JP2009111852A - Optical network unit, optical subscriber line terminal device and communication control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication control method for appropriately determining a communication condition of an ONU (optical network unit) connected to an optical network and controlling reboot of an OLT (optical line terminal). <P>SOLUTION: In communication between the OLT and the ONU, the communication control method controls a time of OLT reboot in accordance with the communication condition of the OLT or the ONU 2 connected to the OLT when the OLT disconnects the communication with the ONU 2 and reboots itself. The ONU 2 has at least one of a queue for temporarily storing data to be sent to the OLT by priority levels and a queue for temporarily storing data received from the OLT by priority levels, and also has a monitoring means for monitoring the presence or absence of data or a data quantity stored in the queues. The ONU 2 avoids reboot of the OLT when the ONU 2 determines that the data of a specific priority level is in the queue. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication control method in an optical access network, an optical subscriber line termination device (OLT) and an optical network termination device (ONU) to which the communication control method is applied.

  As shown in FIG. 1, the optical network includes one optical subscriber line terminal (OLT) 1 and one optical network terminal (ONU) 2 via an optical fiber transmission line. Point-to-point communication. The communication terminal 3 communicates with the OLT 1 via the ONU 2.

  In addition, as shown in FIG. 2, a passive optical network (PON) includes a single optical subscriber line terminator (OLT) 1 and a plurality of optical network terminators (ONU) 2-n and optical fiber transmission. In this method, point-to-multipoint communication is performed via a path and a 1 to k optical splitter 4 (n and k are natural numbers). One or more communication terminals 3-n communicate with the OLT 1 via the corresponding ONU 2-n. The following description will be given with OLT 1, ONU 2, and communication terminal 3 with typical reference numbers attached.

  One method of PON is TDMA-PON in which uplink data from ONU 2 to OLT 1 is multiplexed by time division multiple access (TDMA). In TDMA-PON, a plurality of ONUs 2 transmit signals to the OLT 1 using different time slots.

  In E-PON (Ethernet (registered trademark) -PON), which is a typical TDMA-PON standard, ONU 2 stores data transmitted from a communication terminal in a queue in ONU 2 during upstream communication. The amount of data stored in is reported to the OLT 1. Next, the ONU 2 transmits data for which transmission permission is obtained to the OLT 1 at the transmission start time designated by the OLT 1. Note that a report message from the ONU 2 to the OLT 1 and a transmission permission message from the OLT 1 to the ONU 2 are standardized by IEEE 802.3 as a REPORT message and a GATE message, respectively (for example, see Non-Patent Documents 1 and 2). Further, such a rule regarding point-to-multipoint communication between the OLT 1 and the ONU 2 is called MPCP (Multipoint Control Protocol).

  Further, in IEEE 802.3, a maintenance monitoring interface between the OLT 1 and the ONU 2 is defined as an OAM (Operation, Administration, and Maintenance) function. As one of the OAM functions, it is possible to prepare a command that causes the OLT 1 to restart the ONU 2. For example, when upgrading the firmware installed in the ONU 2 or when switching the line between the OLT 1 and the ONU 2, the ONU 2 needs to once disconnect from the OLT 1 and restart. Therefore, by using the OAM function, the OLT 1 transmits a restart command to the ONU 2 so that the restart of the ONU 2 can be realized. On the other hand, when upgrading the firmware installed in the OLT 1 or switching the line on the core network side from the OLT 1, the OLT 1 needs to temporarily disconnect the connection with the core network side device and restart it. . Note that both the OLT 1 and the ONU 2 also have an authentication function between the OLT 1 and the ONU 2.

  FIG. 3 shows a functional block diagram of a conventional optical subscriber line terminating device (OLT11). FIG. 4 shows a functional block diagram of a conventional optical network termination unit (ONU 22). In the conventional optical subscriber line terminating apparatus shown in FIG. 3, the downstream main signal is transmitted through the SNI (Service Node Interface) port 103, the bridge means 102, and the PON signal processing means 101 to the PON-IF (PON Interface) port 104. It flows to. On the other hand, the upstream main signal flows to the SNI port 103 via the PON-IF port 104, the PON signal processing means 101, and the bridge means 102.

  The OLT 11 includes a MAC control (MPCP) unit 105 that causes a conventional optical network termination unit (ONU 22) to report the amount of data in a queue provided in the ONU 22. Further, the MAC control unit 105 associates the bandwidth allocation calculated by the DBA unit 107 with each ONU 22. Further, the OLT 11 includes a DBA (Dynamic Bandwidth Assignment) unit 107 that calculates the allocation of the used bandwidth of each ONU 22 based on the report message received from the ONU 22, and a message monitoring unit 106 that monitors the data amount of the queue in the ONU 22. have.

