JP2003318846A - Method for controlling delay measurement of optical burst transmission/reception network and device therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an influence of data when measuring delay on delay fluctuation when band allocation to a slave device is large or when delay measurement time is long. <P>SOLUTION: In this method for controlling delay measurement of an optical burst transmission/reception network having a master device and a plurality of slave devices that share a transmission medium and a transmission line, in which the master device is provided with a process for measuring transmission time according to distance between the slave devices and the master device and a process for controlling allocation of use bands of the slave devices and in which the slave devices are provided with processes for transmitting transmission signals on the basis of allocation control of the use bands to the master device, the master device is provided with a process for controlling start intervals of delay measurement instructions on the basis of allocation information of the use bands to the slave devices and/or size of a delay measurement window. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a delay in an optical burst transmission / reception network in which a plurality of child devices share a transmission medium and a transmission band, and each child device transmits data to the parent device by band control of the parent device. The present invention relates to a measuring method and an apparatus thereof.

[0002]

2. Description of the Related Art In an optical burst transmission / reception network, a plurality of child devices share a transmission medium and a transmission band, a parent device measures a transmission time according to a distance from each child device, and each child device has its own transmission time. Notify the delay time according to the measured value, each child device adds a delay to the transmission signal to the parent device according to the value, the parent device controls the allocation of the bandwidth used by each child device, and each child device A network based on the method of transmitting data to a parent device based on the above control of the device. In this optical burst transmission / reception network, a plurality of child devices share a transmission medium and a transmission band, and each child device transmits data to the parent device by band control of the parent device.
-T Recommendation G. 983.1 (Broadband optical access sy
stems based on Passive Optical Networks (PON) 1
998/10). FIG. 4 shows this ITU-T recommendation G.264. 98
3.1 Figure 5 / G.983.1-Generic physical configur
ation of the Optical Distribution Network, n
One ONU (Optical Network Unit) and one OLT
It is an explanatory view showing an optical burst transmission / reception network provided with (Optical Line Termination) and the like. In the figure, OLT corresponds to a parent device, ONU corresponds to a child device, and OD
N (Optical Distribution Network) is a transmission medium configured by an optical fiber, an optical multiplexer / demultiplexer, and the like.
Also, Figure 5 shows Figure 11 / G.983.1-Frame for Recommendation.
mat for 155.52 / 155.52 Mbit / s PON, OL
It is explanatory drawing which showed the data format of the direction from T to ONU (henceforth "downward direction") and the direction from ONU to OLT (henceforth "upward direction"). In this configuration, it is premised that fixed-length cells of 53 bytes in the down direction and 56 bytes in the up direction are transmitted.
Downlink data is broadcast from the OLT to all ONUs, and upstream data is one O per time slot of each cell.
A method in which the transmission of NU is permitted by the OLT in advance,
Data is transmitted. Here, the permission of data transmission in each time slot in the up direction, that is, the notification of the band allocation information is transmitted by the supervisory control cell (PLO) defined in the format of the downlink data and transmitted in 28 cell cycles.
AM: Physical Layer Operations Administration and
Maintenance cell) by inserting band allocation information. The insertion position of this allocation information is Ta
ble 8 / G.983.1-Payload content of downstream PLOAM
It is each byte designated as grant1 to grant27 shown in the cell. Since there are 53 slots for one frame in the upstream direction, the first P in the downstream frame
Grant 1 to grant 27 in the LOAM cell assign allocation information of the 1st to 27th time slots in the upstream frame, grant 1 to grant 26 in the 2nd PLOAM cell of the downlink frame from 28th to 53 in the upstream frame. The allocation information of the th time slot is shown.

[0003] The format of the above grant is T
able 10 / G.983.1-Specification of the grants. In the table, the type of grant assigned to each ONU for use in the upstream slot is Data grant or P.
It is a LOAM grant. Of these, PLOAM grant is assigned for transmission of uplink supervisory control cells, and Data grant is used for assignment for normal data transmission. Da
The value used for ta grant is arbitrary except some reserved values. Then, in order for each ONU to recognize the allocation, the value of the Data grant used by each ONU in advance is PL by a message included in the downlink PLOAM cell for each ONU.
It is notified from the OLT together with the value of OAM grant. The format of the message is described in Chapter 8.3.8.2.1 Down of the Recommendation.
Grant_allocation mes in stream message formats
Shown in sage. This message is sent to one ONU and the Data grant and
The value of PLOAM grant is shown. The ONU receives this message and stores its value so that the OLT can use it later.
1 to gra in the PLOAM cell transmitted by
When nt27 has that value, it can be recognized that its own upstream band allocation exists.

As described above, the OLT defines a Data grant and a PLOAM grant having different values for each ONU, and before the ONU performs upstream data transmission.
By sending the Grant_allocation message,
It is possible to manage the allocation of uplink slots to each ONU. In addition, the ONU does not transmit data in slots that are not allocated to itself,
It is possible to perform transmission without causing data collision on the upstream transmission path.

