JP2000269987A - Atm subscriber device and its band-managing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To flexibly assign band for the data transmission of a subscriber terminal by receiving an applied band value from the subscriber terminal, deciding whether or not the declared band is allowed, and transmitting a signal received from the subscriber terminal to a station side according to the declared band value when the declared band value is allowed. SOLUTION: When one subscriber newly requests a network management part 34 to increase an incoming band, a network management part 34 receives this request value and passes it to a band management part 27. The band management part 27 decides whether or not this request value is accepted. When it cannot be accepted, this is reported to the subscriber via the network management part 34 and the processing returns to the start. When the request value is acceptable, the band management part 27 informs the network management part 34 of the check result, and then the network management part 34 informs even the requesting subscriber of the result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ATM subscriber device in an ATM network system and a band management method thereof, and more particularly, to an ATM subscriber device applicable to a video on demand (VOD) system and a band management method thereof.

[0002]

2. Description of the Related Art In a video-on-demand system using an ATM transmission line, a signal from a remote video server or the like is transmitted to an AT at a subscriber's house via the ATM transmission line.
Sent to the M subscriber unit, the ATM subscriber unit transmits its signal to each user's set top box (STB) via coaxial or paired wires. Also, request signals and control signals for programs and the like are transmitted from each set-top box to the ATM.
The signals are sent to the subscriber unit, and the signals are transmitted from the ATM subscriber unit to the video server side.

FIG. 1 is a diagram showing a configuration example of a main part of a conventional ATM subscriber device 20. As shown in FIG. As shown in FIG.
The subscriber device 20 includes subscriber interface units 1 to 1
6, a cell bus 17, and a polling access unit 18. Each subscriber interface unit is connected to the set top box 19. Analog data from each set-top box is sent to the subscriber interfaces 1 to 16 via coaxial or pair wires, and the data is converted into cells by the subscriber interfaces 1 to 16. Next, the polling access unit 18 communicates via the cell bus 17 sharing a plurality of subscriber interface units.
Each of the subscriber interface units 1 to 16 is sequentially polled with the address assigned to each subscriber. The cell is transmitted from the polling access unit 18 to the station side by the polling.

[0004]

In a video-on-demand system, not only a request signal and a control signal but also a large amount of data such as an image is required as data transmitted from a subscriber. Also, ATM subscriber devices are required to be low cost. However, in the above-mentioned conventional ATM subscriber device, the polling cycle to each subscriber interface unit is fixed, so that the band of data that the subscriber terminal can transmit via the set-top box is fixed. That is, the band is uniformly and fixedly allocated to a plurality of subscriber terminals that can be accommodated by the ATM subscriber device within a range of resources allocated to the ATM subscriber device from the station side. Therefore, for example, even if a certain subscriber terminal is in a dormant state, its resources cannot be utilized, so that there is a problem that the bandwidth may be insufficient for transmitting the above-mentioned large-capacity data. . In addition, in order to realize effective use of resources by the conventional technology, for example, it is necessary to use an expensive chip for UPC processing having functions such as smoothing, cell discarding, and addition of a violation tag. In this case, ATM subscriber equipment cannot be provided at low cost.

The present invention has been made in view of the above points, and provides an ATM subscriber apparatus capable of flexibly allocating a bandwidth for data transmission of a subscriber terminal and a bandwidth management method thereof. With the goal.

[0006]

To achieve the above object, the present invention is configured as follows. The present invention provides an ATM
An ATM subscriber device in a network system, the total bandwidth value being the sum of a maximum allowable bandwidth value of a signal transmitted from a subscriber terminal accommodated in the ATM subscriber device and a bandwidth value set for each subscriber terminal. Means for receiving the declared bandwidth value declared from a certain subscriber terminal, and determining whether or not to permit the declared bandwidth value using the maximum allowable bandwidth value and the total bandwidth value. Means for transmitting a signal received from the subscriber terminal to the station according to the declared bandwidth value when the declared bandwidth value is permitted.

