JP2000295233A - Frequency band control system for optical network unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assign a frequency band to an optical network unit ONU requiring the frequency band by monitoring cells transmitted in the incoming direction and reducing the assignment of unnecessary frequency bands. SOLUTION: A sender ONU decision section 3 decides a sender ONU from an incoming cell received from an ONU, a cell count section 4 decides whether the received cell is an idle cell or a valid cell, and counts number of consecutive valid and number of consecutive idle cells for each ONU. A polling instruction section 2 inserts a poling signal to each ONU to an outgoing signal as instructed by a band assignment section 1 to request automatic transmission of a reply from each ONU. The threshold of frequency band control is selected, e.g. as follows; when the number of consecutive idle cells is 3 or over, the frequency band assigned to data sent in the incoming direction is judged not to be required and the assigned frequency band is reduced, when the number of consecutive valid cells is 5 or over, it is judged that the frequency band assigned to the data sent in the incoming direction may be deficient and the frequency band is increased if possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bandwidth control system for an optical access device, and more particularly, to an optical access device (ON).
U) monitors the cells transmitted in the upstream direction, reduces unnecessary bandwidth allocation, and
The present invention relates to a band control system assigned to an NU (optical access device).

[0002]

2. Description of the Related Art In a conventional ATM (Asynchronous Transfer Mode) communication system, a set contract bandwidth is not changed until a contract is changed, even if there is no information to be transmitted in the upstream direction. There was a problem that the band was not used effectively. Therefore, it is necessary to effectively use the communication band. Therefore, for example, Japanese Patent Application Laid-Open No. 7-3077
In Japanese Patent Publication No. 37 ("ATM-UNI / LAN communication method and communication device"), the used band and the spare band of the LAN interface are updated each time frame transfer starts and ends, and the band is allocated to each frame. I have. In Japanese Patent Laid-Open Publication No. Hei 10-13415 ("Node device and reserved bandwidth control method"), based on the observed arrival speed of data packets, virtual connection of virtual connection is controlled so as not to fall below the bandwidth corresponding to service quality. The reserved bandwidth amount is dynamically changed.

[0003]

However, in the prior art, it cannot be said that the band is utilized sufficiently effectively.

Accordingly, the present invention monitors the cells transmitted in the upstream direction, reduces the allocation of unnecessary bands, allocates them to ONUs (optical access devices) that require the bands, and efficiently uses the vacant bands. The task is to use it.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a source ONU determining unit connected to two or more optical access units (ONUs), and a determination by the source ONU determining unit. A cell count unit that counts the number of uplink cells for each ONU based on the output of the cell count unit; a band allocation unit that determines a band to be allocated to each of the ONUs based on an output of the cell count unit; Said O
A bandwidth control system for an optical access device, comprising: a polling instruction unit for sending a polling signal to each of the NUs. The number of received empty cells, that is, the number of consecutive empty cells, is counted, and the bandwidth of the ONU in which the number of consecutive empty cells is equal to or more than a predetermined value is allocated to the ONU in which the number of consecutive effective cells is equal to or more than a predetermined value.

That is, in the present invention, the ATM-P
ON (Passive Optical Network)
In the band control of k), the ONU (O
The number of available cells and the number of available cells are monitored for each optical network unit (optical network unit).
The number of band allocations to NUs is reduced, and the unused bands that have been reduced are allocated to ONUs with consecutive valid cells, and the bands are used effectively.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

[0008] In FIG.
The contracted bandwidth is set for each NU. The set band information is inserted into the downstream signal by the polling instructing unit 2 and transmitted to the ONU.

[0009] The upstream cell received from the ONU is
The NU judging unit 3 judges the source ONU, the cell counting unit 4 judges whether the received cell is an empty cell or a valid cell, and counts the continuous number of each cell for each ONU.

[0010] The cell count information for each ONU is sent to the band allocating unit 1. The band allocating unit 1 determines whether the ONU can reduce the band based on the cell count result from the cell counting unit 4. , And determines whether the ONU can increase the bandwidth, and controls the set bandwidth. The polling instructing unit 2 inserts a polling signal for each ONU into a downstream signal as requested by the bandwidth allocating unit 1, and requests automatic transmission from the ONU.

[0011] The source ONU determination unit 3 determines the source ONU of the received upstream signal.

The cell counting unit 4 monitors the received uplink signal, determines whether the received cell is an empty cell or a valid cell, and counts the number of consecutive cells for each ONU.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, two ONUs are used for simplicity.
An embodiment of the present invention will be described as an operation of a stand. Further, the threshold of the band control by the uplink cell received by the band allocating unit 1 is set as follows.

That is, when the number of consecutive vacant cells is 3 or more, it is determined that the band allocated by the data to be transmitted in the upstream direction is not necessary, and the allocated band is reduced.

When the number of consecutive effective cells is 5 or more, it is determined that the data to be transmitted in the upstream direction may be insufficient in the allocated band, and the band is increased if possible.