Since the allocation of the time slot in the upstream frame is controlled by the OLT to all the ONUs connected to the OLT, as long as each ONU follows this control, each upstream time slot has one. It can only be used by one ONU. However, it is not possible to actually transmit data by sharing the upstream transmission path only with this band control function. The reason is each O
This is because the distance between the NU and the OLT varies, and the phase of the upstream frame recognized by each ONU does not match when viewed from the OLT. According to the above recommendation, each ON
The distance between U and OLT is allowed to vary in the range of 0 to 20 km, and this variation in the distance difference must be dealt with naturally in consideration of the geographical positional relationship between the actual accommodation station and the subscriber's house. This is a condition that must be met. Since this difference in distance appears as a difference in data transmission delay, in order for the upstream data sent from each ONU to be multiplexed without collision at the time of arriving at the OLT, the OLT has to set this transmission delay. O
It is necessary to measure each NU, determine the additional delay amount in the ONU based on the measurement result, and notify each ONU. At the same time, each ONU also needs to add the notified delay amount to the upstream data and send it to the OLT. This additional delay amount is smaller for ONUs with larger measured values, and is larger for ONUs with smaller measured values, and the phase of the upstream frame recognized by each ONU when the downlink frame sent from the OLT is used as a reference. Set so that they match when viewed from the OLT. The delay measurement operation performed by the OLT based on the above recommendation is called ranging.

FIG. 6 is an explanatory diagram showing the relationship between the distance between the OLT (station-side device) and the ONUs (devices a, b, c) and the delay amount when delay control is normally performed. In the figure, the part of the band allocation instruction from the station side is an example of the allocation status to each ONU in each slot in the upstream direction, and “a”, “b” and “c” are the device a and the device a, respectively.
The assignment to device b and device c is shown. In addition,
This one box corresponds to the ATM cell shown in FIG. In order to perform delay control, as shown in the figure, the applicable transmission delay time (T) is set to be equal to or greater than the transmission delay with the farthest device, and the transmission delay time of each device is subtracted from this T. May be set as the respective additional delay amounts. Due to the additional delay amount set in each ONU, the total delay time at the time when the signal from each device is received by the OLT in the upstream frame is aligned with T, so that time-division multiplexing operates normally. To do.

Before the delay measurement is performed, the
The NU delay amount is not fixed. Therefore, as the procedure of delay measurement, first, the OLT uses O
The process starts by temporarily stopping the bandwidth allocation to the NU and delivering the delay measurement grant to the measurement target ONU. FIG. 7 is an explanatory diagram showing the states of band control and delay control at the time when delay measurement is started. In the band allocation instruction from the station side, an empty slot indicates that no device is allocated. In addition, after this non-allocated empty slot, a grant for delay measurement is assigned to the device x as a delay measurement target. The ONUx for which delay measurement has not been performed has not notified the delay amount to be added by itself from the OLT. Therefore, when the delay measurement grant is distributed from the OLT, the delay is not added and the upstream direction Cell is sent. OLT is 0
During the possible measurement range such as 20 km, the bandwidth allocation to the other ONU is stopped, so that the source cell of the other ONU does not collide with the delay measurement cell,
It is possible to measure the time from the generation of the delay measurement grant to the arrival of the transmission cell of the delay measurement target ONU.

The OLT calculates the delay amount to be added by the ONU from the delay time measured in the above procedure and notifies the calculation result. After being notified of this delay time, the ONU adds the notified delay amount to the upstream data and transmits the data. As described above, the OLT measures the delay for the newly connected or activated ONU and notifies each ONU of the appropriate delay time, thereby efficiently realizing time division multiplexing transmission in the optical burst transmission / reception network. it can.

FIG. 8 is a block diagram of a general optical burst transmission / reception network (conventional system) for the OLT to perform delay measurement and bandwidth control from a plurality of ONUs and to transmit upstream data from each ONU to the OLT. Is. In the figure,
101 is an OLT, 102 is a main fiber, 103 is an optical splitter, 104a to 104n are branch fibers, and 105
a-105n have shown ONU. OLT101 is
It has an optical transceiver 1011, a maintenance signal transmission unit 1012, a band allocation unit 1013, an ONU management unit 1014, and a delay measurement unit 1015. The ONU 105a has an optical transmitter / receiver 105a1, a maintenance signal extraction unit 105a2, an allocation identification unit 105a3, a delay measurement cell generation unit 105a4, a delay addition unit 105a5, a buffer memory 105a6, a data reading unit 105a7, and a multiplexing unit 105a8. In the figure, in addition to 105a, ONUs 105b-O
Each ONU of the NU 105n is connected to each branch fiber 104a-1
04n connects to the optical splitter 103, and the optical splitter 103 is connected to the OLT by the trunk fiber 102.
101 connected to the OL through the optical splitter 103.
Communication is performed between the T101 and each of the ONUs 105a to 105n. Since the configuration of each ONU of the ONU 105b to ONU 105n is the same as that of the ONU 105a, the description of the internal configuration will be omitted.