According to the present invention, the bandwidth value declared by the subscriber is accepted according to the maximum allowable bandwidth value, and the bandwidth value is assigned to the subscriber, so that the bandwidth of each subscriber is fixed as in the prior art. And the bandwidth can be flexibly allocated to the subscriber. Therefore, a specific subscriber can transmit a large amount of data. In the above configuration, the determination unit may include a unit that compares a value obtained by subtracting the total bandwidth value from the maximum allowable bandwidth value with the application bandwidth value.

[0008] According to this, it is clear how much margin the bandwidth of the ATM subscriber device has, and it is possible to make an accurate determination. Further, in the above configuration, the transmitting means includes means for transmitting a signal received from the subscriber terminal to the station based on a polling signal, and means for issuing the polling signal at a timing according to the declared band value. May be included.

According to the present invention, the band allocation can be changed only by changing the timing of the polling signal, and an ATM subscriber apparatus can be provided without using an expensive chip. In the above configuration, the declared bandwidth value is transmitted to the ATM subscriber device via a network management unit that relays the declared bandwidth value from each subscriber terminal, and the declaration is accepted via the network management unit. May be notified to the subscriber terminal.

According to the present invention, the network management unit relays the declared bandwidth value, so that the network management unit can handle the declared bandwidth values of a plurality of ATM subscriber devices, and the effect of cost reduction is achieved. is there. Further, in the above configuration, the ATM subscriber device includes a means for counting the number of ATM cells passing within a predetermined period;
Means for comparing the number of TM cells with a number based on a predetermined band value, and, if the number of ATM cells is larger than the number based on the predetermined band value, changing a route of a received ATM cell. Means.

According to the present invention, an ATM cell exceeding a predetermined band value is sent to another path.
Processing for TM cells can be performed efficiently.
For example, processing such as discarding, smoothing, and adding a violation tag can be performed on the ATM cell. Further, in order to achieve the above object, the present invention may be configured as follows.

The present invention relates to a band management method for an ATM subscriber unit in an ATM network system, which includes a maximum allowable band value of a signal transmitted from a subscriber terminal accommodated in the ATM subscriber unit, Holding the total bandwidth value obtained by summing the bandwidth values set for the subscriber terminals, receiving the declared bandwidth value declared from a certain subscriber terminal, and performing the application using the maximum allowable bandwidth value and the total bandwidth value. A determining step of determining whether or not to permit a bandwidth value; anda transmitting step of transmitting a signal received from the subscriber terminal to the station according to the declared bandwidth value when the declared bandwidth value is permitted. Having.

[0013] The determining step may include a step of comparing a value obtained by subtracting the total bandwidth value from the maximum allowable bandwidth value with the applied bandwidth value. The transmitting means may include a step of issuing a polling signal at a timing according to the declared bandwidth value, and a step of transmitting a signal received from the subscriber terminal to the station based on the polling signal. Is also good.

[0014] In the above configuration, a step of transmitting a declared bandwidth value from the subscriber terminal to the ATM subscriber device by a network management unit relaying a declared bandwidth value from each subscriber terminal; Receiving from the ATM subscriber device that the declaration has been accepted, and transmitting the received notification to the subscriber terminal.

Further, in the above configuration, a step of counting the number of ATM cells passing within a predetermined period, a step of comparing the number of ATM cells with a number based on a predetermined band value, If the number is larger than the number based on the predetermined band value, the step of changing the route of the received ATM cell may be included. According to these inventions, the same operation and effect as those described above can be obtained.

[0016]

FIG. 2 is a block diagram of an ATM subscriber unit 21 according to an embodiment of the present invention. An outline of an embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the ATM subscriber unit 21 has a plurality of subscriber interface units 23, a band management unit 27, a polling access unit 29, and a cell bus 31 shared by each unit. Further, a subscriber terminating unit 32 corresponding to a set-top box and a network management unit 34 for performing processing of a band application from the subscriber terminal 33 are connected to the ATM subscriber unit 21, and a polling access unit 29 is connected to the station side device. Is connected to the line.