  Furthermore, the OLT 11 includes an OAM signal processing unit 108 that realizes maintenance monitoring of a control frame for the ONU 22 and a reset unit 109 that restarts the OLT 11 by an external input. The PON signal processing unit 101 has a function of performing communication control by causing the MAC control unit 105 and the OAM signal processing unit 108 to function and processing an upstream main signal or a downstream main signal.

  In the conventional optical network terminator (ONU 22) shown in FIG. 4, the upstream main signal flows to the PON-IF port 204 via the UNI (User Network Interface) port 203, the bridge unit 202, and the PON signal processing unit 201. . On the other hand, the downstream main signal flows to the UNI port 203 via the PON-IF 204, the PON signal processing unit 201, and the bridge unit 202. The ONU 22 includes bridge means 202 having a plurality of queues for the upstream and downstream directions.

  The ONU 22 includes a queue (frame) monitoring unit 206 that monitors the amount of data in each queue, and a MAC control (MPCP) unit 205 that reports the amount of data in the queue of the ONU 22 to the OLT 11. Further, the ONU 22 has OAM signal processing means 208 that realizes control frame maintenance monitoring corresponding to the OAM signal processing means 108 of the OLT 11. The PON signal processing unit 201 has a function of performing communication control by causing the MAC control unit 205 and the OAM signal processing unit 208 to function, and processing an upstream main signal or a downstream main signal.

  At present, IETF (The Internet Engineering Task Force) standard RFC3550 is defined as a standard protocol for media transmission such as video or audio in an IP (Internet Protocol) network, and the communication quality in an IP network is defined by ITU-T. (International Telecommunication Union-Telecommunication Standardization Sector) Recommendation Y. As shown in 1541, the study of classifying continues.

T. Tatsuta et al. “Design philosophy and performance of a GE-PON system for mass deployment”, JOURNAL OF OPTICAL NETWORKING Vo. 6, No. 6, June 2007, p. 689-700 Technology Basic Course GE-PON Technology "4th GE-PON Systematization Function", NTT Access Service Systems Laboratories, NTT Technology Journal, Vol. 17, no. 11, November 2005, p. 59-61

  However, when the OLT 11 is disconnected once and restarted, the OLT 11 is restarted regardless of the communication state of the OLT 11 or the communication state of the ONU 22 connected to the OLT 11. There was a problem of loss of data.

  Accordingly, an object of the present invention is to provide a communication control method for appropriately determining the communication state of the OLT or ONU connected to the optical access network and controlling the restart of the OLT, and the OLT and ONU to which the communication control method is applied. There is to do.

  In order to solve the above-mentioned problem, when the OLT once cuts off the connection with the ONU and restarts, it monitors the communication state of the OLT or the communication state of the ONU connected to the OLT, and restarts the OLT. Control the time appropriately.

  Specifically, the OLT monitors the presence / absence of data in the transmission / reception queue in the OLT, the presence / absence of data in the transmission / reception queue in all ONUs connected to the OLT, or the priority of transmission / reception frames. Depending on the situation (for example, when data no longer exists in the queue), a mechanism for permitting restart of the OLT is provided.

That is, the optical network termination unit (ONU) of the present invention is
Means for monitoring the presence and / or amount of data in a queue for temporarily storing data to be transmitted and received;
When there is data in the queue, it is determined that an optical subscriber line terminating device (OLT) is communicating, and when there is no data or no longer exists in the queue, the OLT is not communicating. Means to judge,
It is characterized by providing.

The optical network termination unit (ONU) of the present invention is
Means for monitoring whether there is a transmission / reception of a data frame of a specific priority;
When there is a transmission / reception of a data frame with a specific priority, it is determined that the optical subscriber line termination device (OLT) is communicating, and transmission / reception of a data frame with a specific priority does not exist or no longer exists. A means for determining that the OLT is not communicating;
It is characterized by providing.

In the optical network termination unit (ONU) of the present invention,
The queue is a high priority queue among a plurality of queues having different priorities.

In the optical network termination unit (ONU) of the present invention,
The apparatus further comprises means for avoiding restart of the OLT when it is determined that the OLT is communicating, and for restarting the OLT when it is determined that the OLT is not communicating. .

Furthermore, the optical subscriber line termination device (OLT) of the present invention is
Means for monitoring the presence and / or amount of data in a queue for temporarily storing data to be transmitted and received;
Means for determining that communication is in progress when data is in the queue, and determining that communication is not in progress when data is not present or no longer exists in the queue;
It is characterized by providing.

