JP2013106264A - Band allocation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure fairness in band utilization for ONU accommodated under a high-order SW by fairly allocating a band to be used between OLT and the high-order SW in response to a band request from the ONU.SOLUTION: A band allocation apparatus comprises a prestage concentrator request band management table 21 which manages a weight corresponding to an individual device 1 and a request band of the individual device 1 for each concentrator 2 on a prestage of accommodating the individual device 1, a prestage concentrator band notification section 22 which reads the weight corresponding to the individual device 1 and the request band of the individual device 1 from the prestage concentrator request band management table 21 and calculates a total sum of weights of the requesting individual devices 1 and a total sum of request bands, and a post-stage concentrator band allocation section 33 which allocates an output azimuth band of the concentrator on the prestage by using the total sum of weights for each concentrator 2 on the prestage.

Description

  The present invention relates to an OLT band allocation device that allocates a band to an ONU and an OLT that accommodates the ONU in a PON system.

  Conventionally, a device sharing the bandwidth of the output route is accommodated in a two-stage concentrator, the preceding concentrator 2 allocates a band to the individual device 1, and the subsequent concentrator 3 allocates the bandwidth to the previous concentrator 2. As a system to be allocated (FIG. 5), for example, from a PON system (FIG. 6) using a collective ONU for the preceding line concentrator 2 shown in Patent Literature 1 and Patent Literature 2 or a plurality of devices shown in Patent Literature 3 There is a device in which SWs (SWitches) that accommodate these lines are connected in cascade.

  In these apparatuses, the bandwidth allocated to the preceding line concentrator 2 is dynamically changed for effective use of the output route. The bandwidth allocation to the upstream line concentrator 2 is performed according to the protocol shown in Patent Documents 1 and 2 by the PON dynamic bandwidth allocation protocol from the OLT that is the downstream line collector 3 to the ONU that is the upstream line collector 2. In Patent Document 3, notification is given from the subsequent-stage concentrator 3 to the previous-stage concentrator 2 by a congestion notification.

  However, in these configurations, there is a problem in the allocated bandwidth depending on which of the preceding line concentrators 2 is used, and there is a problem that fairness cannot be ensured between the individual apparatuses 1 that are concentrated in different preceding line concentrators 2. There is. For example, the individual device 1 accommodated in the upstream line concentrator 2 with less congestion has a larger allocated bandwidth than the individual device 1 accommodated in the upstream line concentrator 2 with high congestion, resulting in an unfair allocation.

JP 2002-314564 A JP 2001-94565 A JP 2001-16206 A JP 2003-264588 A JP 2003-264586 A

O. Yoshihara, N .; Oota, and N.A. Miki, “Dynamic Band Allocation Circuit, Dynamic Band Allocation Method, Dynamic Band Allocation Program, and Recording Medium,” US Pat.

  According to the present invention, according to the bandwidth request from the ONU, the bandwidth to be used between the OLT and the upper SW is allocated fairly, thereby ensuring the fairness of the bandwidth usage to the ONU accommodated under the upper SW. Objective.

  In order to achieve the above object, a bandwidth allocating device according to the present invention manages a weight associated with an individual device and a required bandwidth of the individual device for each preceding line concentrator that accommodates the individual device. The weight associated with the individual device and the requested bandwidth of the individual device are read from the requested bandwidth management table and the preceding-stage concentrator requested bandwidth management table, and the sum of the weights of the requested individual device and the requested bandwidth A calculation unit that calculates a sum for each of the preceding concentrators, and a subsequent concentrator that allocates an output route band of the preceding concentrator using the sum of the weights calculated for each of the preceding concentrators calculated by the calculator A device bandwidth allocation unit.

  The bandwidth allocating device of the present invention further includes a rear-stage concentrator shortage counter for counting insufficient allocation to the preceding-stage concentrator, and the rear-stage concentrator bandwidth allocating unit is in descending order of the value of the rear-stage concentrator shortage counter, The output route band of the preceding line concentrator may be calculated and assigned.

  The bandwidth allocating device according to the present invention further comprises a rear-stage concentrator shortage counter for counting insufficient allocation to the preceding-stage concentrator, and the rear-stage concentrator bandwidth allocating unit asymptotically approaches a value of the rear-stage concentrator shortage counter to zero. As described above, the output route band of the preceding concentrator may be calculated and assigned.

