JP2002237825A - Stm-pds transmission system and its station side apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deal with a contract between a subscriber side and a station side, and to effectively utilize capacities of optical transmission lines of the station side and the subscriber. SOLUTION: When the station side apparatus 100 receives a data transmission allowance request from the subscriber side unit 150, the apparatus 100 assigns a transmission capacity so as to become a minimum guaranteed transmission capacity or more in the contract between the station side and the subscriber side to an upper limit transmission capacity or less, informs it to the subscriber side unit, and preferentially allows a transmission of a minimum guaranteed transmission capacity or less of the data transmission amount within a past predetermined time to the subscriber side unit. The station side apparatus counts each data transmission amount of a plurality of the subscriber side units at each predetermined time, compares the counted value with a threshold value in response to the upper limit transmission amount and predetermined time in the contract, inhibits the transmission if the counted value exceeds the threshold value, changes the threshold value for next predetermined time to a low value, and compares the threshold value with the counted value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a point-multipoint type STM-PDS (Synchronous Transfer M
ode-Passive Double Star) transmission system and its station side device.

[0002]

2. Description of the Related Art Generally, in an STM-PDS transmission system, a subscriber line terminal (SLT), which is a terminal equipment for a subscriber side of an optical line terminal,
A plurality of network terminating devices (ONU: Optical Netw
ork Unit), an optical fiber is placed between the SLT and the optical coupler, and an optical fiber is placed individually between the optical coupler and a plurality of ONUs. The optical signal between the SLT and the ONU is multiplexed and demultiplexed. For this reason, multiplexing is performed between the SLT and the optical coupler, and there is a limit in the transmission capacity. Therefore, when a large amount of data is transmitted in an upstream direction by one ONU, data transmission by another ONU is inhibited.

Therefore, as a conventional method (conventional example 1) for preventing this problem, according to Japanese Patent Application Laid-Open No. Hei 10-336186, the station side receives a band from the subscriber side (data transmission capacity per unit time: synonymous with throughput). And a method of allocating a bandwidth (data transmission capacity) for each fixed area for each request source, a certain amount for each reception time, and a certain amount for each request source and reception time. ing. As another conventional method (conventional example 2), according to Japanese Patent Laid-Open No. 11-341037, a subscriber notifies a station of a transmission permission request and a transmission data amount, and the station dynamically determines an unused area. Assignment methods have been proposed.

[0004]

By the way, in such an STM-PDS transmission system, usually, a transmission time per unit time between the station side and the subscriber side when the transmission is performed in the uplink direction from the subscriber side to the station side. Contracts and agreements that stipulate the minimum guaranteed transmission amount and the maximum transmission amount of
In some cases, the line capacity is unilaterally determined in advance, and the subscriber simply agrees to this. Hereinafter, contracts, agreements, agreements, and the like between these offices and subscribers are collectively referred to as contracts. However, since the transmission capacity (band) is allocated to each fixed area in the above-mentioned conventional example 1, and the unused area is simply dynamically allocated in the conventional example 2, it corresponds to the contract between the station side and the subscriber side. There is a problem that cannot be done. Also, since the maximum transmission capacity on the subscriber side differs individually, it is necessary to cope with this.

[0005] The first invention has been made in view of the above-mentioned problems of the prior art,
It is an object of the present invention to provide an STM-PDS transmission system capable of responding to a contract concluded between a station and a subscriber, and a station apparatus thereof. It is another object of the present invention to provide an STM-PDS transmission system capable of effectively utilizing the capacity of an optical transmission path between a station and a subscriber, and a station apparatus thereof.

[0006]

According to a first aspect of the present invention, in order to achieve the above object, when a station side device receives a data transmission permission request from a subscriber side device, a communication between the station side and the subscriber side is performed. The transmission capacity is allocated so that it is equal to or greater than the contractual minimum guaranteed transmission capacity and equal to or less than the upper limit transmission capacity, and this is notified to the subscriber unit. This is transmitted to the device. In addition, transmission is preferentially permitted to a subscriber device whose data transmission amount within a past predetermined time is equal to or less than the minimum guaranteed transmission capacity.

