JP2014011606A - Band allocation method, band allocation device, station side terminating device, and passive optical network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure that in a PON where uplink signals from each user terminal are transmitted to a host network, the configuration is simplified and uplink signal band allocation to each user terminal is made impartially.SOLUTION: A band allocation method of the present invention comprises, in the order mentioned: a transmission request amount acquisition step of acquiring transmission request amounts from each ONU 3; a transmission possible-or-not determination step of ensuring, when determination is made as to whether uplink band allocation to each ONU 3 is possible or not, that a total of transmission request amounts about a single or a plurality of ONU 3 which are connected to each PON port 91 and to which an uplink band is allocatable does not exceed an allocatable band in each PON port 91, and that a total of transmission request amounts about a single or a plurality of ONU 3 which are using a transport 95 and to which an uplink band is allocatable does not exceed an allocatable band in the transport 95; and a transmission possible-or-not notification step of notifying whether uplink band allocation to each ONU 3 is possible or not.

Description

  The present invention relates to a bandwidth allocation technique for uplink signals to each user terminal in a passive optical network system that transmits uplink signals from each user terminal to an upper network.

  A network system that collects uplink signals from each user terminal to a higher level network in a plurality of stages can expect a statistical traffic multiplexing effect and can efficiently use network resources. In Non-Patent Document 1, such a network system is applied to a passive optical network (PON).

  FIG. 1 shows the configuration of a PON accommodated in a prior art switch. In the following description, k is a natural number from 1 to N. Each of the user terminals 4-k-1,..., 4-k-Mk is connected to each of the subscriber-side terminal units (Optical Network Units: ONUs) 3-k-1,. The uplink signal is transmitted.

  In the first stage of concentration, each of the ONUs 3-k-1,..., 3-k-Mk passes through a shared optical power splitter 6-k and an optical fiber 5-k, and a station-side termination device (Optical Line). An uplink signal is transmitted to (Terminal: OLT) 2-k.

  At this time, Dynamic Bandwidth Allocation (DBA) is applied. That is, each ONU 3-k-1, ..., 3-k-Mk notifies the OLT 2-k of the transmission request amount. Then, the OLT 2-k calculates a transmission permission amount based on the transmission request amount, and notifies each ONU 3-k-1, ..., 3-k-Mk of the transmission permission amount. Each ONU 3-k-1,..., 3-k-Mk transmits an uplink signal to the OLT 2-k based on the transmission permission amount.

  In the second stage of concentration, each OLT 2-1,..., 2-N is connected to the upper network 7-1 or the optical network 8-1 or 8-2 via the switch 1 such as a shared layer 2 switch and the optical fiber 8-1 or 8-2. In step 7-2, the uplink signal is transmitted. In this way, N PONs are bundled.

H. Ujikawa, et al., “Multilevel Dynamic Bandwidth Allocation using Buffer Observing for Cousin-Fair Access Systems”, APCC 2011, pp. 2011-2001. 218-223.

  However, if the concentration at each stage is an independent concentration, the bandwidth allocation for each ONU 3 lacks fairness when the concentration at all stages is viewed comprehensively. That is, in the first stage of concentration, each OLT 2-k performs bandwidth allocation fairly to each ONU 3-k-1,..., 3-k-Mk. Then, the switch 1 performs uplink communication to the upper network 7-1 or 7-2 fairly for each of the OLTs 2-1,..., 2-N. However, since the number of ONUs 3-k-1,..., 3-k-Mk subordinate to each OLT 2-k may be different for each OLT 2-k, the bandwidth allocation to each ONU 3 is fair. Lack.

  In view of this, it is conceivable that the bandwidth allocation to each ONU 3 is performed in a fair manner by making the concentration at each stage a coordinated concentration. As such a technique, the technique described in Non-Patent Document 1 and the technique described in FIG. 2 will be described below.