  In the bandwidth allocating device of the present invention, the downstream concentrator shortage counter multiplies the output route band by the sum of the weights of the individual devices below the concentrator of the preceding stage, and divides the sum by the sum of the weights of the individual devices. The shortage counter value may be updated by adding a value obtained by subtracting the actual allocation amount from the value.

  In the bandwidth allocating device according to the present invention, the preceding-stage concentrator includes a front-stage concentrator shortage counter that counts the shortage of allocation to the individual devices, and the subsequent-stage concentrator bandwidth allocator in descending order of the values of the preceding-stage concentrator shortage counter. A pre-concentrator bandwidth allocating unit that allocates the output route bandwidth allocated from 1 to the individual device.

  In the bandwidth allocating device of the present invention, the preceding-stage concentrator shortage counter that counts the shortage of allocation to the preceding-stage concentrator, and the subsequent-stage concentrator bandwidth allocator so that the value of the preceding-stage concentrator shortage counter gradually approaches zero. A pre-concentrator bandwidth allocating unit that allocates the output route bandwidth allocated from 1 to the individual device.

  In the bandwidth allocating device according to the present invention, the preceding line concentrator shortage counter is obtained by multiplying the output route band by the weight of the individual device and dividing by the sum of the weights of the individual devices below the previous stage concentrator. The deficiency counter value may be updated by adding a value obtained by subtracting the allocated amount.

  In the bandwidth allocating device according to the present invention, the preceding-stage concentrator shortage counter multiplies the bandwidth allocated to the preceding-stage concentrator by the weight of the individual device and divides by the sum of the weights of the individual devices below the preceding-stage concentrator. The shortage counter value may be updated by adding a value obtained by subtracting the actual allocation amount from the obtained value.

  The above inventions can be combined as much as possible.

  According to the present invention, according to the bandwidth request from the ONU, the bandwidth to be used between the OLT and the upper SW is allocated fairly, thereby ensuring the fairness of the bandwidth usage to the ONU accommodated under the upper SW. be able to.

1 shows a configuration example of a network system according to the present invention. 2 shows a specific example of a network system according to the first embodiment. 4 shows an example of a bandwidth allocation flow according to the first embodiment. 6 shows another embodiment of a bandwidth allocation method according to the first embodiment. An example of the conventional system configuration is shown. 2 shows an example of a PON system that accommodates a collective ONU.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

(Embodiment 1)
The configuration of the present invention will be described with reference to FIG. Here, the network system according to the present embodiment includes an individual device 1, a preceding line concentrator 2, and a subsequent stage concentrator 3. The individual device 1 includes a bandwidth request unit 11. The pre-stage concentrator 2 includes a pre-stage concentrator required bandwidth management table 21, a pre-stage concentrator bandwidth notification unit 22, a pre-stage concentrator bandwidth allocation unit 23, and a pre-stage concentrator shortage counter 24. The subsequent line concentrator 3 includes a subsequent line concentrator request bandwidth management table 31, a subsequent line concentrator congestion determination unit 32, a subsequent line concentrator band allocation unit 33, and a subsequent line concentrator shortage counter 34.

  The upstream line concentrator request bandwidth management table 21 manages the weight associated with the individual device 1 and the required bandwidth of the individual device 1 for each upstream line concentrator 2 that accommodates the individual device 1. The pre-stage concentrator bandwidth notification unit 22 has a function as a calculation unit. The calculation unit reads the weight associated with the individual device 1 and the requested bandwidth of the individual device 1 from the previous stage concentrator requested bandwidth management table 21, and calculates the sum of the weight of the requested individual device 1 and the requested bandwidth. To do. The pre-stage concentrator band allocation unit 23 allocates the output route band allocated from the post-stage concentrator band allocation unit 33 to the individual device 1 using the weight associated with the individual device 1. The pre-stage concentrator shortage counter 24 counts the shortage of allocation to the individual device 1.

  The latter-stage concentrator congestion determination unit 32 has a function as a congestion determination unit. The congestion judgment unit detects congestion from the sum of the requested bandwidths calculated by the pre-stage concentrator bandwidth notification unit 22. The subsequent-stage concentrator band allocation unit 33 allocates the output route band of the previous-stage concentrator 2 using the sum of the weights of the previous-stage concentrator 2 while the subsequent-stage concentrator congestion determination unit 32 determines that the congestion is present. . The latter-stage concentrator shortage counter 34 counts an insufficient allocation to the former-stage concentrator 2.