That is, according to the first aspect, a point-multipoint two-way communication is performed between an optical line terminal and a plurality of subscriber side devices via an optical transmission path based on a contract for a data transmission capacity. In the STM-PDS transmission system, the subscriber unit transmits a data transmission permission request to the station side device, and when the station side device receives the data transmission permission request, the subscriber unit joins the station side. The transmission capacity is allocated so as to be equal to or greater than the contractual minimum guaranteed transmission capacity between the subscribers and equal to or less than the upper limit transmission capacity, and this is notified to the subscriber unit, and the subscriber unit is assigned. An STM-PDS transmission system is provided, wherein data is transmitted to the optical line terminal at a capacity or less.

According to the first aspect of the present invention, a point-multipoint type bidirectional communication is performed between an optical line terminal and a plurality of subscriber units via an optical transmission path based on a contract for a data transmission capacity. In the station side device of the STM-PDS transmission system for performing communication, when receiving a data transmission permission request from the subscriber side device, the contracted minimum guaranteed transmission capacity between the station side and the subscriber side is greater than or equal to , A transmission capacity is allocated so as to be equal to or less than the upper limit transmission capacity, and the transmission capacity is notified to the subscriber side apparatus.

According to a second aspect of the present invention, in order to achieve the above object, each of the plurality of subscriber units counts each data transmission amount at a predetermined time interval, and counts the data transmission amount according to the count value and the contractual upper limit transmission capacity and the predetermined time period. When the count value exceeds the threshold value, transmission is prohibited and the threshold value in the next predetermined time is changed to a lower value.

In other words, according to the second aspect of the present invention, two-way communication of a point / multipoint type is performed between an optical line terminal and a plurality of subscriber side devices via an optical transmission path based on a contract for a data transmission capacity. In the STM-PDS transmission system, the station-side device counts each data transmission amount of the plurality of subscriber-side devices at predetermined time intervals, and counts this count value with the contractual upper limit transmission capacity and the predetermined time period. If the count value exceeds the threshold value in comparison with the threshold value, transmission is prohibited, and the threshold value in the next predetermined time is changed to a lower value and compared with the count value.
A TM-PDS transmission system is provided.

According to the second aspect of the present invention, a point-multipoint type bidirectional communication is performed between an optical line terminal and a plurality of subscriber units via an optical transmission path based on a contract for a data transmission capacity. The station apparatus of the STM-PDS transmission system for performing communication counts each data transmission amount of each of the plurality of subscriber apparatuses at predetermined time intervals, and counts the count value, the contracted upper limit transmission capacity, and the predetermined time. STM is characterized in that when the count value exceeds the threshold value as compared with the threshold value, transmission is prohibited, and the threshold value in the next predetermined time is changed to a lower value and compared with the count value.
A station device of a PDS transmission system is provided.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of an STM-PDS transmission system and a station side device according to the present invention. FIG. 2 is an explanatory diagram showing a configuration of an upstream frame of the transmission system of FIG.
Is an explanatory diagram showing a data amount counting period, FIG. 4 is a flowchart showing a priority assignment process, and FIG. 5 is an explanatory diagram showing a priority assignment process.

In FIG. 1, a plurality of subscriber units 150
-1, 150-2 to 150-n (the whole is denoted by 150)
Are both configured by a network termination unit (ONU) and the like, and are connected to a telephone terminal, a personal computer, and the like. The optical line terminal 100 includes a subscriber line terminal (SLT) and an operating system. Each O of the plurality of subscriber-side devices 150-1, 150-2 to 150-n
NU and optical star type optical coupler (hereinafter, star coupler) 11
0 is connected via each optical fiber 111, and the star coupler 110 and the SLT of the optical line terminal 100 are connected via one optical fiber 111. Although not shown, the optical line terminal 100 is connected to another subscriber side device via a central office exchange or the like.

[0014] A plurality of subscriber units 150 to the office unit 1
When transmitting in the upstream direction to 00, the subscriber unit 1
Optical signals of the common wavelength λ1 from each of the 50 ONUs are multiplexed by the star coupler 110 in a time division multiple access (TDMA) system. From the central unit 100 to the subscriber unit 1
In the case where transmission is performed in the downlink direction to
The optical signal multiplexed by the time division multiplexing (TDM) method at the wavelength λ2 and transmitted by the SLT is separated by the star coupler 110 and transmitted to the ONU of each subscriber unit 150. In addition, in addition to the above-described wavelength multiplexing (WDM) system as the up-down multiplexing system, the present invention separates up-down transmission time zones using a single-core optical fiber to perform bidirectional communication. Realizing TCM (Time Compression Mul
SDM (Spac) that realizes bidirectional communication by using a two-core optical fiber for the tiplexing method and the vertical direction
e Division Multiplexing).