  In the technique described in Non-Patent Document 1, DBA is applied to the second-stage concentrator as well as the first-stage concentrator. That is, each OLT 2-k is notified of the transmission request amount for each dependent ONU 3 from each ONU 3-k-1,..., 3-k-Mk, and notifies the switch 1 of the transmission request amount for the entire dependent ONU 3. To do. Then, the switch 1 calculates the transmission permission amount of the entire dependent ONU 3 based on the transmission request amount of the entire dependent ONU 3, and notifies each OLT 2-k of the transmission permission amount of the entire dependent ONU 3. Then, each OLT 2-k calculates a transmission permission amount for each dependent ONU 3 based on the transmission permission amount of the entire dependent ONU 3, and each of the ONUs 3-k-1,. Notify the allowed transmission amount for each. However, in the technique described in Non-Patent Document 1, the configuration of each OLT 2-k and the switch 1 is complicated.

  In the technique described in FIG. 2, the switch 1 includes the same number of output buffers 13 as the number of ONUs 3 subordinate to the switch 1. The configuration of the prior art switch is shown in FIG. The prior art switch 1 includes a lower port 11-k, a distribution unit 12-k, an output buffer 13-k-1,..., 13-k-Mk, a scheduler 14, an upper port 15, and a congestion detection unit 16. Consists of

  Each lower port 11-k is a port connected to each OLT 2-1. Each distribution unit 12-k distributes an upstream signal from each ONU 3-k-1, ..., 3-k-Mk. Each output buffer 13-k-1,..., 13-k-Mk receives an upstream signal from each ONU 3-k-1,..., 3-k-Mk as a FIFO (First-In First-Out). ) In the order of input, storage and output. The scheduler 14 reads an upstream signal from each ONU 3 so that upstream communication to the upper network 7-1 or 7-2 is performed fairly for each ONU 3. The upper port 15 is a port connected to the upper networks 7-1 and 7-2.

  The congestion detection unit 16 monitors the accumulation amount of the upstream signal in each output buffer 13. Then, when the accumulated amount of the upstream signal in a certain output buffer 13 exceeds a predetermined accumulated amount, the congestion detection unit 16 notifies the OLT 2 corresponding to the output buffer 13 to that effect. Then, the OLT 2 notifies the ONU 3 corresponding to the output buffer 13 of the upstream signal transmission prohibition. As a result, the capacity of each output buffer 13 can be reduced.

  However, in the technique illustrated in FIG. 2, the number of output buffers 13 is equal to the number of ONUs 3 subordinate to the switch 1, so that the configuration of the switch 1 is complicated. Each OLT 2-k can notify each ONU 3-k-1,..., 3-k-Mk of the prohibition of transmission of the uplink signal, but to what extent the bandwidth allocation of the uplink signal is suppressed. I can't decide what to do. Thus, the configuration is complicated and the bandwidth allocation of the uplink signal is not sufficiently fair.

  Therefore, in order to solve the above-mentioned problem, the present invention provides a passive optical network system for transmitting an uplink signal from each user terminal to an upper network, and simplifies the configuration, and provides an uplink signal bandwidth for each user terminal. The purpose is to make the allocation fair.

  In order to achieve the above object, a process of determining whether or not each ONU can transmit based on a transmission request amount of each ONU so as not to exceed an allocatable bandwidth in each access port connected to one or a plurality of ONUs; The process of determining whether or not each ONU can be transmitted based on the transmission request amount of each ONU is performed in a batch rather than in two stages so as not to exceed the allocatable bandwidth in the trunk port connected to the upper network. It was to be. That is, for all of a plurality of ONUs extending over a plurality of access ports, the determination of whether or not each ONU can be transmitted based on the transmission request amount of each ONU is collectively performed.

  Specifically, the present invention provides a passive optical network system including a plurality of access ports connected to one or a plurality of subscriber-side terminators and a trunk port connected to an upper network. A bandwidth allocation method for allocating an upstream band from a termination device to the upper network to each subscriber-side termination device, wherein a transmission request-amount obtaining step for obtaining transmission request amount information from each subscriber-side termination device And when determining whether or not an uplink band can be assigned to each subscriber-side termination device, the one or more subscriber-side termination devices connected to each access port and capable of assigning an uplink band, The total amount of requested transmissions should not exceed the allocatable bandwidth for each access port, and the A transmission permission / inhibition determination step for preventing the total amount of requested transmissions from exceeding the allocatable bandwidth in the trunk port for the one or more subscriber-side termination devices that can use an uplink port and can allocate an upstream bandwidth. And a transmission permission / inhibition notification step for notifying each subscriber-side termination device of whether or not uplink bandwidth allocation to each subscriber-side termination device is possible.