  An example is shown in which the OLT that houses the ONU is the front-stage concentrator 2 and the SW that collects the output of the OLT is the rear-stage concentrator 3, but it may be a PON that accommodates the collective ONU of Patent Document 1, A plurality of concentrators other than the PON may be concentrated in multiple stages, or may be concentrated in two or more stages (FIG. 5). Instead of a plurality of PONs, the same PON may be used, but a WDM / TDM-PON that communicates using different wavelengths or a PON that communicates by switching or simultaneously using a plurality of redundant paths may be used.

  FIG. 2 shows a specific example of the network system according to the present embodiment. The system of the present application includes ONU1 to ONU4, OLT5 to OLT6, ODN (Optical Distribution Network) that connects ONU1 to ONU4 and OLT5 to OLT6, and SW that collects the output of OLT. The following description will focus on the allocation of the upstream bandwidth from ONU → OLT → SW, but the same applies to the downstream bandwidth allocation. The ONU 1 to ONU 4 have a function as the individual device 1. OLT5 to OLT6 have a function as the concentrator 2 in the previous stage. The SW has a function as the subsequent line concentrator 3.

  The ONU requests a bandwidth from the OLT. The OLT multiplies an ONU that has a bandwidth request by the accommodated ONU by a bandwidth allocation weight value of the ONU, for example, a guaranteed bandwidth value, by multiplying the bandwidth that can be allocated by the OLT, and an ONU that has a bandwidth request by the ONU accommodated by the OLT. Allocate the bandwidth divided by the sum of the weight values of the bandwidth allocation.

  The bandwidth to which the OLT can be assigned is, for example, a bandwidth to which the OLT is assigned from the SW. For bandwidth or fixed assignment for OAM (Operation, Administration, and Maintenance) with the ONU from the bandwidth to which the OLT is assigned. This is a band obtained by adding a band for the OAM with the SW except for the band.

  Bandwidth allocation may be performed with the bandwidth requested by the ONU as an upper limit, or when there is a bandwidth that can be allocated more than the bandwidth requested by all ONUs accommodated in the OLT, the unrequired bandwidth disclosed in Patent Document 4 You may make an assignment. Further, as shown in Non-Patent Document 1, a Deffiit counter may be provided as the pre-stage concentrator shortage counter 24, and the assignment of the counter value asymptotic to zero may be used. The Defectit counter may count with an exponential average, or may count with a sliding window or a jumping window. You may count overallocation instead of underallocation. When non-required bandwidth allocation is performed, or when the bandwidth allocated from the OLT does not match the bandwidth used by the ONU due to the granularity of the bandwidth allocated to prevent fragmentation, the bandwidth used instead of the bandwidth allocated is calculated by the counter. May be used. The same applies to the following description.

Here, the bandwidth allocation method according to the present embodiment will be described with reference to FIG.
The OLT receives a bandwidth request from the ONU (step SL21).
The pre-stage concentrator bandwidth notification unit 22 reads the weight of the requested ONU from the pre-stage concentrator request band management table 21 (step SL22).
The shortage counter value of the requested ONU is read from the preceding line concentrator shortage counter 24 (step SL23).
The pre-stage concentrator bandwidth notification unit 22 notifies the SW of the total requested bandwidth of the ONU to be accommodated and the sum of the bandwidth allocation weights of the ONU requested by the accommodated ONU (step SL24). The SW receives the notification from the OLT (Step SS21).

  Here, the notification of the sum of the bandwidth allocation weights of the requested ONUs holds the bandwidth allocation weight value for each ONU in the SW-side concentrator request bandwidth management table 31 and switches the ONUs with bandwidth requirements to the SW. You may change by notifying. Further, when the sum of the bandwidth allocation weights of the ONU to be notified is the sum of the guaranteed bandwidth, and the requested bandwidth of any ONU is less than the guaranteed bandwidth of the ONU, the requested bandwidth of the ONU is set as the guaranteed bandwidth. Alternatively, the sum may be taken.