Next, the operation of each constituent device will be described. In FIG. 8, the ONU management unit 10 in the OLT 101
14 manages registration and activation state of each ONU. For the registered ONUs, it is checked whether or not the delay measurement is completed. For the ONUs for which the delay measurement is not completed, a delay measurement instruction is issued at a certain fixed cycle by the bandwidth allocation unit 10.
Send to 13. The band allocation unit 1013 generates a non-allocation grant for performing delay measurement and a delay measurement grant for the ONU instructed by the ONU management unit 1014, and transmits the non-allocation grant and the delay measurement grant to the maintenance signal transmission unit 1012. The maintenance signal sending unit 1012 includes the sent grant value in the maintenance signal in a format that can be identified for each ONU, and sends the maintenance signal to the optical transceiver 1011. Here, which ONU is the maintenance signal
Whether or not the destination grant value is included is notified as a set of a predetermined ONU number and grant value. Optical transceiver 1011
Uses the sent maintenance signal as an optical signal for the main fiber 10
Send to 2. The sent optical signal is distributed to the branch fibers 104a to 104n by the optical splitter 103, and is sent to all the connected ONUs 105a to 105U.

The optical transceiver 105a1 in the ONU 105a, to which the maintenance signal is transmitted, converts the optical signal into an electric signal,
A maintenance signal is extracted by the maintenance signal extraction unit 105a2, and this maintenance signal is transmitted to the allocation identification unit 105a3 and the delay addition unit 105a5. Allocation identification unit 105a3
Retrieves and stores the above grant value associated with a predetermined own ONU number in the maintenance signal. The other ONUs 105b to 105n also similarly extract and store the grant values for themselves. If it is the delay measurement grant, the delay measurement cell generation unit 105a4 is instructed to generate a cell. Upon receiving the instruction, delay measurement cell generation section 105a4 generates a delay measurement cell and transmits it to multiplexing section 105a8. The multiplexing unit 105a8 sends a transmission electric signal to the optical transmitter / receiver 105a1, and the optical transmitter / receiver 105a1 converts the transmission electric signal into an optical signal, and then transmits the optical signal via the branch fiber 104a and the optical splitter 103.
An upstream optical signal is transmitted to the LT 101.

OLT 10 to which an upstream optical signal is transmitted
The optical transmitter / receiver 1011 in 1 converts the upstream optical signal from the ONU into an electrical signal and transmits the electrical signal to the delay measuring unit 1015. The delay measuring unit 1015 measures the time of the timing at which the delay measuring cell transmitted from the ONU is received from the generation timing of the delay measuring grant allocated by the band allocating unit 1013, and the measurement result is turned on.
It is transmitted to the management unit 1014. The ONU management unit 1014 calculates the additional delay time of the ONU based on this measurement result, and transmits it to the maintenance signal transmission unit 1012. The maintenance signal sending unit 1012 sends the maintenance signal to the ONU, including the additional delay time information in the maintenance signal. After that, the same processing as the above-described processing is performed, and the maintenance signal is extracted in the ONU 105a. However, this additional delay time information is notified to the delay adding section 105a5, and the delay adding section 105a5 records the additional delay time instructed by the data reading section 105a7 when it subsequently receives the grant and sends the data. The data read from the buffer memory 105a6 is instructed. The read additional delay time is notified to the multiplexing unit 105a8, subjected to delay processing, and then transmitted to the OLT 101 as an upstream optical signal by the optical transceiver 105a1.

As described above, in the conventional system shown in FIG. 8, the OLT 101 separately manages ONUs for which delay measurement has been completed and ONUs for which delay measurement has not been completed, and when performing delay measurement, grants of other ONUs are allocated. To generate an empty slot for delay measurement, after the delay measurement is completed, the ONU is notified of the additional delay time, and the ONU operates so as to add the additional delay time at the time of upstream data transmission. It realizes efficient use of the transmission line that shares the upstream transmission band and does not collide with data.

[0014]

However, in the system for performing delay measurement as described above, a delay measurement window (which is referred to as a ranging window in the above recommendation) is formed by consecutive non-allocation slots when the delay measurement is performed. However, there is a problem that it affects the signal traffic on the upstream side of the ONU that is already in operation. Specifically, when the delay measurement window is generated, the band allocation is stopped in all the ONUs, so that the traffic is forcibly lost and data that periodically transmits a signal is affected. Also, each ON
In order to guarantee the transmission band of U, the temporarily stopped band allocation is absorbed, so that it is necessary to increase and allocate the allocated slot for the stopped part after the delay measurement. If this increase allocation is not performed, the bandwidth will decrease each time delay measurement is performed. This increase can be absorbed by the difference between the originally allocated band while the delay measurement is not performed and the total band in the upstream direction.

For example, in the above ITU-T Recommendation,
The number of slots (cells) in one frame in the upstream direction is 53, but it is assumed that three devices of ONUa, ONUb, and ONUc are normally operating, and 41 slots are allocated to each frame in total, Considering the case where 36 slots of allocation to 3 devices are temporarily stopped by delay measurement, it is originally a surplus band of 53-41 = 12 slots per frame as seen from the maximum band, so the band lost during delay measurement is In order to compensate for the above, it is necessary to increase the slot allocation over at least 36/12 = 3 frames. The time until this compensation is completed is related to the size of the excess band, and is 12 slots per frame in the above example. If the excess band is small,
The influence on the traffic at the time of delay measurement is large, and when the surplus band is large, the influence on the traffic at the time of delay measurement becomes small.