The optical subscriber line termination device (OLT) of the present invention is
Means for monitoring whether there is a transmission / reception of a data frame of a specific priority;
If there is a transmission / reception of a data frame with a specific priority, it is determined that the communication is in progress. If transmission / reception of a data frame with a specific priority does not exist or no longer exists, it is determined that the communication is not in progress. Means,
It is characterized by providing.

The optical subscriber line termination device (OLT) of the present invention is
Means for monitoring the presence and / or amount of data stored in the queue of all optical network termination units (ONUs) connected to the optical subscriber line termination unit (OLT);
Means for determining that communication is in progress when data is present in at least one ONU queue, and determining that communication is not being performed when data is not present or no longer exists in all of the ONU queues When,
It is characterized by providing.

In the optical subscriber line terminating device (OLT) of the present invention,
The queue is a high priority queue among a plurality of queues having different priorities.

In the optical subscriber line terminating device (OLT) of the present invention,
The apparatus further includes a means for avoiding restart when it is determined that communication is in progress, and for restarting when it is determined that communication is not being performed.

Furthermore, the communication control method of the present invention includes:
In an optical network system that performs point-to-point or point-to-multipoint communication, when an optical subscriber line termination unit (OLT) once disconnects from the optical network termination unit (ONU) and restarts, the OLT Or a method of controlling the restart time of the OLT according to the communication state of the ONU connected to the OLT,
Each of the ONUs includes a first queue that temporarily stores data to be transmitted to the OLT for each priority, a second queue that temporarily stores data received from the OLT for each priority, and the first queue First monitoring means for monitoring the presence and / or amount of data in the queue and the second queue;
When each of the ONUs receives a reboot preparation command from the OLT,
Each processing procedure of the ONU is as follows:
Determining whether data of a specific priority is stored in the first queue and the second queue for a predetermined set time period by the first monitoring means;
A step of recognizing that the OLT cannot be restarted when the first monitoring means determines that at least one of the first queue and the second queue has data of a specific priority; and / or Responding to the OLT that restart preparation is not complete;
A step of recognizing that the OLT can be restarted when it is determined by the first monitoring means that data of a specific priority does not exist or no longer exists in both the first queue and the second queue; And / or responding to the OLT to be ready for rebooting, and
The OLT avoids restarting the OLT until receiving a response indicating that the restart preparation is complete from all of the ONUs,
Each of the ONUs controls a response indicating that the restart preparation is completed with respect to the OLT to avoid restart of the OLT.

Further, the communication control method of the present invention includes:
In an optical network system that performs point-to-point or point-to-multipoint communication, when an optical subscriber line termination unit (OLT) once disconnects from the optical network termination unit (ONU) and restarts, the OLT Or a method of controlling the restart time of the OLT according to the communication state of the ONU connected to the OLT,
Each of the ONUs includes first monitoring means for monitoring whether or not there is transmission / reception of a data frame having a specific priority,
When each of the ONUs receives a reboot preparation command from the OLT,
Each processing procedure of the ONU is as follows:
Determining whether or not there is a transmission / reception of a data frame of a specific priority by the first monitoring means for a predetermined set time period;
When the first monitoring means determines that a data frame with a specific priority is transmitted / received, the OLT recognizes that the OLT cannot be restarted and / or indicates that the restart preparation is not completed. A step of responding to
A step of recognizing that the OLT is in a restartable state and / or completion of restart preparation when it is determined by the first monitoring means that transmission / reception of a data frame of a specific priority does not exist or no longer exists Responding to the OLT,
The OLT avoids restarting the OLT until receiving a response indicating that the restart preparation is complete from all of the ONUs,
Each of the ONUs controls a response indicating that the restart preparation is completed with respect to the OLT to avoid restart of the OLT.

Further, the communication control method of the present invention includes:
In an optical network system that performs point-to-point or point-to-multipoint communication, when an optical subscriber line termination unit (OLT) once disconnects from the optical network termination unit (ONU) and restarts, the OLT Or a method of controlling the restart time of the OLT according to the communication state of the ONU connected to the OLT,
The OLT has a third queue for temporarily storing data to be transmitted to each of the ONUs for each priority, a fourth queue for temporarily storing data received from each of the ONUs for each priority, and Second monitoring means for monitoring the presence and / or amount of data in the third queue and the fourth queue;
The processing procedure of the OLT is as follows:
Determining whether or not data of a specific priority is stored in the third queue and the fourth queue for a predetermined set time period by the second monitoring means;
A step of restarting the OLT when the second monitoring means determines that data of a specific priority does not exist or no longer exists in both the third queue and the fourth queue;
It is characterized by including.