Further, allocation of the contracted bandwidth to ONU1 and ONU2 is performed by a polling signal as follows. That is, in response to an instruction from the bandwidth allocating unit 1, the polling instruction unit 2 sends a polling signal P to the ONUs 1 and 0NU2.

As shown in FIG. 2A, this polling signal is a signal for automatically transmitting the upstream cell "1" from ONU1 and the upstream cell "2" from ONU2 alternately. Such a polling signal P is transmitted to the downstream OAM (O
peration, Administration a
nd Maintenance: operation and maintenance).

Under the above setting, the upstream cell "1"
Assume that "2" is received.

When the upstream cells "1" and "2" are received, the source ONU determination unit 3 estimates the receiving position of the upstream receiving cell from the polling instruction information inserted into the downstream OAM cell, and It is determined which source ONU is.

The received cell for which the source ONU has been determined is determined by the cell counting section 4 as a valid cell or an empty cell in the OH (overhead) section of the ATM cell. According to the determination result, when the valid cells are consecutive, the count value of the number of consecutive valid cells is incremented by 1, and when the consecutive empty cells are consecutive, the count value of the number of consecutive empty cells is incremented by 1. If not, the cell count is reset. Source O
The NU and the result of counting the number of cells are sent to the band allocating unit 1.

The case where an upstream cell is received as shown in FIG. Here, it is assumed that band control is performed based on the reception status from time T ₀ to time A and time B having a time difference of one frame. The count result at time A is that the number of consecutive valid cells of ONU1 = 6, the number of consecutive empty cells =
It becomes 0. Also, the count result at time B is that the number of consecutive effective cells of ONU2 = 0 and the number of consecutive empty cells = 4.

According to the count result at time A, ONU
For 1, the threshold value 5 for increasing the band is exceeded.
Therefore, the bandwidth allocating unit 1 records the ONU 1 as an object to increase the bandwidth.

On the other hand, from the count result at time B,
Since U2 exceeds the threshold value 3 for band reduction, ONU2 is recorded as a target for band reduction.

Then, the bandwidth of the ONU 2 is reduced, and the unused bandwidth generated is assigned to the ONU 1 so that the ONU 1
Increase the bandwidth of U1. Specifically, as shown in FIG. 2B, W, X, Y, and Z are assigned to ONU1.

FIG. 2 (c) shows an example of the uplink cell reception status after the band control is performed as described above. At time C, the number of consecutive valid cells from ONU1 is 9, and the number of consecutive empty cells is zero. At time D, which differs from time C by one cell, the number of consecutive valid cells from ONU2 is 2, and the number of consecutive empty cells is 0. Therefore, if this state continues, the allocated bandwidth thereafter will remain as it is.

However, if the count of the number of consecutive effective cells of the upstream signal from the ONU 2 is 5 or more, and
When the number of consecutive free cells from the ONU 1 becomes 3 or more, control is performed to reduce the bandwidth equal to or more than the contract bandwidth allocated to the ONU 1 and set the bandwidth of the ONU 2 to the contract bandwidth or more.

The time interval for counting the number of consecutive valid cells and the number of consecutive empty cells may be set arbitrarily irrespective of the example of FIG.

[0028]

According to the present invention described above, the types of cells transmitted in the upstream direction are monitored, the allocation of unnecessary bands is reduced, the ONUs requiring the bands are allocated, and the vacant bands are efficiently used. Can be used

[Brief description of the drawings]

FIG. 1 is a block diagram of a bandwidth control system according to the present invention.

FIG. 2 is a time chart of an upstream frame for explaining the operation of the band control system of the present invention.

[Explanation of symbols]

 1 Band allocation unit 2 Polling instruction unit 3 Source ONU determination unit 4 Cell count unit P Polling signal

Claims (3)

[Claims] 1. A source ONU judging unit connected to two or more optical access units (ONUs), and a cell counting unit counting the number of upstream cells for each ONU based on the judgment of the source ONU judging unit. A band allocating unit that determines a band to be allocated to each of the ONUs based on an output of the cell counting unit;
A bandwidth control system for an optical access device, comprising: a polling instruction unit that sends a polling signal to each of the NUs. The cell count unit includes: Counting the number of vacant cells received, that is, the number of consecutive vacant cells, and allocating a band of ONUs whose number of consecutive vacant cells is equal to or more than a predetermined value to ONUs whose number of consecutive valid cells is equal to or more than a predetermined value. A bandwidth control system for an optical access device. 2. The cell is an ATM (asynchronous transfer mode).
The cell counting unit according to claim 1, wherein the cell counting unit determines whether the cell is valid or empty based on overhead (OH) information of the ATM cell and counts the cell.
A bandwidth control system for an optical access device according to claim 1. 3. The cell counting unit according to claim 1, wherein the count value is incremented by one when the valid cells or the empty cells are continuous, and reset when the cells are not continuous. Optical access equipment bandwidth control system.