FIG. 9 is a time chart showing a transmission delay of periodic data when delay measurement is performed in the conventional system shown in FIG. Now there is one ONU
It is assumed that the delay measurement is performed for another ONU when is in an operating state and periodic data is transmitted. Input of periodic data to ONU during operation is a1, a
2, a3, a4 have a fixed cycle, and the band allocation information from the OLT for the fixed cycle is also normally given. Here, when the delay measurement window is activated, the bandwidth information to be given during that period is stored in the OLT,
After the end of the delay measurement window, the band is read from the buffer memory, and the bands are allocated at the close intervals as shown in the read data column of FIG. At this time, the data a2 and a
For No. 3, delay fluctuations T2 and T3 occur respectively. Here, the delay fluctuation is the difference between the logical time of the transmission data when the fluctuation does not occur and the time of the actual transmission data. In this example, the difference T2 between the logical time for transmitting the data of a2 and the time when a2 is actually transmitted becomes the maximum fluctuation amount, T3 becomes smaller than T2, and the fluctuation disappears when transmitting a4. There is.

FIG. 10 shows the ONU in operation in FIG.
5 is a time chart showing a transmission delay of periodic data when the allocated bandwidth of is considered. In FIG. 9, O in operation
In the case where there is only one NU and the allocated bandwidths of other ONUs are not taken into consideration, in FIG. 10, there are a plurality of operating ONUs, the bandwidths allocated to those ONUs are taken into consideration, and delay measurement is similarly performed. We also consider the case where the vehicle is temporarily stopped by a window. Other O in the third row from the top of the figure
In the column of NU band allocation information (before delay addition), when the pulse is in the lower side (LOW), it means that the band is allocated to the assumed ONU and the pulse is in the upper side (HIG).
In the state of H), the band is allocated to another ONU.

Here, considering the operation of compensating for the band, the absorption of the delay fluctuation when transferring the data a1 to a6 becomes slower than in the case of FIG. In FIG. 10, the numerical value shown in the column of the number of allocated slots accumulated is the number of slots to be compensated at that time. In this case, since the bandwidth for 2 slots was not allocated in the delay measurement window portion, 2 was counted as a value to be compensated later, and after the delay measurement window was completed, additional allocation was made in addition to the normal band allocation timing. When this happens, this count will decrease. In both FIGS. 9 and 10, two slots are counted as a band to be compensated by the delay measurement window. In the example of FIG. 9, the delay fluctuation has already been eliminated at the time of data a4, whereas the example of FIG. Then, the fluctuation remains until the time of data a6. This difference is due to the size of the surplus band obtained by removing the bands allocated to all ONUs from the total upstream band after the end of the delay measurement window. That is, if the surplus band is large, the band that can be allocated to the band compensation after the delay measurement can also be increased, so that the delay fluctuation generated by the delay measurement can be quickly eliminated.

Further, the time interval for activating the delay measurement also affects the magnitude of the delay fluctuation and the time required to eliminate the fluctuation. FIG. 11 is a time chart showing a transmission delay of periodic data when the same bandwidth allocation and delay measurement window size as those in FIG. 10 are set and the activation intervals of two delay measurement windows are close to each other. By the way, the ITU-T Recommendation G. In 983.1, when measuring the delay for each ONU, 2
The delay measurement operation is performed twice, and when the difference between the two measurement results is within a certain value, the method ends normally.
Such an operation is actually performed. In this case, since the delay measurement window for the second time is activated before the influence of the delay fluctuation due to the delay measurement window for the first time is converged, the delay fluctuation is further increased as compared with the case of the single activation in FIG. There is.
Specifically, after the end of the first delay measurement window, the number of accumulated slots (bands requiring compensation) has decreased from 2 to 1, but the second delay measurement before reaching 0 Since the window is activated, the number of accumulated slots increases again, and becomes 3 at the end of the delay measurement window. As a result, it takes a long time to perform the allocation slot compensation process, and the delay fluctuation itself becomes large. Further, although not shown, the wider the delay measurement window, the larger the number of allocated slots to be stopped, so that the delay fluctuation becomes large and the time required for eliminating the delay fluctuation becomes long.

The ITU-T Recommendation G. In 983.1, the interval between the delay measurement windows shown above is not specified, and therefore the interval between the first and second delay measurement windows is not controlled. Therefore, according to the above-mentioned conventional technique, since the activation interval of the delay measurement window is constant regardless of the surplus band, when a large amount of band is allocated to the operating ONU, the data from the operating ONU is There was a problem that the influence on the delay fluctuation during execution of the delay measurement becomes large. Also,
Even when the delay measurement range is wide and therefore the size of the delay measurement window is large, there is a problem in that the influence of delay fluctuation becomes large as well.

The present invention has been made in view of the above,
To provide a delay measurement control method and apparatus for an optical burst transmission / reception network, which can reduce the influence on delay fluctuation of data at the time of delay measurement when bandwidth allocation to ONU is large or delay measurement time is long. To aim.

