, in response to this data band to an ATM network 30 to relay data between the communication channel and the virtual communication channel set between the terminal, in response to the setup message.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ATM (Asynchronou).
s Transfer Mode) The present invention relates to a technology for effectively utilizing the bandwidth of a network.

[0002]

2. Description of the Related Art Communication channels in non-ATM networks such as ISDN lines and VP (Virtual Path) / VC (Virtual Chane) in ATM networks.
ATM multiplexing devices such as ATM CLADs are known as devices for relaying with a virtual communication channel (connection) according to l).

In such a device, when a terminal connected to a communication channel is a terminal that requires a CBR (Constant Bit Rate) service of an ATM network, a PVC (Permanent Vir- tane) is used.
tual Connection), by VP / VC of the predetermined band
Always reserve a virtual communication channel for the CBR service,
For this terminal, the relay is generally performed using a virtual communication channel based on the VP / VC secured by the PVC.

[0004]

[0006] For a terminal requiring the CBR service of the ATM network, a fixed bandwidth V
According to the technology that always secures the virtual communication channel of the CBR service by P / VC, even if this terminal is not performing communication, the bandwidth of the virtual communication channel secured by PVC continues to be secured by the ATM network Therefore, this band is not effectively used. Further, even when the terminal performs communication in a band less than the band of the virtual communication channel, the band of the virtual communication channel secured by the PVC continues to be secured by the ATM network. It cannot be used, and the bandwidth utilization efficiency of the ATM network deteriorates.

Therefore, the present invention provides a relay between a communication channel of a terminal requiring a CBR service and a virtual communication channel of a CBR service by VP / VC of an ATM network so that the band of the ATM network can be effectively used. The task is to do this.

[0006]

In order to achieve the above object,
The present invention provides, for example, a non-ATM (Asynchronous Transfer Mod
e) Network communication channel and ATM network VP (Virtual Path)
CBR (ConstantBit Rate) by / VC (Virtual Chanel)
An ATM device for relaying data between a virtual communication channel of a service and a communication channel setting means for setting the communication channel for transmitting and receiving data, and a virtual channel setting means for setting the virtual communication channel by a CBR service And a relay unit for relaying the data between the set communication channel and the set virtual communication channel,
The communication channel setting unit sets the communication channel according to a call control message transmitted from the terminal, and the virtual communication channel setting unit sets the communication channel according to the band of the data on the set communication channel. An ATM device characterized by determining a band of the virtual channel.

According to such an ATM device, when setting a communication channel with a terminal, that is, when dialing up, an SVC (Switched Virtual Connection) for connecting a virtual communication channel by the CBR service is performed. ,
When the terminal does not perform communication, the bandwidth of the virtual communication channel by the CBR service can be released. Further, since the band of the virtual communication channel to be set is determined according to the band of the data on the set communication channel, only the band actually required for terminal communication is consumed.
It can be used as an M network resource.

Therefore, the bandwidth of the ATM network can be used more effectively than in the related art in which a fixed-band virtual communication channel using PVC is used irrespective of the presence / absence of communication of the terminal and the communication band.

[0009]

Embodiments of the present invention will be described below.

FIG. 1 shows a configuration of a communication system according to the present embodiment.

As shown in the figure, the communication system includes an ATM multiplexer 20 accommodating one or more terminals 10 and an ATM multiplexer 20.
It has a configuration connected to the network 30.

The interface between the ATM network 30 and the ATM multiplexer 20 is a user network interface according to the ATM network. On the other hand, the interface between the terminal 10 and the ATM multiplexer 20 is an ISDN user network interface,
Any interface such as a TCP / IP interface may be used.

In the following, this embodiment will be described by taking as an example the case where the interface between the terminal 10 and the ATM multiplexer 20 is an ISDN user network interface.

Next, FIG. 2 shows the configuration of the ATM multiplexer 20.

As shown, the ATM multiplexer 20 comprises a plurality of terminal interfaces 210 and an ATM interface 220.
, Main control unit 230, band determination table 231, ATM bus 2
Has forty. Also, each terminal interface 210
It has a cell processing unit 211, an ISDN line control unit 212, and an ISDN line interface unit 213.

Hereinafter, the operation of the ATM multiplexer 20 will be described from a terminal A connected to the ATM multiplexer A in FIG.
The case where a call is made to the terminal B connected to the TM multiplexer B will be described as an example.

FIG. 3 shows a communication sequence in this case.