  Instead of notifying of the sum of the weights of bandwidth allocation of the requested ONU, the sum of the Defectit counters of all ONUs accommodated by the OLT may be notified. When notifying the sum of the Defectit counter, when integrating the Defectit counter, multiply the band that can be allocated by the OLT that accommodates the ONU by the ratio of the band allocation weight of the ONU and request the band request by the ONU accommodated in the OLT. Instead of using a value obtained by dividing the bandwidth allocation weight of a certain ONU by a value obtained by subtracting the bandwidth allocated to the ONU, the maximum bandwidth that can be allocated to the ONU when there is no congestion, for example, a bandwidth that can be used for allocation in the PON Alternatively, the bandwidth allocated to the ONU is obtained by multiplying the bandwidth of the output route of the SW by the ratio of the bandwidth allocation weight of the ONU and dividing the sum by the sum of the bandwidth allocation weights of the ONU that requires bandwidth in the ONU accommodated in the OLT. It is preferable to use a value obtained by subtracting.

  The latter-stage concentrator bandwidth congestion determination unit 32 reads the requested bandwidth of each OLT from the latter-stage concentrator request band management table 31 and detects congestion. While the post-concentrator bandwidth congestion determination unit 32 detects congestion, the SW performs steps SS22 and SS23.

  The latter-stage line concentrator bandwidth allocation unit 33 performs bandwidth allocation for each OLT and notifies the OLT (step SS22). At this time, the SW multiplies the bandwidth that can be allocated by the OLT that has a bandwidth request in the OLT that accommodates the bandwidth or the bandwidth allocation weight value is not zero by the sum of the bandwidth allocation weight values of the OLT. The bandwidth is divided by the sum of the sums of the OLT bandwidth allocation weight values of the OLTs that have a bandwidth request or the bandwidth allocation weight values are not zero in the OLT accommodated by the SW.

  The bandwidth that can be allocated by the SW is, for example, the bandwidth of the output route of the SW, or the bandwidth obtained by excluding the bandwidth for OAM with the OLT and the bandwidth for fixed allocation from the bandwidth of the output route of the SW. Bandwidth allocation may be performed up to the total sum of bandwidths required by the OLT, or if there is an allocatable bandwidth that exceeds the total sum of bandwidths required by all OLTs accommodated in the SW. The required bandwidth may be allocated.

  Further, when a Defect counter is provided as the subsequent stage concentrator shortage counter 34, the rear stage concentrator shortage counter 34 calculates a shortage counter value for each OLT (step SS23). The allocation of the subsequent concentrator band allocation unit 33 may be an allocation that is asymptotic to zero of the counter value. It is desirable to provide a Defect counter because the allocated bandwidth can be leveled by allocation in a plurality of allocation cycles. Since the delay until the assignment of the OLT to the OLT is reflected in the assignment of the OLT to the ONU occurs, it is desirable that the cycle counted by the SW Defect counter is longer than the cycle counted by the OLT. In addition, when there are sufficient buffers in the SW, as shown in Patent Document 5, switching of band allocation for the OLT according to the queue length in the SW buffer may be used together.

  The OLT receives the notification from the SW (step SL25). The pre-stage concentrator bandwidth allocating unit 23 performs bandwidth allocation to each ONU using the weighting ratio associated with the ONU (step SL26). The pre-stage concentrator shortage counter 24 calculates a shortage counter value for each ONU (step SL27).

  In this embodiment, it is assumed that the output route bandwidth of SW is 1000 Mbps, ONU1 and ONU2 request a bandwidth corresponding to 200 Mbps to OLT5, and ONU3 and ONU4 each have a bandwidth corresponding to 300 Mbps to OLT6. Assume that the guaranteed bandwidth value of each ONU is equal.

  According to the configuration of the invention, the SW assigns the output route bandwidth to the upper limit of the sum of the required bandwidths and assigns the surplus bandwidth at the ratio of the sum of the weights, so that 400 Mbps is assigned to the OLT 5 and 600 Mbps is assigned to the OLT 6.

FIG. 4 shows another embodiment of the bandwidth allocation method according to this embodiment. In this embodiment, instead of step SL26 and step SL27, step SL36 and step SL37 are provided.
In this embodiment, the OLT is provided with a pre-stage concentrator shortage counter 24 for each ONU, and in step SL36, the pre-stage concentrator band allocating unit 23 assigns in order from the ONU having the large shortage counter value.

  In the OLT 5, since the total required bandwidth is equal to the allocated amount, 200 Mbps is allocated to any ONU regardless of whether it is allocated from the ONU 1 or the ONU 2.

  In the OLT 6, since the initial shortage counter is equal, the requested amount of 400 Mbps is first assigned to the ONU 3, and the remaining 200 Mbps is assigned to the ONU 4.