Further, the communication control method of the present invention includes:
In an optical network system that performs point-to-point or point-to-multipoint communication, when an optical subscriber line termination unit (OLT) once disconnects from the optical network termination unit (ONU) and restarts, the OLT Or a method of controlling the restart time of the OLT according to the communication state of the ONU connected to the OLT,
The OLT has second monitoring means for monitoring whether or not there is a transmission / reception of a data frame having a specific priority,
The processing procedure of the OLT is as follows:
Determining by the second monitoring means whether or not there is transmission / reception of a data frame of a specific priority for a predetermined set time period;
Performing a restart of the OLT when it is determined by the second monitoring means that transmission / reception of a data frame of a specific priority does not exist or no longer exists;
It is characterized by including.

In the communication control method of the present invention,
The ONU monitors a queue for temporarily storing data to be transmitted to the OLT and / or a queue for temporarily storing data received from the OLT, and reports the amount of data stored in the queue. Report to the OLT by a message.

In the communication control method of the present invention,
The queue is a high priority queue among a plurality of queues having different priorities.

Further, in the optical subscriber line terminating device (OLT) that is restarted by the communication control method of the present invention,
When all the ONUs connected to the OLT are disconnected once and restarted,
A function of transmitting a reboot preparation command to all ONUs connected to the OLT;
A function of receiving a response indicating completion of restart preparation or incomplete preparation of restart from all ONUs connected to the OLT;
When the restart preparation completion response is received from all ONUs connected to the OLT, the OLT is restarted.

Further, in the optical subscriber line terminating device (OLT) that is restarted by the communication control method of the present invention,
When all the ONUs connected to the OLT are disconnected once and restarted,
A function for transmitting an initialization command for initializing the internal state of the ONU to all the ONUs connected to the OLT, and for preventing the ONU from being newly authenticated before restarting;
A function of restarting the OLT when reception confirmation responses to the initialization command are received from all ONUs within a predetermined set time after transmitting the initialization command;
A function of transmitting an initialization command again to an ONU that has not responded when a reception confirmation response to the initialization command is not received from at least one ONU within a predetermined set time after the initialization command is transmitted; ,
It is characterized by providing.

Further, in the optical network termination unit (ONU) connected to the OLT that is restarted by the communication control method of the present invention,
Upon receipt of an initialization command received from the OLT for initializing the internal state of the ONU, a reception confirmation response to the initialization command is transmitted to the OLT and the internal state of the ONU is initialized. Function and
It is characterized by providing.

Further, in the optical subscriber line terminating device (OLT) that is restarted by the communication control method of the present invention,
A restart preparation command for preparing for the restart of the OLT is transmitted to all ONUs connected to the OLT, and the restart is performed from at least one ONU within a predetermined set time after the restart preparation command is transmitted. A function of transmitting a restart preparation command to an ONU that has not responded again when a preparation completion response or a restart preparation incomplete response has not been received;
When a restart preparation completion response is received from all ONUs within the predetermined set time, an initialization command for initializing the internal state of the ONU is transmitted to all ONUs and until the restart is performed. A new function not to authenticate the ONU;
If a restart preparation incomplete response is received from at least one ONU within the predetermined set time, a restart cancel command for canceling the restart preparation is transmitted to all ONUs to avoid restarting the OLT. Function to
A function of restarting the OLT when reception confirmation responses to the initialization command are received from all ONUs within a predetermined set time after transmitting the initialization command;
A function of transmitting an initialization command again to an ONU that has not responded when a reception confirmation response to the initialization command is not received from at least one ONU within a predetermined set time after the initialization command is transmitted; ,
If a restart cancel completion response is not received from at least one ONU within a predetermined set time after transmitting the restart cancel command, the restart cancel command is transmitted again to the ONU that has not responded. Function and
It is characterized by providing.