In each of the messages shown in FIG.
The message between the ATM multiplexing device 20 and the ATM multiplexing device 20 is a call control message constituting a signaling procedure according to the ISDN user network interface, and the message between the ATM network 30 and the ATM multiplexing device 20 is the user network interface of the ATM network 30. Is a call control message that constitutes an SVC signaling procedure according to.

As shown in the figure, in this case, first, the terminal A
Dials up by transmitting a call setup message (SETUP) requesting a call to the terminal B to the ATM multiplexer A via the ISDN user network interface.

In response, the ISDN line interface unit 213 of the terminal interface 210 of the ATM multiplexer A transfers this call setup message to the ISDN line control unit 212. Upon receiving this, the ISDN line control unit 212 sends a call setting acceptance message (CALLPR) to the terminal A via the ISDN line interface unit 213.
OC). Further, ISDN line control section 212 passes the call setting message to main control section 230.

The main control unit 230 of the ATM multiplexer A analyzes the received call setup message, and requests the ATM network 30 for the VC / VP bandwidth based on the user speed and the information transfer capability as information in the call setup message. (Peak cell rate). Further, the service category of the VC / VP required for the ATM network 30 is determined.

Then, an ATM multiplexer B accommodating the terminal B is determined from the address information in the call setup message,
A call setup message (SET) requesting a VC / VP with the determined bandwidth in the determined service category with the multiplexer B
UP) is created and the ATM bus 240 and ATM
The data is transmitted to the ATM network 30 via the interface 220. At this time, the call setup message includes information in the call setup message received from the terminal, such as information transfer capability and user speed, in addition to the address information indicating the terminal B.

The ATM network 30 having received this transmits a call setting acceptance message (CALLPROC) to the ATM multiplexer A if the VP / VC according to the requested bandwidth can be set, and also sets the VP / VC to be set. A call setup message including the VCI / VPI of the ATM terminal B is sent to the ATM terminal B.

At the ATM terminal B, the call setup message received at the ATM interface 220 is transmitted to the ATM bus 240
Is sent to the main control unit 230 via Upon receiving this, the main control unit 230 matches the bandwidth requested by the call setup message from the ATM network 30 with the information transfer capability and user speed in the call setup message transmitted by the terminal A included in this call setup message. After confirming the integrity and confirming consistency, ATM
ATM network 30 via bus 240 and ATM interface 220
To the ISDN line control unit 212 of the terminal interface 210 accommodating the terminal B, analyzing the contents of the call setting message and detecting that the message is related to the terminal B. Convey a call setup message.

The ATM terminal B receives the ISDN
The line control unit 212 transmits a call setup message (SETUP) to the terminal B via the ISDN interface 213. And
After receiving the call setting acceptance message (CALLPROC) from the terminal B via the ISDN interface 213, if a call-in-progress message (ALERT) is received, this is transmitted to the main control unit 230. After that, when a call connection message (CONNECT) is received from the terminal B via the ISDN interface 213, a call connection acceptance message (CONNECT ACK) is transmitted to the terminal B via the ISDN interface 213, and the call is connected. The connection message (CONNECT) is transmitted to the main control unit 230.

In the ATM terminal device B, the main control unit 230
Call setting acceptance message (CALLPRO
After receiving C), if an alerting message (ALERT) is received, the alerting message (ALERT) is stored in the ATM network 30 via the ATM bus 240 and the ATM interface 220.
Send ATM cells. Thereafter, the ISDN line control unit 212
Via the ATM bus 240 and the ATM interface 220 upon receiving a call connection message (CONNECT) from
AT storing call connection message (CONNECT) in ATM network 30
Send M cell.

If the ATM network 30 receives a calling message (ALERT) after receiving the call setting acceptance message (CALLPROC) from the ATM multiplexer B, the ATM network 30 sends the calling message (ALERT) to the ATM multiplexer A. ) Is stored and the ATM cell is transmitted.
After that, when a call connection message (CONNECT) is received from the ATM multiplexer B, the ATM multiplexer A transmits
An ATM cell storing a call connection message (CONNECT) including the ATM terminal device A-side VPI / VCI of the VP / VC to be set is transmitted.

In the ATM multiplexer A, the call setting acceptance message, the ringing message and the call connection message received from the ATM network 30 are transmitted from the ATM interface 220 to the ATM multiplexer 220.
It is sent to the main control unit 230 via the bus 240.