The subscriber interface unit 23 has a cell flow detection unit 25, a subscriber connection unit 46, a cell transmission unit 48, a route selection unit 50, a cell bus interface unit 52, and a violated cell processing unit 54. The unit 25 is the comparison unit 3
6 and a cell counter section 38. Further, the bandwidth management unit 27 includes a polling control unit 40, a bandwidth determination setting unit 42, and a bandwidth flow rate conversion unit 44.

This configuration is a configuration in which a cell flow detection unit 25 and a band management unit 27 are added to a conventional ATM subscriber device. Next, an outline of the operation of the ATM subscriber device 21 will be described. The subscriber connection unit 46 A / D converts analog data transmitted from the subscriber termination unit 32 via a coaxial or twisted pair line, and passes the converted data to the cell transmission unit 48. The cell transmitting unit 48 performs cell identification of the data from the subscriber connecting unit 46, and sends the data to the cell bus interface unit 52 or the violating cell processing unit 54 via the route selecting unit 50 by a UTOPIA interface or the like. In addition, the cell transmission unit 48 sends the cell flow detection unit 25 a
A signal for identifying cells such as SOC and SCAV is transmitted. The route selecting unit 50 and the violating cell processing unit 54 will be described later.

The cell stream sent by the cell transmitting section 48 is judged by the cell flow detecting section 25 as to whether the cell stream does not violate a band previously applied and permitted by the subscriber. In the case of a violation, the cell flow detection unit 25 sends a control signal for sending the violating cell to the violating cell processing unit 54 to the route selection unit. If not violated, the cell flow detecting unit 25 sends a control signal for sending the normal cell to the cell bus interface unit 52 to the route selecting unit 50.

The cell transmitted to the cell bus interface unit 52 is determined by the polling signal from the polling access unit 29 which subscriber's cell is to be transmitted to the cell bus 31. The subscriber's cell specified by the polling signal is It is sent to the cell bus 31. That is, in the polling access unit 29, a unique address is assigned to each subscriber, and these addresses are periodically assigned to the cell bus 31.
The cell bus interface unit 52 transmits a cell to the cell bus 31 when the address of the cell bus interface unit 52 matches the address from the polling access unit 29. By changing the address generation cycle for each subscriber, the allowable bandwidth of each subscriber can be changed. Subsequently, the cell flow rate detection unit 25
The outline of the operation related to the bandwidth management unit 27 will be described.

Cell counter 3 in cell flow detector 25
8 counts the number of cells from the subscriber terminal 33 received via the subscriber connection unit 46 and the cell transmission unit 48 for a certain period, and passes the count value to the comparison unit 36. Next, the comparing section 36 compares the count value from the cell counter section 38 with the count value stored in the band flow rate converting section 44 in the band managing section 27 described later in detail. The count value from the band flow rate conversion unit 44 is a count value according to the band that the subscriber terminal is permitted to use. As a result of the comparison,
Information indicating whether or not the count value from the cell counter unit 38 has exceeded the count value stored in the bandwidth flow rate conversion unit 44 is passed to the route selection unit 50.

The route selection unit 50 selects a route based on the signal transmitted from the comparison unit 36. That is, as described above, when the bandwidth of the data from the subscriber terminal 33 exceeds the permitted bandwidth, it is determined that the violation has occurred, and the cells after the excess are passed to the violating cell unit 54 as violation cells.
On the other hand, when the band of the data from the subscriber terminal does not exceed the permitted band, it is determined to be normal, and the cell is passed to the cell bus interface unit 52 as a normal cell.

The violating cell processing unit 54 can perform three types of processing, such as cell discarding, smoothing for transmission with a delayed time, and addition of a violation tag, and an optimum one can be selected depending on the system configuration. Here, the subscriber's requested bandwidth value is transmitted to the bandwidth / flow rate conversion unit 44 in the bandwidth management unit 27 via the network management unit 34, and the bandwidth / flow rate conversion unit 44 determines the applied bandwidth value in advance according to the bandwidth. It is converted to a cell count value within a predetermined period.