  The present invention also provides a passive optical network system including a plurality of access ports connected to one or a plurality of subscriber-side termination devices and a trunk port connected to a higher-level network. A bandwidth allocation device that allocates an upstream bandwidth to the upper network to each subscriber-side termination device, wherein a transmission request amount acquisition unit acquires information of a transmission request amount from each subscriber-side termination device; and When determining whether or not an uplink band can be assigned to each subscriber-side terminal device, a transmission request amount for the one or more subscriber-side terminal devices that are connected to each access port and can be assigned an upstream band The total amount of the access port does not exceed the allocatable bandwidth in each access port, and the trunk port For the one or more subscriber-side termination devices that can be used and can be allocated an upstream band, a transmission permission / inhibition determination unit that prevents a total amount of transmission request amounts from exceeding an allocatable band in the trunk port; A bandwidth allocation device comprising: a transmission permission / inhibition notification unit that notifies each subscriber-side termination device of whether or not uplink bandwidth allocation to each subscriber-side termination device is possible.

  According to this configuration, the system configuration is simplified by collectively determining whether or not each ONU can be transmitted based on the transmission request amount of each ONU for all of the plurality of ONUs extending over a plurality of access ports. In addition, the bandwidth allocation of the uplink signal can be made fair to each user terminal. Since the number of output buffers may be smaller than the number of ONUs, the system configuration can be simplified.

  Further, the present invention provides that each of the plurality of trunk ports is connected to each of a plurality of higher-order networks, and in the transmission permission / inhibition determining step, the one or a plurality of the plurality of trunk ports that can use the trunk ports and can allocate an uplink band. In the subscriber-side terminal device, a total amount of transmission request amounts is set so as not to exceed an allocatable bandwidth in each trunk port.

  According to this configuration, even when there are a plurality of higher-order output destination networks, by applying the present invention, the system configuration can be simplified, and uplink signal bandwidth allocation is fair to each user terminal. It can be.

  Further, according to the present invention, in the transmission permission / inhibition determining step, it is determined whether or not an uplink band can be assigned to each of the subscriber-side terminators in order of an uplink signal having a high transmission priority and an uplink signal having a low transmission priority. A bandwidth allocation method characterized by the following.

  According to this configuration, even when there are a plurality of types of transmission priorities, by applying the present invention, the configuration of the system can be simplified and the bandwidth allocation of the uplink signal to each user terminal is fair. can do.

  In the transmission permission / inhibition determining step, each of the subscriber-side termination devices is assigned in order from the subscriber-side termination device having a higher allocation priority to the subscriber-side termination device having a lower allocation priority. A bandwidth allocation method characterized by determining whether or not uplink bandwidth allocation is possible.

  Further, according to the present invention, the transmission permission / inhibition determining unit is configured for each of the subscriber-side termination devices in order from the subscriber-side termination device having a higher allocation priority to the subscriber-side termination device having a lower allocation priority. A bandwidth allocating device that determines whether or not an upstream bandwidth can be allocated.

  According to this configuration, it is possible to make the bandwidth allocation of the uplink signal more fair to each user terminal by appropriately setting the priority of allocation.

  In the transmission permission / inhibition determining step, each of the subscriber-side termination devices is assigned in order from the subscriber-side termination device having a higher allocation priority to the subscriber-side termination device having a lower allocation priority. In this bandwidth allocation method, the step of determining whether or not uplink bandwidth allocation is possible is performed in the order of an uplink signal having a high transmission priority and an uplink signal having a low transmission priority.

  According to this configuration, priority is given to bandwidth allocation for upstream data with higher transmission priority, and bandwidth allocation is performed for user terminals with higher allocation priority. Since this is performed preferentially, each user terminal is assigned a band having a transmission priority of each user terminal based on the priority of the assignment, so that fairness among the user terminals can be maintained.