In the ATM multiplexer A, the main control unit 230 which has received the calling message transmits the calling message to the ISDN line control unit 212 of the terminal interface 210 accommodating the terminal A.

The ATM multiplexer A receives the IS
The DN line control unit 212, via the ISDN interface 213,
Send a calling message (ALERT) to terminal A.

Further, in the ATM multiplexer A, the main control unit 230 receiving the call connection message transmits the call connection message to the ISDN line control unit 212 of the terminal interface 210 accommodating the terminal A, and ISDN line controller 212 received
Transmits a call connection message to terminal A via ISDN interface 213.

With the above procedure, the ISDN B channel between the terminal A and the ATM multiplexer A and the ISDN B between the terminal B and the ATM multiplexer B
B channel, VP / VC between ATM multiplexer A and ATM multiplexer B
Is established.

Therefore, the cell processing unit 211 of the terminal interface 210 of the ATM multiplexer A transmits the data received from the terminal A via the ISDN line interface 213 so that communication between the terminal A and the terminal B becomes possible. Is stored in the payload of the ATM cell to which the ATM terminal device A side VCI / VPI notified by the call connection message is added as a header, and A
ATM network 30 via TM bus 240 and ATM interface 220
Send to Conversely, the ATM interface 220 and
Via the ATM bus 240, the ATM terminal device A side VPI / VCI notified by the received call connection message is decellularized to extract data from the ATM cell added as a header, and the ISD
It transmits to terminal A via N line interface 213.
Similarly, the terminal interface 21 of the ATM multiplexer B
The cell processing unit 211 of 0 stores the data received from the terminal B via the ISDN line interface 213 in the payload of the ATM cell to which the ATM terminal device B side VCI / VPI notified by the call setup message is added as a header. Cell via ATM bus 240 and ATM interface 220.
It transmits to M network 30. Conversely, the ATM interface 220
And via the ATM bus 240, the ATM terminal device B side VPI / VCI notified by the received call setting message is decellularized to extract data from the ATM cell provided as a header, and the data is extracted via the ISDN line interface 213. To terminal B.

The ATM network 30 transmits the ATM cell provided with the ATM terminal device A side VCI / VPI to the ATM terminal device A and the ATM terminal device B side VCI / V
The ATM cell provided with the PI is relayed to the ATM terminal device B with the transmission quality according to the service category requested by the call setting message from the ATM multiplexing device A. However, ATM terminal device A
For both the side VCI / VPI and the ATM terminal B side VCI / VPI, the values of the VCI / VPI may be different between the transmitting side and the receiving side.

By the above operation, the communication channel by the ISDN B channel between the terminal A and the ATM multiplexer A, the communication channel by the VP / VC between the ATM multiplexer A and the ATM multiplexer B, the terminal B and the ATM A communication channel by the ISDN B channel is connected between the multiplexing devices B, and as a result,
With the communication channel established between A and terminal B, both terminals can communicate with each other.

When the desired communication is completed using the communication channel established between the terminals in this manner, the terminal A or the terminal B transmits the call by transmitting a call disconnection message (DISC). Disconnect.

When disconnecting the call from the terminal A, the terminal A first transmits a disconnection message to the ATM multiplexer A. Thereafter, in the same manner as the previous call setup message, the disconnection message is used as the release message, and the ATM network and the ATM multiplexer are used.
B and terminal B are transmitted. The ATM multiplexer A that has received the disconnection message returns a release message (RELEASE) to the transmission source of the disconnection message received by itself, and the terminal A, the ATM multiplexer A, the ATM network, and the AT that have received the release message.
The M multiplexing device B returns a release completion message (REL COMP) to the transmission source of the release message received by itself.

Thus, the ISDN between the terminal A and the ATM multiplexer A is
Communication channel by B channel, ATM multiplexer A and ATM
Communication channel by VP / VC between multiplexer B, terminal B and ATM
The communication channel of the ISDN B channel between the multiplexers B is disconnected and the ATM used for these communication channels is disconnected.
Resources on the network and ISDN user network interfaces are released. Therefore, these resources can be used for other communications.

The details of the operation performed by the main control unit 230 in the above operation to analyze the call setup message received from the terminal 10 via the terminal interface 210 and determine the bandwidth required for the ATM network 30 will be described below. explain.

The main control unit 230 basically transmits the call setup message to the band of the communication channel requested by the terminal 10.
ATM is the bandwidth determined by adding the bandwidth of the ATM cell header, etc.
It is determined as a band required for the network 30.