The generation cycle of the address transmitted from the polling access unit 29 to the cell bus interface unit 52 is set by the band management unit 27 according to the subscriber's band application. Next, the main part and main processing of the ATM subscriber device will be described in detail. FIG. 3 is a flowchart showing a process from when a bandwidth increase is performed after a certain subscriber requests a bandwidth increase. This processing will be described with reference to FIG.

In step 1, a certain subscriber newly requests the network management unit 34 to increase the upstream bandwidth. In step 2, the network management unit 34 receives this request value and passes it to the band management unit 27. In step 3, the bandwidth management unit 27 determines whether the request value is accepted. This is done by checking if the ATM subscriber device tolerance is exceeded or not exceeded.

If the result of the determination is that it is not accepted, this is notified to the subscriber via the network management unit 34 in step 4 and the process returns to the beginning. If accepted, as step 5, the bandwidth management unit 27 notifies the network management unit 34 of the check result, and then the network management unit 34 notifies the requesting subscriber of the result.

Subsequently, in step 6, the bandwidth management unit 2
7 updates the band register in the band management unit described later and changes the generation cycle information of the polling signal, and passes this cycle information to the polling access unit 29. As step 7,
The polling access unit 29 reads cells on the cell bus 31 by transmitting a polling signal to all subscribers connected to the cell bus 31. At this time, the generation cycle of the polling signal becomes more frequent for the subscriber who has requested the band increase.

FIG. 4 is a diagram for explaining polling from the polling access unit 56 to the subscriber interface units # 1 to #n. (A) shows the configuration, and (b) is a time chart. As shown in (b), the polling access unit 56 periodically sends a strobe signal to the subscriber interface units # 1 to #n. here,
When the strobe signal # 1 is output, the cell of the subscriber # 1 is output from the cell bus interface unit 60 to the cell bus, and is taken into the polling access unit 56. #
The same applies to 2 to #n. By changing the cycle of the strobe signal for each subscriber, it is possible to flexibly use the band.

FIG. 5 is a flow chart showing a process of determining the acceptance of a request value of an application among the procedures of the band management process. The processing at the time of determination will be described with reference to FIG. First, as a step 11, it is checked whether or not the current total value of the used bands of the subscribers # 1 to #N is larger than the allowable value of the ATM subscriber device. Here, if it exceeds the allowable value, an alarm process is executed as step 12.

If not, step 13
It is checked whether a certain subscriber #n has newly applied for a band, and if there is no application, the process returns to the beginning. If there is an application, as step 14, the total is recalculated according to the declared value. Next, at step 15, it is checked whether the value exceeds the allowable value. If it exceeds, an error message indicating that the allowable value has been exceeded is returned to the subscriber who applied as a step 16. If not, step 17
To update the current total.

FIG. 6 shows a band judgment setting unit 42 and a band flow rate conversion unit 44 when a subscriber newly applies for a band.
It is a figure which shows operation | movement. (A), (b), (c) of FIG.
As shown in (1), the band determination setting unit 42 includes three registers, a maximum value storage register, a current value storage register, and a margin value storage register. The maximum value storage register stores the maximum value obtained by summing the maximum usable bandwidths of the subscribers # 1 to #N, and the value corresponds to the allowable value in the flowchart shown in FIG. The current value storage register stores the total value of the currently used bandwidth, and the value corresponds to the current total value in the flowchart shown in FIG. The margin value storage register stores a value obtained by subtracting the value of the current value storage register from the value of the maximum value storage register, and the value is a value indicating how much the bandwidth can be increased in the future.

Further, as shown in (x) and (y), the bandwidth flow rate conversion unit 44 has an application bandwidth register and an application conversion value register. The applied bandwidth register has an area for storing a current applied bandwidth value and a newly applied bandwidth value for each subscriber. The application conversion value register stores a value obtained by converting the value of the application band register into a digital value that is easily calculated in a circuit.