[0022]

In order to achieve the above object, a delay measurement control method for an optical burst transmission / reception network according to the present invention comprises a parent device sharing a transmission medium and a transmission path, and a plurality of child devices. The parent device comprises a step of measuring a transmission time according to a distance between the child device and the parent device, and a step of controlling allocation of a used band of the child device, wherein the child device allocates the used band. In a delay measurement control method for an optical burst transmission / reception network, comprising a step of transmitting a control-based transmission signal to the master device, the master device is configured to allocate bandwidth used to the slave device and / or a size of a delay measurement window. Based on the above, a step of controlling the activation interval of the delay measurement instruction is provided.

According to the present invention, the parent device is based on the allocation information of the used band to the child device, the size of the delay measurement window, or the allocation information of the used band to the child device and the size of the delay measurement window. It is possible to control the activation interval of the delay measurement instruction.

In the delay measurement control method in the optical burst transmission / reception network according to the next invention, the master device notifies the slave device of the delay addition time determined according to the transmission time measured for each slave device. Further comprising the step of: the slave device transmitting the transmission signal to the master device by adding the delay addition time different for each slave device to the transmission timing of the transmission signal based on the allocation control of the used band. Is further provided.

According to the present invention, the master device notifies the slave device of the delay addition time determined according to the transmission time measured for each slave device, and the slave device controls the allocation of the used band. The transmission signal can be transmitted to the parent device by adding a delay addition time different for each child device to the transmission timing of the base transmission signal.

In the delay measurement control method in the optical burst transmission / reception network according to the next invention, in the above invention, the allocation information of the used band to the child device is the band actually allocated to the child device by the parent device. And the sum of
It is characterized in that it is information on the difference from the maximum allocatable bandwidth.

According to the present invention, the parent device has information on the difference between the total bandwidth allocated to the child device by the parent device and the maximum allocatable bandwidth, the size of the delay measurement window,
Alternatively, the activation interval of the delay measurement instruction can be controlled based on the information on the difference between the total band allocated to the child device by the parent device and the maximum band that can be allocated and the size of the delay measurement window.

In the delay measurement control method in the optical burst transmission / reception network according to the next invention, in the above invention, the master device changes the size of the delay measurement window based on information on the delay measurement range for the slave device. The method further comprises the step of:

According to the present invention, the master device can change the size of the delay measurement window based on the information on the delay measurement range for the slave device.

A delay measurement control device in an optical burst transmission / reception network according to the next invention comprises a parent device sharing a transmission medium and a transmission path and a plurality of child devices, wherein the parent device is
A transmission signal based on the allocation control of the used band, comprising means for measuring a transmission time according to the distance between the child device and the parent device and means for controlling allocation of the used band of the child device. In the delay measurement control device of the optical burst transmission / reception network, which comprises means for transmitting the delay measurement to the parent device, the parent device measures the delay based on the allocation information of the used band to the child device and / or the size of the delay measurement window. It is characterized by comprising means for controlling the activation interval of the instruction.

According to the present invention, the parent device is based on the allocation information of the used band to the child device, the size of the delay measurement window, or the allocation information of the used band to the child device and the size of the delay measurement window. It is possible to control the activation interval of the delay measurement instruction.

In the delay measurement control device in the optical burst transmission / reception network according to the next invention, the master device notifies the slave device of the delay addition time determined according to the transmission time measured for each slave device. Means for transmitting the transmission signal to the parent device by adding the delay addition time different for each child device to the transmission timing of the transmission signal based on the allocation control of the used band. Is further provided.

According to the present invention, the master device notifies the slave device of the delay addition time determined according to the transmission time measured for each slave device, and the slave device controls the allocation of the used band. The transmission signal can be transmitted to the parent device by adding a delay addition time different for each child device to the transmission timing of the base transmission signal.

In the delay measurement control device in the optical burst transmission / reception network according to the next invention, in the above invention, the allocation information of the used band to the child device is the band actually allocated to the child device by the parent device. And the sum of
It is characterized in that it is information on the difference from the maximum allocatable bandwidth.

According to the present invention, the parent device has information on the difference between the total band allocated to the child device by the parent device and the maximum band that can be allocated, the size of the delay measurement window,
Alternatively, the activation interval of the delay measurement instruction can be controlled based on the information on the difference between the total band allocated to the child device by the parent device and the maximum band that can be allocated and the size of the delay measurement window.

In the delay measurement control device in the optical burst transmission / reception network according to the next invention, in the above invention, the master device changes the size of the delay measurement window based on information on the delay measurement range for the slave device. It is characterized by further comprising a means for doing.

According to the present invention, the master device can change the size of the delay measurement window based on the information on the delay measurement range for the slave device.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a delay measuring method and apparatus, an image display control method and the method in an optical burst transmission / reception network according to the present invention will be described below in detail with reference to the accompanying drawings.