However, as described below, when the user speed and the information transfer capability satisfy predetermined conditions, a band corresponding to the user speed is determined as a band required for the ATM network 30.

FIG. 4 shows the contents of low layer compatibility, which is one of the information elements included in the call setup message. As shown in the figure, this information element describes information that can specify the transmission / reception rate of the terminal 10 as the user speed.

Therefore, as shown in FIG. 5, the correspondence between each user speed and the band determined for each user speed is described in advance in the band determination table 231. Main control unit 230
When the information transfer capability in the transmission capability information element in the received call setup message is unrestricted digital, the bandwidth corresponding to the user speed of the lower layer compatibility of the received call setup message is determined by the bandwidth determination table. A band obtained by adding the band for the ATM cell header and the like with reference to 231 is set as the band of the VP / VC requested to the ATM network 30.
As shown in the figure, in the present embodiment, when the information transfer capability is unrestricted digital, 8 Kbit / s, 16 Kbit / s,
Either 2 Kbit / s or 64 Kbit / s is selected according to the user speed, and a band obtained by adding a band corresponding to the ATM cell header to the selected band is set as a VP / VC band required for the ATM network 30.

On the other hand, if the information transfer capability in the transmission capability information element in the received call setup message is not unrestricted digital, for example, a voice call, the main control unit 230 determines a bandwidth of 64 Kbit / s. I do.

Here, the above-mentioned consistency check performed by the main control unit 240 means that the band requested by the call setting message from the ATM network 30 and the call setting message transmitted by the terminal included in the call setting message are included. This is to confirm the consistency between the information transfer capability of the user and the bandwidth determined as above from the user speed.

As described above, the information in the call setup message used for determining the bandwidth is not limited to the user speed of the lower layer compatibility, but may be any information as long as the information can specify the transmission / reception rate of the terminal 10. May be.

Hereinafter, the details of the operation performed by the main control unit 230 to determine the service category of the VC / VP required for the ATM network 30 in the above operation will be described.

In this embodiment, the terminal interface 210
For each call, the service category of the VC / VP requested for the terminal call accommodated by the terminal interface 210 is determined. For this purpose, a service category is set in advance in the ISDN line control unit 212 of each terminal interface 210, and this service category is also notified when the main control unit 230 notifies the call setting message. Main control unit 230
Makes the notified service category the service category of the requested VC / VP.

Here, the terminal 10 that needs the CBR service category, for example, the terminal interface 210 that accommodates a video conference terminal, etc., has a service category of CBR.
Set the service category. Thereby, for the call of this terminal 10, the VC / VP of the CBR service category is AT
It is requested and set in the M network 30. Where CBR
The service category VC / VP requests specifically include QoS,
This is done by CBR conformance definition based on traffic descriptor and CDVT.

It should be noted that in a system in which information that can specify the type of a higher layer such as higher layer compatibility can be sent from the terminal 10 to the ATM multiplexer 20 together with the call setup message, the ATM multiplexer 20 The service category of the VC / VP required for the call of the terminal may be determined.

Next, the details of the ATM cell conversion and decellulation performed by the cell processing unit 211 of the terminal interface 210 will be described.

FIG. 6 shows the configuration of the cell processing unit 211.

As shown in the figure, the cell processing unit 211 includes a time slot extraction unit 601, a sub-rate extraction unit 602, and a cell conversion unit 603 as a configuration for performing cell conversion. Also, as a configuration for performing deceleration, it includes a deceleration unit 604, a sub-rate distribution unit 605, and a time slot distribution unit 606.

Now, the operation of the cell processing unit 211 will be described by taking as an example a case where the communication channel requested by the terminal 10 in the call setting message is the 1B channel.

In this case, transmission and reception between the terminal 10 and the ATM multiplexer 20 are performed at a rate of 64 Kbit / s. Therefore, the user speed is 8 Kbit / s, 16 Kbit shown in FIG.
In a call in which a user rate of 32 Kbit / s or 32 Kbit / s is specified as a call connection message, a part of 64 Kbit / s (8 Kbit / s, 16 Kb) actually used for transmitting and receiving significant data is used.
it / s, 32 Kbit / s) and the rest are not used.

FIG. 7 shows this situation.