As shown in the figure, when there is an application from the subscriber in step 20, the value is stored in the new application value area of the corresponding subscriber area in the application bandwidth register. Next, as shown in step 21, the stored value is converted into a digital value that can be easily calculated in a circuit, and stored in a corresponding area of the application conversion value register. Subsequently, as shown in step 22, the new application value is compared with the margin value stored in the margin value storage register. Here, if the new application value is smaller than the margin value, the new application value is accepted, and as shown in step 23, the current values of the application bandwidth register and the application conversion value register are updated.
The polling access unit 29 performs polling based on the updated value.

FIG. 7 is a diagram showing the ATM subscriber unit of the present invention more specifically. 2, a BAS (broadband access shelf) corresponds to the ATM subscriber device in FIG. As shown in the figure, the polling access unit 29 is incorporated in the optical multiplexing conversion unit 62, and the band management unit 27 is incorporated in the monitoring control unit 64. In addition, a plurality of BASs (BAS # 1 to BAS #
n) Providing is performed.

FIG. 8 is a diagram showing the overall configuration of a video-on-demand system using the ATM subscriber device of the present invention. In the video-on-demand system shown in the figure, the digital server 66 transmits the video to the subscriber and
The G encoder 68 transmits the live broadcast program to the subscriber.
Subscribers can set STB (Set Top Box)
70, the digital server 66 or MPE
The G encoder 68 transmits the video.

The transmitted video data is transmitted to the exchange 72 or A
The information from the server is terminated by a BFS (feeder shelf) 80 through a TM MUX 74 and a trunk transmission line composed of ADM devices (76, 78). And from BFS80 to BTS (Tributary Shelf)
Information is distributed to 82. In this example, BTS
Can connect up to 10 units. Also, BFS and B
The distance of the TS is within 20 m.

Information is distributed from the BTS to the BAS 84, which is the ATM subscriber device of the present invention. In this example, BT
A maximum of 12 units of BAS can be connected to S. There is a transmission path directly from the BAS to the STB, and up to 16 STBs can be connected to one BAS unit. In the example shown here, the BAS 84 distributes the downstream video signal to the subscriber at 51 Mbps. A request signal and a control signal are transmitted from the STB 70 to the BAS. Further, according to the present invention, the transmission band from the STB can be flexibly set, so that a large amount of data such as a moving image can be transmitted from a certain STB.

The present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention. For example, the bandwidth management method of the present invention can be applied to an ATM switch.

[0039]

As described above, according to the present invention, the resource band allocated to the ATM subscriber unit from the station side can be flexibly allocated to the subscriber, so that the band can be used effectively. Becomes possible. That is, in the conventional technology, the bandwidth of the subscriber is fixedly determined by the value set in the system, so that the bandwidth is redistributed when the subscriber is added, or the subscriber temporarily provides a service of a bandwidth higher than the current level. However, according to the present invention, each subscriber applies for a band to be used, determines whether or not the ATM subscriber system can provide a band in real time, and provides a band. It is possible to easily redistribute the band when the number of subscribers is increased and to temporarily receive the service of the band higher than the present state.

Further, since the present invention can be realized without using expensive chips and the like, it is possible to provide an ATM subscriber device with improved functions at low cost. Furthermore,
Since the bandwidth of the subscriber can be changed flexibly and efficiently, the present invention is extremely effective in widening the bandwidth of data transmission from the subscriber who is expected to have a future demand due to a new service or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an ATM subscriber device according to the related art.

FIG. 2 is a block diagram of an ATM subscriber device according to the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a process for a request for a bandwidth increase.

FIG. 4 is a diagram illustrating polling from a polling access unit.

FIG. 5 is a flowchart illustrating a determination process for a request to increase the bandwidth.

FIG. 6 is a diagram illustrating an operation of band management in a band management unit.

FIG. 7 is a diagram specifically showing an ATM subscriber device according to the embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a video-on-demand system using an ATM subscriber device according to an embodiment of the present invention.