Each of the plurality of subscriber units 150 includes a transmission permission request transmission / transmission permission reception unit 151 and a data transmission unit 1
52. Transmission permission request transmission / transmission permission receiving unit 15
1 notifies the station side device 100 of a transmission permission request in advance before actual data transmission, and receives the transmission permission and the permitted capacity transmitted from the station side device 100 in response to the transmission permission request. The data transmitting section 152 transmits data within the range of the transmission capacity permitted from the optical line terminal 100.

The optical line terminal 100 includes a transmission permission request storage unit 10
1, a minimum guaranteed capacity / upper limit capacity storage unit 102, a data amount integration counter 103, a capacity allocating unit 104, and a transmission permission / capacity notifying unit 105. The minimum guaranteed transmission amount and the upper limit transmission amount in the contract concluded between the office and each subscriber are accumulated for each subscriber. The transmission permission request storage unit 101 stores transmission permission requests from each of the plurality of subscriber units 150, and the data amount integration counter 103 stores the data amount per past unit time transmitted from the subscriber unit 150. Is multiplied. The capacity allocating unit 104 assigns a transmission capacity (time slot area) to each subscriber unit 150
Is determined for each subscriber unit 150, and the transmission permission / capacity notifying unit 105 notifies the subscriber unit 150 of the transmission permission and the permitted capacity to the subscriber unit 150.

FIG. 2 shows the structure of one frame in the upward direction. One frame includes a plurality of subscriber units 150-1,
Area ONU allocated for each of 150-2 to 150-n
1. Each of the ONUs 2 to ONUn and a shared area, and the shared area is, for example, four shared areas # in 100-byte units.
1 to # 4. When transmitting data to the optical line terminal 100 using the shared areas (# 1 to # 4), the subscriber unit 150 determines the transmission permission request and the number of the shared areas (# 1 to # 4). Send.

Next, a schematic operation will be described. First, in the subscriber unit 150, the transmission permission request transmission / transmission permission receiving unit 151 notifies the station side device 100 of the transmission permission request and the number of the shared areas # 1 to # 4 in advance before the actual data transmission. In the side device 100, the transmission permission request storage unit 101 stores the transmission permission request for each subscriber side device 150.

The capacity allocating unit 104 determines whether or not the minimum guaranteed transmission amount is equal to or larger than the minimum guaranteed transmission amount based on the minimum guaranteed transmission amount and the upper limit transmission amount stored in the minimum guaranteed capacity / upper limit capacity storage unit 102 for each subscriber unit 150 in advance. And the shared areas # 1 to #
Determine the number 4 (and its position). Then, the transmission permission / capacity notifying section 105 notifies the transmission permission request transmission / transmission permission receiving section 151 of the subscriber side device 150 of the transmission permission including the number of the shared areas # 1 to # 4 (and their positions). The data transmission unit 152 of the subscriber unit 150 transmits data to the optical line terminal 100 using the shared area.

As shown in FIG. 3, the data amount integration counter 103 counts the transmission data amount at a predetermined time α in the past from the current time t for each subscriber unit 150, and
This is updated at predetermined time intervals, and the capacity allocation unit 104 performs a priority allocation process as shown in FIG.

In FIG. 4, first, an O for giving a transmission permission
ONU number k (k = 1, 2-n) to search for NU
Is initialized (k = 1) (step S1), and if all the ONUs have not been searched, the process proceeds from step S2 to step S3. In step S3, it is determined whether or not there is a transmission permission request from the ONU of the number k. If there is no transmission permission request, the process jumps to step S5. O
It is determined whether or not the transmission data amount at the time α from the NU is equal to or less than the minimum guaranteed transmission amount. Then, if the transmission data amount ≦ the minimum guaranteed transmission amount, it is determined that transmission permission is given to the ONU with the number k (step S11). The process proceeds to step S5 without giving.

In step S5, the ONU number k is incremented by one, and then the flow returns to step S2 to turn on all ONUs.
Similarly, if there is a transmission permission request for U, the time α
By determining whether the transmission data amount is equal to or less than the minimum guaranteed transmission amount, it is determined whether or not transmission permission is given.
When this process (S2 to S5) is completed for all ONUs, the process proceeds from step S2 to step S6.