Embodiment 1. FIG. 1 is a block diagram showing a configuration of a first embodiment to which a delay measurement control method for an optical burst transmission / reception network according to the present invention is applied. Compared with the conventional system of FIG. 8, the measurement control unit 1016 is added between the band allocation unit 1013 and the ONU management unit 1014. The other parts of the configuration are the same as those of the conventional system, and the same parts are designated by the same reference numerals. In the conventional system, the timing of the delay measurement activation instruction to the ONU in the OLT is performed at a constant cycle, but in the first embodiment, the bandwidth allocation unit 101 is used.
3 and the ONU management unit 1014, the measurement control unit 1016 can control the timing of this delay measurement activation instruction depending on the magnitude of the difference between the total band allocated after delay measurement and the total upstream band. .

Next, the operation of the system according to the first embodiment will be described. ONU management unit 101 in the OLT 101
4 manages registration and activation status of each ONU. For registered ONUs, it is checked whether delay measurement has been completed, and for ONUs for which delay measurement has not been completed,
The delay measurement instruction is transmitted to band allocation section 1013. The band allocation unit 1013 generates a non-allocation grant for performing delay measurement and a delay measurement grant for the ONU instructed by the ONU management unit 1014, and transmits the non-allocation grant and the delay measurement grant to the maintenance signal transmission unit 1012. Also, the total bandwidth allocated to each ONU is calculated and notified to the measurement control unit 1016. The measurement control unit 1016 calculates the size of the surplus band seen from the entire band in the upstream direction from this notified information, and determines the size of the surplus band and the size of the delay measurement window in the upstream data at the time of delay measurement. Of the delay measurement window is calculated and notified to the ONU management unit 1014 so that the influence on the delay fluctuation of the delay time becomes less than a desired value. The ONU management unit 1014 issues an ONU delay measurement instruction based on the activation interval information from the measurement control unit 1016 to the bandwidth allocation unit 1.
Send to 013. For other operations, see ONU
It is the same as the conventional system including the inside.

In the conventional system, when there is an ONU for which delay measurement has not been completed, the ONU management section 1014 sends a delay measurement instruction to the band allocation section 1013 at a certain fixed cycle. However, in the system according to the first embodiment, the ONU management unit 1014 uses the bandwidth allocation unit 1 based on the activation interval information transmitted from the measurement control unit 1016.
The delay measurement instruction is transmitted to 013.

By the way, in the system of the first embodiment,
From the allocation information transmitted from the band allocation unit 1013 to the measurement control unit 1016, the total band allocated to each ONU is clear. On the other hand, since we think that the delay measurement range is constant, the size of the delay measurement window is also constant,
From the total allocation to each ONU, the maximum number of slots that can be stopped when the delay measurement window is activated and the time required to compensate for them can be predicted. In this way, the measurement control unit 1016 sets the activation interval time so as to satisfy this time, and notifies the ONU management unit 1014 of the influence of the influence on the delay fluctuation of the upstream data.
As in the time chart of FIG. 10 described above, it is possible to limit the effect to when the delay measurement window is activated only once. If the activation time interval for delay measurement is not controlled, the influence on delay fluctuations may be accumulated as shown in the time chart of FIG. 11, and band compensation after delay measurement may become impossible. To be However, by controlling the activation time interval of the delay measurement, the delay fluctuation is resolved before the delay measurement windows for the second time and thereafter are activated, so the influence on the delay fluctuation does not accumulate. .

As described above, according to the first embodiment, the measurement control unit is added between the band allocation unit and the ONU management unit, and the ONU is based on the activation interval information from the measurement control unit.
Since the management unit transmits the delay measurement instruction to the band allocation unit, it is possible to suppress the influence on the delay fluctuation of the upstream data at the time of delay measurement, regardless of the allocated band amount for each ONU.

Embodiment 2. FIG. 2 is a block diagram showing the configuration of the second embodiment to which the delay measurement control method for an optical burst transmission / reception network according to the present invention is applied. The difference from the first embodiment of FIG. 1 is that a control signal is connected from the ONU management unit 1014 to the measurement control unit 1016. Other configurations are the same as those of the system of the first embodiment, and the same parts are denoted by the same reference numerals. While the system of the first embodiment has a function of controlling the delay measurement activation interval added to the conventional system, the system of the second embodiment further has a function of varying the size of the delay measurement window. It was done.

Next, the operation of the system according to the second embodiment will be described. The ONU management unit 1014, when the measurement range is known in advance for which ONU the delay measurement is to be performed, the ONU management unit 1014 obtains the information of the range by the band allocation unit 1
013 and the measurement control unit 1016 are notified. If there is no information on the measurement range, the ONU management unit 1014 does not notify the band allocation unit 1013 and the measurement control unit 1016 of the information on the measurement range, and therefore the same operation as that of the first embodiment is performed. On the other hand, when there is information on this measurement range, the bandwidth allocation unit 1013 issues a non-allocation grant corresponding to the number of slots narrowed down to that measurement range, and generates a delay measurement window. Further, the measurement control unit 1016 adjusts the influence on the delay fluctuation of the upstream data at the time of delay measurement to a desired value or less by the size of the surplus band and the size of the delay measurement window as in the first embodiment. , The activation interval of the delay measurement window is calculated from the information on the bandwidth allocation and the information on the measurement range, and the ONU management unit 1014 is notified of this. The other operations are the same as those in the first embodiment.