[Explanation of symbols]

 1-16, 58 Subscriber line interface 18, 29, 56 Polling access unit 19 Set-top box 20 ATM subscriber unit 23 Subscriber line interface unit 25 Cell flow detection unit 27 Band management unit 31 Cell bus 32 Subscriber termination unit 33 Subscriber terminal 34 network management unit 36 comparison unit 38 cell counter unit 40 polling control unit 42 bandwidth judgment setting unit 44 bandwidth flow rate conversion unit 46 subscriber connection unit 48 cell transmission unit 50 route selection unit 52, 60 cell bus interface unit 54 violation Cell processing unit 62 Optical multiplex conversion unit 64 Supervisory control unit 66 Digital server 68 MPEG2 encoder 70 STB (set-top box) 72 Switching unit 74 ATM MUX 76, 78 ADM unit 80 BFS (feeder shelf) 82 BTS ( Li tributary shelf) 84 BAS (broadband access shelf)

Continued on the front page F term (reference) 5C064 BA01 BA07 BB05 BC10 BC16 BC18 BC20 BC27 BD01 BD02 BD07 BD09 5K030 GA08 GA11 HA10 JA08 JL08 KA05 KA11 KA13 LB02 LC06 LC08 LD17 9A001 CC04 DD10 JJ18 JJ20

Claims (10)

[Claims] 1. A in an ATM network system
A TM subscriber unit, which holds a maximum allowable band value of a signal transmitted from a subscriber accommodated in the ATM subscriber unit and a total band value obtained by summing a set band value for each subscriber terminal. Means, means for receiving a declared bandwidth value declared from a certain subscriber terminal, determining means for determining whether to permit the declared bandwidth value using the maximum allowable bandwidth value and the total bandwidth value, An ATM subscriber device, comprising: transmitting means for transmitting a signal received from the subscriber terminal to a station according to the declared bandwidth value when the declared bandwidth value is permitted. 2. The ATM subscriber device according to claim 1, wherein said determination means includes means for comparing a value obtained by subtracting said total bandwidth value from said maximum allowable bandwidth value with said declared bandwidth value. 3. The transmitting means comprises: means for transmitting a signal received from the subscriber terminal to a station based on a polling signal; and means for issuing the polling signal at a timing corresponding to the declared bandwidth value. The ATM subscriber device according to claim 1, comprising: 4. The said report bandwidth value is transmitted to said A through a network management unit which relays the report bandwidth value from each subscriber terminal.
The ATM subscriber device according to claim 1, which is transmitted to the TM subscriber device and notifies the subscriber terminal that the declaration has been accepted via the network management unit. 5. A means for counting the number of ATM cells passing within a predetermined period, a means for comparing the number of ATM cells with a number based on a predetermined band value, and wherein the number of ATM cells is Means for changing a route of a received ATM cell when the number is larger than a number based on a predetermined band value. 6. A in an ATM network system
A bandwidth management method for a TM subscriber device, comprising: a total bandwidth value obtained by adding a maximum allowable bandwidth value of a signal transmitted from a subscriber side accommodated in the ATM subscriber device and a bandwidth value set for each subscriber terminal. Holding a declared bandwidth value from a certain subscriber terminal; and determining whether to permit the applied bandwidth value using the maximum allowable bandwidth value and the total bandwidth value. And a transmitting step of transmitting a signal received from the subscriber terminal to a station according to the declared bandwidth value when the declared bandwidth value is permitted. 7. The determining step includes a step of comparing a value obtained by subtracting the total bandwidth value from the maximum allowable bandwidth value with the applied bandwidth value.
4. The bandwidth management method described in 1. 8. The transmitting means includes: issuing a polling signal at a timing according to the declared bandwidth value; transmitting a signal received from the subscriber terminal to a station based on the polling signal; The bandwidth management method according to claim 6, comprising: 9. A network management unit that relays a declared bandwidth value from each subscriber terminal transmits the declared bandwidth value from the subscriber terminal to the ATM subscriber device. 9. The network management unit, Receiving the notification that the declaration has been accepted from the ATM subscriber device and transmitting the received notification to the subscriber terminal. 10. A step of counting the number of ATM cells passing within a predetermined period; a step of comparing the number of ATM cells with a number based on a predetermined band value; Changing the route of the received ATM cell when the number is larger than the number based on the predetermined band value.