FIG. 7 (a) shows the bit position of one B channel in the layer 1 frame on the ISDN user network interface.
One octet (8 bits) is transmitted / received in (TS0) and time slot 1 (TS1). Therefore, if two octets (16 bits) of information are transmitted / received per frame for each B channel and significant information is set to all bits of two octets, the rate of significant information is 64.
Kbit / s.

Next, FIGS. 7 (b) to 7 (d) show 8
The user bit rates of Kbit / s, 16 Kbit / s, and 32 Kbit / s indicate bit positions to which significant information is transmitted in a call specified as a call connection message.

As shown, 8 Kbit / s, 16 Kbit / s,
In a call in which a user speed of 32 Kbit / s is specified as a call connection message, significant information is set only in some bits of each time slot (8 bits), and dummy bits are set as the remaining bits are empty. Then 1B channel 6
Only some rates of 4Kbit / s are used.
Specifically, in the case of 8 Kbit / s, bit 7 of each time slot
Only for 16Kbit / s, each time slot bit
7 and 6 only, 32 Kbit / s
Only bits 7, 6, 5, and 4 are used for transmitting and receiving significant information.

Therefore, in the present embodiment, each ATM multiplexer 20 transmits only a significant information portion of the information transmitted / received on the B channel to / from the terminal 10 between the ATM multiplexers 20.
By transmitting and receiving via the network 30, the band of the ATM network 30 is effectively used.

That is, in the cell conversion, first, the time slot extracting section 601 extracts the data of the target B channel time slot from each frame. Next, the sub-rate extraction unit 602 extracts bits in which significant information is set from the extracted data of the time slot. Here, when the bandwidth determined by the main control unit 230 from the user speed is 8 Kbit / s, the bit of each time slot is
7 for 16Kbit / s, bit 7 for each time slot,
6 for 32 Kbit / s, bit 7 for each time slot,
6, 5, 4 and 64Kbit / s
In the case of, bits 7, 6, 5, 4, 3,
Extract 2, 1, 0.

Next, the sub-rate extraction unit 6
A payload, which stores the bits extracted by 02 and is structured in a format compatible with the structured data transfer protocol of AAL1, is created, and an ATM header is added thereto to form an ATM cell.

Here, the creation of the payload is performed as follows.

First, the user area information is shown in FIG.
Create as shown in (c).

That is, when the band determined by the main control unit 230 from the user speed is 8 Kbit / s, 2 bits obtained by arranging 1 bit extracted from each time slot in time slot order are arranged in frame order, and user area information and I do. Also,
The band determined by the main control unit 230 based on the user speed is 16 Kbit /
In the case of s, 4 bits obtained by arranging 2 bits extracted from each time slot in the order of the time slot are arranged in the frame order and used as user area information. When the band determined by the main control unit 230 based on the user speed is 64 Kbit / s, 8 bits in which 4 bits extracted from each time slot are arranged in the time slot order are arranged in the frame order and used as user area information.
Although illustration is omitted, when the bandwidth determined by the main control unit 230 based on the user speed is 64 Kbit / s, 16 bits in which 8 bits extracted from each time slot are arranged in the order of the time slot are used in the same manner as in the related art. Arrange them as user area information.

Next, of the 48 octets of the payload of each ATM cell, the remaining 47 octets excluding the sequence number 1 octet and the pointer 1 octet for every 8 ATM cells required as a format conforming to the structured data transfer protocol of AAL1 are removed. Alternatively, the user area information is sequentially stored in 46 octets. Information indicating the positional relationship between time slot 0 and time slot 1 in the payload is stored in the pointer for each 8 ATM cell.

Next, in the deceleration, the reverse process is performed to restore a stream of 1 k channel 64 kbit / s and transmit it to the terminal 10.

That is, the decelerating section 604 extracts user area information, and extracts bits or bit strings in time slot order from the user area information in frame order according to the band determined by the main control section 230 from the user speed. I do. Then, the sub-rate distribution unit 605 adds dummy bits to the extracted bits or bit strings for each time slot to generate data for each 1-octet time slot. And finally, the time slot distribution unit 606
Via the N-line interface 213, the data of each time slot of each octet frame, the data of the time slot 0 whose position in the user area information is the data of the time slot 0 of the target B channel frame Then, the data of the time slot 1 whose position in the user area information is transmitted to the terminal 10 as the data of the time slot 1 of the frame of the target B channel.

The embodiment of the present invention has been described above.