In the second embodiment, since the size of the delay measurement window changes, the effect on the delay fluctuation of the upstream data at the time of delay measurement also changes depending on the size. If there is no information on the delay measurement range, it is necessary to open the delay measurement window in the entire possible range, so that the activation interval is generally long and the time required to eliminate the delay fluctuation is also long. On the contrary, when there is information on the delay measurement range, the size of the delay measurement window can be made variable, so that the optimum delay measurement window can be set according to the position of the ONU to be measured, and the optimum delay measurement window can be set. Since the optimum activation interval of the delay measurement window can be set according to the window, the influence of delay fluctuation due to the delay measurement can be reduced.

FIG. 3 is a time chart showing the transmission delay of periodic data when the time of the delay measurement window is shortened and the activation interval of the delay measurement window is lengthened as compared with the condition of FIG. The conditions are the same as those in FIG. 11 except the size of the delay measurement window and the activation interval of the delay measurement window. 1st and 2
As can be seen from FIGS. 3 and 11, the required time for the second delay measurement is almost the same in both cases. However, in FIG. 11, the accumulated number of allocated slots increases and the delay fluctuation tends to increase, while in FIG.
Then, the accumulated number of allocated slots is 0 before the second delay measurement is started, and although not shown, delay fluctuation can be finally canceled.

As described above, according to the second embodiment, the measurement control unit is added between the band allocation unit and the ONU management unit, and the size of the delay measurement window is changed from the information of the measurement range.
Since the activation interval of the delay measurement window is controlled based on the bandwidth allocation information and the measurement range information, the effect on the delay fluctuation of the upstream data during delay measurement is suppressed regardless of the bandwidth allocated to each ONU. In addition, the delay measurement process can be speeded up according to the delay measurement range.

[0049]

As described above, according to the present invention, the parent device allocates the used band allocation information to the child device, the size of the delay measurement window, or the used band allocation information to the child device. Since the activation interval of the delay measurement instruction can be controlled based on the size of the delay measurement window, the influence on the delay fluctuation of the upstream data at the time of delay measurement can be suppressed regardless of the allocated bandwidth to the slave device. You can

According to the next invention, the master device notifies the slave device of the delay addition time determined according to the transmission time measured for each slave device, and the slave device controls the allocation of the used band. Since the transmission signal can be transmitted to the parent device by adding the delay addition time different for each child device to the transmission timing of the transmission signal based on the It is possible to suppress the influence on the delay fluctuation of data.

According to the next invention, the parent device has information on the difference between the total band allocated to the child device by the parent device and the maximum band that can be allocated, the size of the delay measurement window, or the parent device. Since it is possible to control the activation interval of the delay measurement instruction based on the information on the difference between the total bandwidth actually allocated to the child device by the device and the maximum assignable band and the size of the delay measurement window, the child device can be controlled. It is possible to suppress the influence on the delay fluctuation of the upstream data at the time of measuring the delay, regardless of the amount of allocated bandwidth to.

According to the next invention, since the master device can change the size of the delay measurement window based on the information on the delay measurement range for the slave device, the delay time can be adjusted regardless of the allocated bandwidth amount for the slave device. It is possible to suppress the influence on the delay fluctuation of the upstream data at the time of measurement, and it is possible to speed up the delay measurement process according to the delay measurement range.

According to the next invention, the parent device sets the allocation information of the used band to the child device, the size of the delay measurement window, or the allocation information of the used band to the child device and the size of the delay measurement window. Based on this, it is possible to control the activation interval of the delay measurement instruction, so that it is possible to suppress the influence on the delay fluctuation of the upstream data at the time of delay measurement, regardless of the amount of bandwidth allocated to the child device.

According to the next invention, the master device notifies the slave device of the delay addition time determined according to the transmission time measured for each slave device, and the slave device controls the allocation of the used band. Since the transmission signal can be transmitted to the parent device by adding the delay addition time different for each child device to the transmission timing of the transmission signal based on the It is possible to suppress the influence on the delay fluctuation of data.

According to the next invention, the parent device has information on the difference between the total band allocated to the child device by the parent device and the maximum band that can be allocated, the size of the delay measurement window, or the parent device. Since it is possible to control the activation interval of the delay measurement instruction based on the information on the difference between the total bandwidth actually allocated to the child device by the device and the maximum assignable band and the size of the delay measurement window, the child device can be controlled. It is possible to suppress the influence on the delay fluctuation of the upstream data at the time of measuring the delay, regardless of the amount of allocated bandwidth to.

According to the next invention, the parent device can change the size of the delay measurement window based on the information on the delay measurement range for the child device, so that the delay is not affected by the allocated bandwidth amount for the child device. It is possible to suppress the influence on the delay fluctuation of the upstream data at the time of measurement, and it is possible to speed up the delay measurement process according to the delay measurement range.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment to which a delay measurement control method for an optical burst transmission / reception network according to the present invention is applied.

FIG. 2 is a block diagram showing a configuration of a second embodiment to which a delay measurement control method for an optical burst transmission / reception network according to the present invention is applied.