  In addition, the present invention includes a plurality of access ports connected to one or a plurality of subscriber-side terminal devices, a trunk port connected to a higher-level network, and the band allocation device described above. It is a station side terminal device.

  According to this configuration, it is possible to provide a station-side terminal device that simplifies the system configuration and makes the bandwidth allocation of the uplink signal fair to each user terminal.

  The present invention also provides a passive optical network system comprising a plurality of subscriber-side termination devices and the above-mentioned station-side termination device.

  According to this configuration, the configuration of the passive optical network system can be simplified and the bandwidth allocation of the uplink signal can be made fair to each user terminal.

  The present invention can simplify the configuration in a passive optical network system that transmits an uplink signal from each user terminal to an upper network, and can make the bandwidth allocation of the uplink signal fair to each user terminal.

It is a figure which shows the structure of PON accommodated in the switch of a prior art. It is a figure which shows the structure of the switch of a prior art. It is a figure which shows the structure of OLT of this invention. It is a flowchart which shows the determination process of the propriety of transmission of this invention. It is a figure which shows the request | requirement amount list | wrist of this invention. It is a figure which shows the allocation order list | wrist of this invention. It is a figure which shows the ONU information list of this invention. It is a figure which shows the transmission propriety list of this invention.

  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. In the following description, k is a natural number from 1 to N.

(Embodiment)
The configuration of the OLT of the present invention is shown in FIG. When the present invention is compared with the prior art, the ONU 3-k-Mk, the user terminal 4-k-Mk, the optical fiber 5-k, the optical splitter 6-k, the upper networks 7-1 and 7-2, and the optical fiber 8- 1 and 8-2 are the same, but OLT9 is different.

  The OLT 9 includes a PON port 91-k, a bandwidth control message separation / merging unit 92-k, a distribution unit 93-k, buffers 94-1 and 94-2, trunk ports 95-1 and 95-2, and a dynamic bandwidth allocation unit. 96. The dynamic bandwidth allocation unit 96 includes a request amount receiving unit 961, a request amount list 962, a transmission availability determination unit 963, an allocation order list 964, an ONU information list 965, a transmission availability list 966, and a transmission availability notification unit 967.

  Each PON port 91-k is assigned PON port numbers No. 1 to No. N (N> 1 natural number) as an access-side port, and via the optical fiber 5-k and the optical splitter 6-k, ONU3-k-1, ..., 3-k-Mk. The total number of ONUs 3 is K = M1 +. Each of the K ONUs 3 is managed with a unique ONU number of 1 to K. ONU3-k-1, ..., 3-k-Mk are connected to user terminals ONU4-k-1, ..., 4-k-Mk, respectively.

  Trunk ports 95-1 and 95-2 are assigned trunk port numbers 1 and 2, respectively, and upper networks 7-1 and 7-2 are respectively connected via optical fibers 8-1 and 8-2. It is connected to the. It is determined whether the uplink data from each ONU 3 is output to the first upper network 7-1 or the second upper network 7-2. In the present embodiment, there is shown a case where there are two upper networks 7 connected to the trunk port 95, but the number of trunk ports 95, that is, the number of upper networks 7 may be three or more as will be described later in a modification. It may be 1.

  The band control message separation / merging unit 92-k is connected to the PON port 91-k and the dynamic band allocation unit 96. Uplink data from the band control message separation / merging unit 92-k is sent to the distribution unit 93-k, and through the buffers 94-1 and 94-2 connected to the trunk ports 95-1 and 95-2. Output from trunk ports 95-1, 95-2.

  In FIG. 3, although the route of the downlink data is not shown, the downlink data input from the trunk ports 95-1 and 95-2 is output from any of the PON ports 91-k based on the header information of the downlink data. Is determined and sent to the band control message separating / merging unit 92-k connected to an appropriate PON port 91-k.