ただし、αは０＜α≦１で定められる平滑化係数である。 In step SL37, the ONU _i pre-stage concentrator shortage counter 24 updates the shortage counter value D _i (t−1) to D _i (t) using the following equation.

Here, α is a smoothing coefficient defined by 0 <α ≦ 1.

Here, _D i in Formula (1), multiplied by the weight _{W i} of ONU _i quota _{B j} to OLT _j, from the values obtained by dividing the sum .SIGMA.W _i of the weight of the OLT _j bottom of ONU, the ONU _i It is calculated by adding a value obtained by subtracting the assigned amount A _i of. That is, the pre-stage concentrator shortage counter 24 updates the value of the shortage counter using the following equation.

  For example, the upstream line concentrator shortage counter 24 of the OLT 6 multiplies the shortage counter value of the ONU 3 by the output route bandwidth 1000 Mbps by the weight 1 of the ONU 3 and divides it by the sum 2 of the weights of the ONUs below the OLT 6, and the allocated amount 400 Mbps. The value obtained by subtracting 100 Mbps is added. The upstream line concentrator shortage counter 24 of the OLT 6 multiplies the shortage counter value of the ONU 4 by the weight 1 of the ONU 4 to the output route bandwidth 1000 Mbps, and subtracts the allocated amount 200 Mbps from the value divided by the sum 2 of the weights of the ONUs below the OLT 6. Add the value 300 Mbps.

  At the next allocation, the OLT 6 allocates the requested amount of 400 Mbps to the ONU 4 having a large shortage counter value, and then allocates the remaining 200 Mbps to the ONU 3.

  In the present application, a bandwidth is allocated to the OLT according to the ratio of the sum of the bandwidth allocation weight values of the ONU having a bandwidth request, and the bandwidth according to the ratio of the sum of the bandwidth allocation weight values is a bandwidth request in the OLT. As a result, any ONU can be allocated with a ratio of the weights of the respective band allocations to the sum of the weights of the ONUs that require a bandwidth among the ONUs accommodated in all OLTs. Therefore, even when an ONU having a bandwidth request is biased to a specific OLT, a bandwidth can be allocated fairly to the ONU without depending on the accommodated OLT.

  Furthermore, since it is not necessary to notify the allocation suppression for individual ONUs from the SW to the OLT, there is no problem of increasing the amount of communication. In addition, since it is not necessary to notify the allocation suppression, there is no problem that unfairness is caused by the order due to the delay until the suppression for sequential communication. In addition, since it is not necessary to hold the allocated bandwidth for each individual ONU in the SW, the processing amount in the SW does not increase. Also, there is no need to perform special processing for integration of the Defect counter at the OLT and SW with suppression.

  In addition, when the notification of the sum of the Defectit counters of all ONUs accommodated by the OLT is used as a notification of the sum of the bandwidth allocation weight values of ONUs having bandwidth requests, a small amount of bandwidth is provided only to some OLTs. Even when ONUs that continuously request requests are accommodated, fairness can be ensured. This is because, regardless of the amount of bandwidth allocation to the accommodated OLT, a common Defect counter is accumulated in all ONUs, and the value of the Defect counter is allocated so as to approach zero.

(Embodiment 2)
In this embodiment, an example in which only the shortage counter calculation method and the allocation method are different from those in the first embodiment will be described. In the present embodiment, the rear stage concentrator shortage counter 34 and the front stage concentrator shortage counter 24 are calculated by round robin so as to gradually approach zero, and the shortage counter value is calculated based on the allocated bandwidth.

  The subsequent concentrator band allocating unit 33 allocates the output route band to the upper limit of the sum of the requested bands, and performs the surplus bandwidth in descending order of the value of the subsequent concentrator shortage counter 34. Since the shortage counter value of the OLT 5 always increases except for the initial state, the subsequent line concentrator band allocation unit 33 allocates 400 Mbps to the OLT 5 and then allocates 600 Mbps to the OLT 6.

  The downstream line concentrator shortage counter 34 multiplies the OLT 5 by multiplying the output route bandwidth 1000 Mbps by the sum of the weights of the ONUs below the OLT 5 and dividing by the sum of the sums of the weights of the OLT 5 and OLT 6 by a total of 4 Mbps. The deficiency counter value is updated by adding the value of 100 Mbps. The downstream line concentrator shortage counter 34 is assigned to the shortage counter of the OLT 6 by multiplying the output route bandwidth 1000 Mbps by the sum 2 of the weights of the ONUs below the OLT 6 and dividing the sum by the sum 4 of the sums of the weights of the OLT 5 and the OLT 6. The shortage counter value is updated by adding −100 Mbps, which is a value obtained by subtracting 600 Mbps.