FIG. 3 is a time chart showing a transmission delay of periodic data when the delay measurement window time is shortened and the delay measurement window activation interval is lengthened as compared with the condition of FIG. 11.

FIG. 4 ITU-T Recommendation G. 983.1, Figure 5 / G.
983.1-Generic physical configuration of the Optic
From the al Distribution Network, n ONUs (Optical
Network Unit) and one OLT (Optical Line Termin
ation) etc. is an explanatory diagram showing an optical burst transmission / reception network.

[Figure 5] ITU-T Recommendation Figure 11 / G.983.1-Frame
format for 155.52 / 155.52 Mbit / s O in PON
It is explanatory drawing which showed the data format of the direction from LT to ONU and the direction from ONU to OLT.

FIG. 6 is an OLT when delay control is normally performed.
It is explanatory drawing which showed the relationship of the distance and delay amount of (station side apparatus) and ONU (apparatus a, b, c).

FIG. 7 is an explanatory diagram showing a state of band control and delay control at the time when delay measurement is started.

FIG. 8: OLT performs delay measurement and bandwidth control from a plurality of ONUs, and upstream data from each ONU is OL
It is a block diagram of a general optical burst transmission / reception network (conventional system) for transmitting to T.

9 is a time chart showing a transmission delay of periodic data when delay measurement is performed in the conventional system shown in FIG.

FIG. 10 is a time chart showing a transmission delay of periodic data when the allocated band of the operating ONU in FIG. 9 is considered.

FIG. 11 is a time chart showing a transmission delay of periodic data when the activation intervals of two delay measurement windows are close to each other when the same bandwidth allocation and delay measurement window size as in FIG. 10 are provided.

[Explanation of symbols]

101 OLT, 102 trunk fiber, 103 optical splitter, 104a to 104n branch line fiber, 105
a to 105n ONU, 105a1 optical transceiver, 10
5a2 maintenance signal extraction unit, 105a3 allocation identification unit, 105a4 delay measurement cell generation unit, 105a5 delay addition unit, 105a6 buffer memory, 105a7 data reading unit, 105a8 multiplexing unit, 1011 optical transceiver, 1012 maintenance signal transmission unit, 1013 band allocation Section, 1014 ONU management section, 1015 delay measurement section, 1016 measurement control section.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroaki Mukai             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. F term (reference) 5K042 AA03 BA09 CA10 DA15 EA01                       JA01 MA02

Claims (8)

[Claims] 1. A master device that shares a transmission medium and a transmission path, and a plurality of slave devices, wherein the master device measures a transmission time according to a distance between the slave device and the master device, and In the delay measurement control method of the optical burst transmission / reception network, which comprises a step of controlling allocation of a use band of the slave device, wherein the slave device comprises a step of transmitting a transmission signal based on the allocation control of the use band to the master device, The delay of the optical burst transmission / reception network, characterized in that the master device controls the activation interval of the delay measurement instruction based on the allocation information of the band used for the slave device and / or the size of the delay measurement window. Measurement control method. 2. The parent device further comprises a step of notifying the child device of a delay addition time determined according to the transmission time measured for each of the child devices, and the child device is configured to use the used band. 2. The method according to claim 1, further comprising the step of adding the different delay addition time to each of the child devices to the transmission timing of the transmission signal based on the allocation control of transmitting the transmission signal to the parent device. Delay measurement control method for optical burst transceiver network. 3. The allocation information of the used band to the child device is information on a difference between a total band actually allocated to the child device by the parent device and a maximum allocatable band. The delay measurement control method for an optical burst transmission / reception network according to claim 1 or 2. 4. The parent device further comprises a step of varying a size of the delay measurement window based on information on a delay measurement range for the child device.
3. The delay measurement control method for an optical burst transmission / reception network according to any one of 3 above. 5. A parent device that shares a transmission medium and a transmission line, and a plurality of child devices, wherein the parent device measures a transmission time according to a distance between the child device and the parent device, and In the delay measurement control device of the optical burst transmission / reception network, which comprises means for controlling allocation of the used band of the slave device, wherein the slave device comprises means for transmitting a transmission signal based on the allocation control of the used band to the master device, The delay of the optical burst transmission / reception network, wherein the master device comprises means for controlling the activation interval of the delay measurement instruction based on the allocation information of the band used for the slave device and / or the size of the delay measurement window. Measurement control device. 6. The parent device further comprises means for notifying the child device of a delay addition time determined according to the transmission time measured for each of the child devices, and the child device is configured to use this used band. 6. The unit according to claim 5, further comprising means for adding the delay addition time different for each child device to the transmission timing of the transmission signal based on the allocation control of No. 1, and transmitting the transmission signal to the parent device. Optical burst transmission / reception network delay measurement controller. 7. The use band allocation information to the child device is information on a difference between a total band actually allocated to the child device by the parent device and a maximum allocatable band. The delay measurement control device for an optical burst transmission / reception network according to claim 5 or 6. 8. The parent device further comprises means for varying the size of the delay measurement window based on information on a delay measurement range for the child device.
7. A delay measurement control device for an optical burst transmission / reception network according to any one of 7.