 Next, details of the operation in the present embodiment will be described. Each ONU 3 transmits information on a transmission request amount to the OLT 9 based on the data amount input from each user terminal 4. Here, assuming that there are four classes of data priorities, each ONU 3 transmits information on the transmission request amount to the OLT 9 for each priority of the four classes of data.

  For example, in the case of EPON defined by IEEE 802.3, each ONU 3 notifies the OLT 9 of information on the requested amount of transmission using a bandwidth control message called REPORT. It is stipulated.

  The transmission request amount information transmitted to the OLT 9 passes through the PON port 91, is separated from uplink data by the band control message separation / merging unit 92, and is sent to the dynamic band allocation unit 96.

  The request amount information sent to the dynamic bandwidth allocating unit 96 is received by the request amount receiving unit 961 and held in the request amount list 962. FIG. 5 shows a required amount list of the present invention. In the request amount list 962, the transmission request amount Req for each data priority for each ONU 3 is recorded in a memory or a register.

  The transmission permission / inhibition determination unit 963 determines whether or not each ONU3 / priority uplink data can be transmitted with reference to the request amount list 962, the allocation order list 964, and the ONU information list 965 in the period of the bandwidth allocation period Tcycle. The result is written in the transmission permission / inhibition list 966. FIG. 4 is a flowchart showing the transmission permission / inhibition determination process of the present invention.

  First, in step S1, the assignable total amount B trunk (x) of the trunk number #x is set as the assignable remaining amount A trunk (x) of the trunk number #x. Here, the total assignable amount of the trunk number #x is the total amount of uplink data that can be output from the trunk port 95 of the trunk port number x during the bandwidth allocation cycle Tcycle, and (trunk port bandwidth of the trunk port number x) × Tcycle. Is required. In this embodiment, since the OLT 9 includes two trunk ports 95-1 and 95-2, the assignable total amount of each trunk port 95 is set as Atrunk (1) and Atrunk (2).

  In step S1, the allocatable total amount BPON (y) of the PON number #y is set as the allocatable remaining amount APON (y) of the PON number #y. Here, the allocable total amount of the PON number #y is the total amount of uplink data that can be input from the PON port 91 of the PON port number y during the bandwidth allocation cycle Tcycle, and (PON port bandwidth of the PON port number y) × Tcycle. -(Bandwidth required for bandwidth control message) In this embodiment, since the OLT 9 includes N PON ports 91, the allocatable total amount of each PON port 91 is set as APON (y) (y = 1 to N).

  In the next step S2, a data priority Pri loop is started. First, Pri = 1 is set, and the process proceeds to the next step S3. After that, when returning from the loop end point of step S12 to step S2 again, Pri is incremented by one. This loop is repeated until Pri reaches the maximum value Primax. In this embodiment, since the data priority is 4 classes, Primax = 4, and the loop of steps S2 to S12 is repeated four times for Pri = 1 to 4. In this embodiment, Pri = 1 is the highest priority class, and Pri = 4 is the lowest priority class.

  In the next step S3, a loop of the allocation order list number L is started. First, L = 1 is set, and the process proceeds to the next step S4. After that, when returning from the loop end point of step S11 to step S3 again, L is incremented by one. In this embodiment, since the total number of ONUs 3 connected to the OLT 9 is K, the loop of steps S3 to S11 is repeated K times for L = 1 to K.

  In the next step S4, the ONU number recorded in the allocation order list number L is read from the allocation order list 964, and the read ONU number is set to i. An allocation order list of the present invention is shown in FIG. The allocation order list 964 is a list in which the ONU 3 is preferentially allocated the bandwidth. The allocation order list number 1 is assigned to the ONU number having the highest allocation priority and the assignment order list number 2 is assigned. The ONU number having the lowest allocation priority is described in the ONU number having the second priority,..., The allocation order list number K.

  Here, regarding the transmission data amount up to the time of step S4, the ONU number of the smallest ONU 3 is assigned to the allocation order list number 1, the ONU number of the next smallest ONU 3 is assigned to the allocation order list number 2, and so on. Is registered in the ONU 3 with a small amount of transmission data up to the time of step S4.