  In the OLT 6, since the initial shortage counter value of each ONU is equal, the upstream line concentrator bandwidth allocation unit 23 of the OLT 6 allocates 300 Mbps to the ONU 3 and the ONU 4 by round robin.

  The upstream line concentrator shortage counter 24 of the OLT 6 multiplies the value of the ONU 3 and ONU 4 shortage counter by the OLT allocation bandwidth 600 Mbps by the ONU weight 1 and subtracts the allocation amount 300 Mbps from the value obtained by dividing the sum of the ONU weights 2 by the OLT 6. The deficiency counter value is updated by adding 0 Mbps, which is a new value.

  In the OLT 6, the allocation is performed in the same manner after the next allocation.

  The present invention can be applied to the information communication industry.

1: Individual device 2: Previous concentrator 3: Subsequent concentrator 11: Band request unit 21: Pre-concentrator request bandwidth management table 22: Pre-concentrator bandwidth notification unit 23: Pre-concentrator bandwidth allocation unit 24: Pre-concentrator Device shortage counter 31: Rear stage concentrator request bandwidth management table 32: Rear stage concentrator congestion judgment unit 33: Rear stage concentrator bandwidth allocation unit 34: Rear stage concentrator shortage counter

Claims (8)

A previous-stage concentrator request bandwidth management table for managing the weights associated with the individual devices and the required bandwidth of the individual devices for each previous-stage concentrator that accommodates the individual devices;
The weights associated with the individual devices and the required bandwidth of the individual devices are read from the previous-stage concentrator request bandwidth management table, and the sum of the weights of the requested individual devices and the sum of the required bandwidths are collected in the previous-stage concentrator. A calculation unit for calculating each device;
Using the sum of the weights of the preceding concentrators calculated by the calculating unit, a subsequent concentrator band allocating unit that allocates an output route band of the preceding concentrator,
A bandwidth allocation device comprising: A rear stage concentrator shortage counter for counting insufficient allocation to the preceding stage concentrator,
The band allocating device according to claim 1, wherein the subsequent-stage concentrator band allocating unit calculates and allocates an output route band of the preceding-stage concentrator in descending order of the value of the subsequent-stage concentrator shortage counter. . A rear stage concentrator shortage counter for counting insufficient allocation to the preceding stage concentrator,
The said rear stage concentrator band allocation part calculates and allocates the output route band of the said front stage concentrator so that the value of the said rear stage concentrator shortage counter may approach as close to zero. Bandwidth allocation device.   The latter-stage concentrator shortage counter multiplies the output route band by the sum of the weights of the individual devices below the concentrator of the preceding stage, and divides the actual allocation amount from the sum of the sum of the weights of the individual devices. 4. The bandwidth allocation apparatus according to claim 2, wherein the shortage counter value is updated by adding the subtracted value. The preceding-stage line concentrator includes a front-stage line concentrator shortage counter that counts an insufficient allocation to the individual device;
A pre-stage concentrator band allocating unit that allocates the output route band allocated from the post-stage concentrator band allocating unit to the individual devices in descending order of the value of the pre-stage concentrator shortage counter;
The band allocating device according to any one of claims 1 to 4, further comprising: A pre-stage concentrator shortage counter that counts an insufficient allocation to the previous-stage concentrator;
A pre-stage concentrator band allocating unit that allocates the output route band allocated from the post-stage concentrator band allocating unit to the individual apparatus so that the value of the pre-stage concentrator shortage counter asymptotically approaches zero;
The band allocating device according to any one of claims 1 to 4, further comprising:   The pre-stage concentrator shortage counter is a value obtained by multiplying the output route band by the weight of the individual apparatus and dividing by the sum of the weights of the individual apparatuses below the pre-stage concentrator, and subtracting the actual allocated amount. The bandwidth allocating device according to claim 5 or 6, wherein the shortage counter value is updated by addition.   The preceding stage concentrator shortage counter is obtained by multiplying the bandwidth allocated to the preceding stage concentrator by the weight of the individual apparatus and dividing it by the sum of the weights of the individual apparatuses below the previous stage concentrator. The bandwidth allocation apparatus according to claim 5 or 6, wherein the shortage counter value is updated by adding a value obtained by subtracting.

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