In the above embodiment, the ATM multiplexing apparatus 20 determines the VP / VC band from the information included in the call setup message, but the terminal 10 has a certain rate (8, 16, 32, 64 Kbit / s). s), it is known in advance that the bandwidth determination table of the ATM multiplexer 20 stores the terminal interface 210 accommodating the terminal 10 and the bandwidth (8, 16) corresponding to the rate. , 32, 64 Kbit / s) may be fixedly set, and the VP / VC band used for each call of the terminal 10 may be determined according to the correspondence.

In this case, in the ATM multiplexer 20 on the receiving side, the bandwidth indicated by the call setting message and the bandwidth corresponding to the terminal interface 210 accommodating the receiving terminal 10 set in the bandwidth determination table of the terminal. May be performed as the consistency check.

[0072]

As described above, according to the present invention, the communication channel of the terminal requiring the CBR service and the VP /
The relay between the VC and the virtual communication channel of the CBR service can be performed so that the band of the ATM network can be used effectively.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of an ATM multiplexer according to an embodiment of the present invention.

FIG. 3 is a diagram showing a communication sequence in the communication system according to the embodiment of the present invention.

FIG. 4 is a diagram showing lower layer consistency information.

FIG. 5 is a diagram showing contents of a band determination table according to the embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a cell processing unit according to the embodiment of the present invention.

FIG. 7 is a diagram showing a user information bit position at an intermediate speed.

FIG. 8 is a diagram showing user area information obtained by structuring user information at an intermediate speed according to the embodiment of the present invention.

[Explanation of symbols]

 10 terminal 20 ATM multiplexer 30 ATM network 210 multiple terminal interfaces 211 cell processing unit 212 ISDN line control unit 213 ISDN line interface unit 220 ATM interface 230 main control unit 231 bandwidth determination table 240 ATM bus 601 Time slot extractor 602 Subrate extractor 603 Cell generator 604 Decellularizer 605 Subrate distributor 606 Time slot distributor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K030 GA08 HB00 HC01 HC04 HD01 JA01 JA06 KA14 LB01 LC09 LE06 5K033 AA01 BA05 CB06 CC01 DA05 DA15 DB17 DB18 5K051 AA05 CC02 CC04 DD09 FF12 GG02 HH12 JJ03 JJ09 JJ12

Claims (6)

[Claims] A communication channel for a non-ATM (Asynchronous Transfer Mode) network between one or a plurality of terminals and a VP (Virtual Path) / VC (Vi) of an ATM network.
ATM that relays data to and from the virtual communication channel of CBR (Constant Bit Rate) service using rtualChanel)
A communication channel setting means for setting the communication channel for transmitting and receiving data; a virtual channel setting means for setting the virtual communication channel according to a CBR service; and a communication channel between the set communication channel and the set virtual communication channel. Relay means for relaying the data, wherein the communication channel setting means sets the communication channel in accordance with a call control message transmitted from the terminal; and An ATM device, wherein a band of the virtual channel to be set is determined according to a band of the data on a channel. 2. The ATM device according to claim 1, wherein the virtual communication channel setting means sets the virtual communication channel according to a data band indicated by information included in a call control message transmitted from the terminal. An ATM device for determining a channel band. 3. The ATM device according to claim 2, wherein the data band indicated by the information included in the call control message transmitted from the terminal is included in a bit stream transmitted / received on the communication channel. The virtual communication channel setting means sets a virtual communication channel of a band corresponding to a band in which significant data is transmitted and received on the communication channel, according to the band of the significant data. The ATM device, wherein the band of the significant data includes a band less than a band of a bit stream transmitted / received on the communication channel. 4. The ATM device according to claim 1, 2 or 3,
AT comprising the one or more terminals
M network subscriber system. 5. The subscriber system according to claim 4, wherein:
A communication system comprising the ATM network. 6. A communication channel for accommodating one or a plurality of terminals and a non-ATM (Asynchronous Transfer Mode) network between the accommodated terminals and a VP (Virtual Path) / VC (Vi) of the ATM network.
A method of relaying data between a virtual communication channel of a CBR (Constant Bit Rate) service using a virtual channel and a communication channel setting step of setting the communication channel for transmitting and receiving data; A virtual channel setting step of setting a channel; and a relaying step of relaying the data between the set communication channel and the set virtual communication channel. The communication channel setting step includes a step of: The communication channel is set according to a control message, and the virtual communication channel setting step determines a band of the virtual channel to be set according to a band of the data on the set communication channel. Relay method.