  Alternatively, for the target bandwidth set for each ONU 3 minus the actual transmission bandwidth, the ONU number of the largest ONU 3 is the allocation order list number 1, and the ONU number of the next largest ONU 3 is the allocation order list number If it is registered as No. 2 such as..., Allocation is preferentially performed for the ONU 3 whose actual transmission band is smaller than the target band.

  If the creation method of the allocation order list 964 is set / changed as described above, it is possible to set / change which ONU 3 is preferentially assigned to each user terminal 4. Thus, the bandwidth allocation of the uplink signal can be made fair.

  In the next step S5, the ONU information list 965 is used. FIG. 7 shows an ONU information list of the present invention. For the ONU number i, the number of the trunk port 95 that should output the upstream data from the ONU 3 and the number of the PON port 91 to which the ONU 3 is connected are recorded. The trunk number assigned to the ONU 3 with the ONU number i is read from the ONU information list 965, and this is set as t. The PON port number assigned to the ONU 3 with the ONU number i is read from the ONU information list 965, and this is set as p.

  In the next step S6, the requested amount Req (i, Pri) of the ONU number i and the priority Pri is subtracted from the allocatable remaining amount Atrunk (t) of the trunk number #t. If the subtraction value is 0 or more (YES in step S6), the bandwidth of trunk port 95 with trunk port number t is left, and the process proceeds to step S7. If the subtraction value is smaller than 0 (NO in step S6), the trunk port 95 of the trunk port number t has insufficient bandwidth, so it is determined that the uplink data of the ONU number i and the priority Pri cannot be transmitted, and the process proceeds to step S9. move on.

  In the next step S7, the requested amount Req (i, Pri) of the ONU number i and the priority Pri is subtracted from the allocatable remaining amount APON (p) of the PON number #p. If the subtraction value is 0 or more (YES in step S7), it is determined that the bandwidth of the PON port 91 of the PON port number p is surplus, and the upstream data of the ONU number i and the priority Pri can be transmitted, and the process proceeds to step S8. move on. If the subtraction value is smaller than 0 (NO in step S7), the bandwidth of the PON port 91 of the PON port number p is insufficient, so it is determined that the uplink data of the ONU number i and the priority Pri cannot be transmitted, and the process proceeds to step S9. move on.

  In the next step S8, the fact that the uplink data of ONU number i and priority Pri can be transmitted is recorded in the transmission permission / inhibition list 966, and the process proceeds to step S10. In the next step S9, it is recorded in the transmission permission / inhibition list 966 that the uplink data of the ONU number i and the priority Pri cannot be transmitted, and the process proceeds to step S11. The transmission permission / inhibition list of the present invention is shown in FIG. The transmission permission / inhibition list 966 is a list for holding whether uplink data can be transmitted or not transmitted for each ONU 3 and each data priority.

  In the next step S10, the allocable remaining amount of the trunk number #t is updated from Atrunk (t) before bandwidth allocation to Atrunk (t) -Req (i, Pri) after bandwidth allocation. In step S10, the remaining allocable remaining amount of the PON number #p is updated from APON (p) before bandwidth allocation to APON (p) -Req (i, Pri) after bandwidth allocation.

  Step S11 forms a loop with step S3. If the allocation order list number L currently being processed is less than K, the process returns to step S3. If the allocation order list number L currently being processed is equal to K, the process proceeds to step 12.

  Step S12 forms a loop with step S2. If the priority Pri currently being processed is less than 4, the process returns to step S2. If the priority Pri currently being processed is equal to 4, the processing in FIG.

  The transmission permission / inhibition notification unit 967 reads the transmission permission / inhibition list 966 and generates a transmission permission message that notifies the ONU 3 that can transmit uplink data of which priority data can be transmitted. The generated transmission permission message is sent to the band control message separation / merging unit 92 to which the ONU 3 that is the message transmission target is connected, and to each ONU 3 through the PON port 91 to which the ONU 3 that is the message transmission target is connected. Sent.