In step S6, similarly, the ONU number k is initialized (k = 1), and if all ONUs have not been searched, the process proceeds from step S7 to step S8.
In step S8, it is determined whether or not there is a transmission permission request from the ONU of the number k. If there is no transmission permission request, the process jumps to step S10. If there is a transmission permission request, the process proceeds to step S9 to proceed to step S9. Time α from ONU
It is determined whether or not the amount of transmission data is equal to or less than the upper limit transmission amount. If the transmission data amount ≦ the upper limit transmission amount, it is determined that the transmission permission is given to the ONU of the number k (step S11). On the other hand, if the transmission data amount ≦ the upper limit transmission amount, the transmission permission is given. To step S10.

In step S10, the ONU number k is incremented by one, and the process returns to step S7 to return all the O
Similarly, when there is a transmission permission request for the NU, it is determined whether the transmission permission is given by determining whether the transmission data amount at the time α is equal to or less than the upper limit transmission amount. When this process (S6 to S10) is completed for all ONUs, this priority allocation process is completed.

FIG. 5 shows a specific process. In FIG. 5, the minimum guaranteed transmission amount for the subscriber unit 150-1 =
2, upper limit transmission amount = 5, minimum guaranteed transmission amount for subscriber unit 150-2 =
4, upper limit transmission amount = 5, minimum guaranteed transmission amount for subscriber unit 150-3 =
1, upper limit transmission amount = 3. Since the amount of transmission per unit time is also referred to as speed, it is indicated as "speed" in the figure.

If the transmission data amount at a predetermined time α in the past is: subscriber unit 150-1 = 4, subscriber unit 150-2 = 3, subscriber unit 150-3 = 2, The amount of data transmitted per unit time in the past is equal to or less than the minimum guaranteed transmission amount.
Only the subscriber units 150-1 to 150-3.
When the traffic increases and the data transmission volume approaches the line capacity, for example, when the transmission request is transmitted at the same time, the transmission is preferentially permitted to the subscriber unit 150-2.

<Second Embodiment> Next, a second embodiment will be described with reference to FIG. In the second embodiment,
For the upper limit transmission amount Bmax per unit time Ts on the contract, the threshold value Ds for a shorter time T0 (<Ts)
(= Bmax × T0) is set, and the transmission amount is controlled while adaptively changing the threshold value Ds according to the transmission amount at each time T0. (1) First, as shown in FIG. 6, the amount of transmission data from the subscriber unit 150 at the unit time T0 is counted, and when the unit time T0 elapses, the counter is cleared and the next unit time 2T0-T0 The transmission data amount is counted, and this is repeated for each unit time T0. (2) Then, the subscriber unit 15 at the unit time T0
When the transmission data amount from 0 is equal to or less than the threshold value Ds, transmission permission is given. On the other hand, when the transmission data amount exceeds the threshold value Ds, the counter is stopped at the time when the transmission data amount exceeds the threshold value Ds, and transmission is prohibited. The transmission prohibition is continued until the unit time T0 ends.

(3) The threshold value Ds at the previous unit time T0
Exceeds the difference ΔD between the count value and the threshold value Ds.
(= Ds−count value) is calculated, and the threshold value at the next unit time T0 is set to Ds−ΔD. That is, the unit time T0
Each time, when the transmission data amount exceeds the threshold Ds, the threshold D
s, the threshold Ds of the n-th unit time nT0
(N) becomes Ds (n) = Ds−ΔD (n−1). If the threshold value Ds does not exceed the threshold value Ds in the previous unit time T0, the threshold value D
s is a default value (= Bmax × T0). here,
The unit time T0 is set to a value that is long enough to ignore the influence of traffic fluctuation and that the stoppage time of transmission permission is as short as possible.

[0029]

As described above, according to the first aspect of the present invention, when the station side device receives a data transmission permission request from the subscriber side device, the contract between the station side and the subscriber side is executed. A transmission capacity is allocated so as to be equal to or more than the minimum guaranteed transmission capacity and equal to or less than the upper limit transmission capacity, and this is notified to the subscriber side apparatus, and the subscriber side apparatus transmits data to the station side apparatus with the allocated capacity or less. With this configuration, it is possible to deal with a contract between the office and the subscriber. According to the second invention, each data transmission amount of the plurality of subscriber units is counted at predetermined time intervals, and the count value is compared with a contract upper limit transmission capacity and a threshold value according to the predetermined time. When the threshold value exceeds the threshold value, transmission is prohibited, and the threshold value in the next predetermined time is changed to a low value, so that the capacity of the optical transmission line between the station side and the subscriber can be effectively used.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of an STM-PDS transmission system and a station side device thereof according to the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an upstream frame of the transmission system of FIG. 1;

FIG. 3 is an explanatory diagram showing a data amount counting period.