  For example, in the case of EPON defined by IEEE 802.3, the transmission permission message is notified from the OLT 9 to each ONU 3 using a bandwidth control message called GATE. A bandwidth control message called GATE is a message that tells how much upstream data each ONU 3 may transmit. When the transmission permission is notified using the GATE message, the transmission permission / inhibition notification unit 967 reads the transmission permission / inhibition list 966, calculates how much uplink data each ONU 3 can transmit, and transmits the uplink data. It is necessary to write the required time in the GATE message.

  The ONU 3 capable of transmitting the uplink data transmits the uplink data corresponding to the transmission permission amount to the OLT 9 in the next bandwidth allocation period according to the transmission permission message.

  In this way, the OLT 9 does not realize the bandwidth control at the PON port 91 and the bandwidth control at the trunk port 95 by the respective dynamic bandwidth control allocation units, but rather than a plurality of ONUs 3 across the plurality of PON ports 91. Can be realized by the collective dynamic bandwidth control allocating unit 96. Therefore, it is possible to make the uplink signal bandwidth allocation fair to each user terminal 4. And the structure of OLT9 can be simplified.

  Furthermore, in the prior art, the output buffers 13 are required for the number of ONUs 3, but in the present invention, the number of buffers 94 may not be the number of ONUs 3, and the number of trunk ports 95 is sufficient. Therefore, the configuration of the OLT 9 can be simplified.

  Further, the transmission possibility determination unit 963 performs processing for performing bandwidth allocation in order from the ONU 3 higher in the allocation order list to the ONU 3 lower in the allocation order list, from priority 1 to the lowest priority class. In order toward priority 4 That is, the transmission capability determination unit 963 gives priority to band allocation with respect to upstream data higher in the priority class and prioritizes band allocation with respect to the ONU 3 higher in the allocation order list. To do.

  Here, when priority is given to bandwidth allocation with respect to the ONU 3 higher in the allocation order list and bandwidth allocation is prioritized for uplink data higher in the priority class, the allocation order The ONU 3 higher in the list is allocated even in the lower band of the priority class, while even the upper band in the priority class may not be allocated to the ONU 3 lower in the allocation order list. Therefore, the fairness among the ONUs 3 cannot be maintained.

  However, when priority is given to bandwidth allocation for upstream data of higher priority class, and priority is given to bandwidth allocation for ONU 3 higher in the allocation order list, On the other hand, the bandwidth of each priority class is assigned based on the assignment order list order. Therefore, fairness among the ONUs 3 can be maintained.

(Modification)
In this embodiment, two trunk ports 95 are arranged, priority is set for uplink data, and an allocation order list 964 is stored. Here, as a first modification, the number of trunk ports 95 may be three or more, or may be one. And as a 2nd modification, it is not necessary to set a priority to uplink data. Furthermore, as a third modification, the assignment order list 964 may not be created.

  In the first modification, when the number of trunk ports 95 is one, it is not necessary to describe the trunk number in the ONU information list 965.

  In the second modification, when the priority is not set for the uplink data, it is not necessary to describe the request amount Req for each priority in the request amount list 962, and the transmission permission / inhibition list 966 indicates whether transmission is possible for each priority. There is no need to list.

  In the third modified example, even when the allocation order list 964 is not created, the determination of whether each ONU 3 can be transmitted based on the transmission request amount of each ONU 3 is collectively performed for all of the plurality of ONUs 3 across the plurality of access ports 91. Therefore, the bandwidth allocation of the uplink signal to each user terminal 4 can be made fair.

  The bandwidth allocation method, bandwidth allocation device, station-side termination device, and passive optical network system according to the present invention simplify the configuration and connect each user terminal to a plurality of PONs connected together to an upper network. On the other hand, the upstream signal bandwidth allocation is fair.