FIG. 4 is a flowchart showing priority assignment processing;

FIG. 5 is an explanatory diagram showing priority assignment processing;

FIG. 6 is an explanatory diagram illustrating a correction process of an upper limit transmission capacity according to the second embodiment;

[Explanation of symbols]

 100 Station side device 150 Subscriber side device

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuhiro Shinako 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 5K033 CB06 CB17 DA15 DB02 DB22 EA02 EA07

Claims (8)

[Claims] 1. A point-multipoint type bidirectional communication between an optical line terminal and a plurality of subscriber side devices via an optical transmission path based on a contract for a data transmission capacity.
In the TM-PDS transmission system, when the subscriber unit transmits a data transmission permission request to the station side device, and when the station side device receives the data transmission permission request, the station side and the subscriber side A transmission capacity is allocated so as to be equal to or more than the contractual minimum guaranteed transmission capacity and equal to or less than the upper limit transmission capacity during the contract, and the subscriber side device is notified of the transmission capacity, and the subscriber side device is equal to or less than the allocated capacity. Transmitting data to the optical line terminal in the STM-
PDS transmission system. 2. The station device further accumulates a data transmission amount within a predetermined time in the past for each of the plurality of subscriber devices,
2. The method according to claim 1, wherein when receiving a data transmission permission request from the plurality of subscriber units, the transmission unit preferentially permits transmission to a subscriber unit whose data transmission amount is equal to or less than the minimum guaranteed transmission capacity. The STM-PDS transmission system according to the above. 3. A point-multipoint two-way communication between an optical line terminal and a plurality of subscriber-side devices via an optical transmission path based on a contract for a data transmission capacity.
In the TM-PDS transmission system, the station-side device counts each data transmission amount of the plurality of subscriber-side devices for each predetermined time, and according to the count value, the contract upper limit transmission capacity, and the predetermined time. STM-PD wherein when the count value exceeds the threshold value as compared with the threshold value, transmission is prohibited, and the threshold value in the next predetermined time is changed to a lower value and compared with the count value.
S transmission system. 4. The method according to claim 3, wherein when the threshold value of the next predetermined time is changed to a low value, the threshold value is reduced by a value obtained by subtracting the threshold value of the predetermined time from the count value of the previous predetermined time.
The STM-PDS transmission system according to the above. 5. A point-multipoint type bidirectional communication between an optical line terminal and a plurality of subscriber side devices via an optical transmission path based on a contract for data transmission capacity.
In the station side device of the TM-PDS transmission system, when a data transmission permission request is received from the subscriber side device, the contracted minimum guaranteed transmission capacity between the station side and the subscriber side is equal to or more than the contract upper limit, and the upper limit is set. A station apparatus in an STM-PDS transmission system, wherein a transmission capacity is allocated so as to be less than a transmission capacity, and the transmission capacity is notified to the subscriber apparatus. 6. A data transmission amount within a predetermined time in the past is accumulated for each of the plurality of subscriber units, and when a data transmission permission request is received from the plurality of subscriber units, the data transmission amount is reduced. 6. The ST according to claim 5, wherein transmission is permitted to the subscriber unit having a transmission capacity equal to or less than a minimum guaranteed transmission capacity.
A station device of the M-PDS transmission system. 7. A point-multipoint type bidirectional communication via an optical transmission path based on a contract for data transmission capacity between an optical line terminal and a plurality of subscriber side devices.
In the station-side device of the TM-PDS transmission system, each data transmission amount of the plurality of subscriber-side devices is counted at predetermined time intervals, and the count value is determined according to the contracted upper limit transmission capacity and the predetermined time period. The station side of the STM-PDS transmission system, characterized in that when the count value exceeds the threshold value compared to the threshold value, transmission is prohibited and the threshold value in the next predetermined time is changed to a lower value and compared with the count value. apparatus. 8. The method according to claim 7, wherein when the threshold value of the next predetermined time is changed to a low value, the threshold value is reduced by a value obtained by subtracting the threshold value of the predetermined time from the count value of the previous predetermined time.
A station device of the STM-PDS transmission system described in the above.