1: Switch 2: OLT
3: ONU
4: User terminal 5: Optical fiber 6: Optical splitter 7: Host network 8: Optical fiber 9: OLT
11: Lower side port 12: Distribution unit 13: Output buffer 14: Scheduler 15: Upper side port 16: Congestion detection unit 91: PON port 92: Band control message separation / merging unit 93: Distribution unit 94: Buffer 95: Trunk port 96: Dynamic bandwidth allocation unit 961: Request amount receiving unit 962: Request amount list 963: Transmission availability determination unit 964: Allocation order list 965: ONU information list 966: Transmission availability list 967: Transmission availability notification unit

Claims (9)

In a passive optical network system including a plurality of access ports connected to one or a plurality of subscriber-side termination devices and a trunk port connected to a higher-level network, an uplink from each of the subscriber-side termination devices to the higher-level network A bandwidth allocation method for allocating bandwidth to each subscriber-side terminal device, comprising:
A transmission request amount acquisition step of acquiring information of a transmission request amount from each of the subscriber-side terminal devices;
When determining whether or not the uplink bandwidth can be assigned to each subscriber-side terminal device,
For the one or more subscriber-side termination devices that are connected to each access port and can be assigned an upstream bandwidth, the total amount of transmission requests is prevented from exceeding the allocatable bandwidth for each access port. With
For the one or more subscriber-side terminating devices that can use the trunk port and can be assigned an upstream band, whether transmission is possible so that the total amount of requested transmissions does not exceed the allocatable band in the trunk port A determination step;
A transmission availability notification step of notifying each subscriber-side termination device of whether or not uplink bandwidth allocation to each subscriber-side termination device is possible;
In sequence. Multiple trunk ports are connected to multiple higher level networks,
In the transmission permission / inhibition determination step, a total amount of transmission request amounts can be assigned to each trunk port for the one or more subscriber-side terminating devices that use each trunk port and can be assigned an upstream band. The bandwidth allocation method according to claim 1, wherein the bandwidth is not exceeded. The transmission permission / inhibition determining step determines whether or not an uplink band can be allocated to each of the subscriber-side terminal devices in order of an uplink signal having a high transmission priority and an uplink signal having a low transmission priority. The bandwidth allocation method according to claim 1 or 2. In the transmission permission / inhibition determination step, whether or not an uplink band can be allocated to each of the subscriber-side termination devices in order from the subscriber-side termination device having a higher allocation priority to the subscriber-side termination device having a lower allocation priority. The bandwidth allocation method according to claim 1 or 2, wherein: In the transmission permission / inhibition determination step, whether or not an uplink band can be allocated to each of the subscriber-side termination devices in order from the subscriber-side termination device having a higher allocation priority to the subscriber-side termination device having a lower allocation priority. The band allocation method according to claim 1 or 2, wherein the step of determining is performed in the order of an uplink signal having a high transmission priority and an uplink signal having a low transmission priority. In a passive optical network system including a plurality of access ports connected to one or a plurality of subscriber-side termination devices and a trunk port connected to a higher-level network, an uplink from each of the subscriber-side termination devices to the higher-level network A bandwidth allocating device for allocating a bandwidth to each subscriber-side terminal device,
A transmission request amount acquisition unit for acquiring information of a transmission request amount from each subscriber-side terminal device;
When determining whether or not the uplink bandwidth can be assigned to each subscriber-side terminal device,
For the one or more subscriber-side termination devices that are connected to each access port and can be assigned an upstream bandwidth, the total amount of transmission requests is prevented from exceeding the allocatable bandwidth for each access port. With
For the one or more subscriber-side terminating devices that can use the trunk port and can be assigned an upstream band, whether transmission is possible so that the total amount of requested transmissions does not exceed the allocatable band in the trunk port A determination unit;
A transmission availability notification unit for notifying each subscriber-side termination device of whether or not uplink bandwidth allocation to each subscriber-side termination device is possible;
A bandwidth allocating device comprising: The transmission permission / inhibition determination unit determines whether or not an uplink band can be allocated to each of the subscriber-side termination devices in order from the subscriber-side termination device having a higher allocation priority to the subscriber-side termination device having a lower allocation priority. The bandwidth allocation apparatus according to claim 6, wherein: With multiple access ports connected to one or more subscriber-side termination devices,
A trunk port connected to the upper network;
The bandwidth allocation device according to claim 6 or 7,
A station-side termination device comprising: A plurality of subscriber-side termination devices;
The station side termination device according to claim 8,
A passive optical network system comprising:

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