Further, in the optical network termination unit (ONU) connected to the OLT that is restarted by the communication control method of the present invention,
Monitoring the presence / absence of data stored in the first queue and the second queue or the priority of the data frame by receiving a restart preparation command for preparing the OLT to be restarted by the first monitoring unit When it is determined that there is data in the queue or a data frame of a specific priority is transmitted / received within a predetermined set time period after the monitoring is started, A function of transmitting a startup preparation incomplete response to the OLT to avoid restart of the OLT;
When it is determined that data does not exist or no longer exists in the first queue and the second queue within the predetermined set time period, or a data frame having a specific priority is not transmitted / received or is not transmitted / received A function to send a reboot preparation completion response to the OLT,
A function of discarding all data to be transmitted to the OLT and data received from the OLT within a predetermined set time period after transmitting the restart preparation completion response;
When an initialization command for initializing the ONU internal state is received from the OLT that has received the restart preparation completion response from all ONUs, a reception confirmation response to the initialization command is transmitted to the OLT. A function for initializing the internal state of the ONU;
When a restart cancellation command for canceling the restart preparation is received from the OLT within the predetermined set time period after transmitting the restart preparation completion response, a restart cancellation completion response is transmitted to the OLT. , The function to stop discarding of sent and received data,
When the initialization command or the restart cancellation command is not received within the predetermined set time after receiving the restart preparation command, or the initial setting within the predetermined set time after transmitting the restart preparation completion response. A function to stop discarding the data in the first queue and the second queue when the activation command or the restart cancellation command is not received;
It is characterized by providing.

Further, in the optical subscriber line terminating device (OLT) that is restarted by the communication control method of the present invention,
When a report message indicating that there is data in the queue of at least one ONU for a predetermined set time period after monitoring of the report messages received from all ONUs connected to the OLT is started, A function of avoiding restart of the OLT;
A function for restarting the OLT when receiving a report message indicating that no data exists or no longer exists in the queues of all ONUs during the predetermined set time;
It is characterized by providing.

Further, in the optical subscriber line terminating device (OLT) that is restarted by the communication control method of the present invention,
At least one period of a predetermined set time from the start of monitoring of report messages received from all ONUs connected to the OLT and monitoring of the priority of data or data frames stored in the queue of the OLT When a report message indicating that there is data in one ONU queue is received, or when it is determined that there is data in the OLT queue, or when it is determined that a data frame of a specific priority is transmitted / received, A function of avoiding restart of the OLT;
When a report message indicating that no data exists or no longer exists in all ONU queues during the predetermined set time period and when it is determined that no data exists or no longer exists in the OLT queue Or a function to restart the OLT when it is determined that a data frame having a specific priority is not transmitted or received, or is no longer transmitted or received;
It is characterized by providing.

Further, in the optical subscriber line terminating device (OLT) that is restarted by the communication control method of the present invention,
A function of transmitting a restart preparation command for preparing for the restart of the OLT to all ONUs connected to the OLT;
A function of transmitting a restart preparation command again to an ONU that has not responded when a restart preparation completion response is not received from at least one ONU within a predetermined set time after the restart preparation command is transmitted When,
A function for starting monitoring of report messages received from all ONUs connected to the OLT when a response to completion of restart preparation is received from all ONUs within the predetermined set time;
When a report message indicating that no data exists or no longer exists in the queues of all ONUs for a predetermined set time period after the start of monitoring is used to initialize the internal state of the ONUs A function to send an initialization command to all ONUs and not to newly authenticate an ONU until a restart is performed;
A function for restarting the OLT when reception confirmation responses to the initialization command are received from all ONUs within a predetermined set time after transmitting the initialization command;
A function of transmitting an initialization command to an ONU that has not responded again when a reception confirmation response to the initialization command is not received from at least one ONU within the predetermined set time;
Restart for canceling the restart preparation when a report message indicating that there is data in the queue of at least one ONU is received during the predetermined set time period in which monitoring of report messages received from all ONUs is started. A function of sending a cancel command to all ONUs to avoid restart of the OLT;
A function of transmitting a restart cancellation command to an ONU which has not responded again when a restart cancellation completion response is not received from at least one ONU within a predetermined set time after transmitting the restart cancellation command. When,
It is characterized by providing.

Further, in the optical subscriber line terminating device (OLT) that is restarted by the communication control method of the present invention,
A function of transmitting a restart preparation command for preparing for restart of the OLT to all ONUs connected to the OLT;
A function of transmitting a restart preparation command again to an ONU that has not responded when a restart preparation completion response is not received from at least one ONU within a predetermined set time after the restart preparation command is transmitted When,
If a response to completion of restart preparation is received from all ONUs within the predetermined set time, monitoring of report messages received from all ONUs connected to the OLT and storing them in the queue of the OLT A function to start monitoring data or data frame priority;
When a report message indicating that data does not exist or no longer exists in all ONU queues for a predetermined set time period after the start of the monitoring, and a data frame having a specific priority in the OLT When the transmission / reception is not performed or is not performed, the initialization command for initializing the internal state of the ONU is transmitted to all ONUs, and new ONU authentication is not performed until restarting. Function to
When a report message indicating that data exists in the queue of at least one ONU is received during the predetermined set time period, or when it is determined that a data frame having a specific priority is transmitted / received in the OLT A function of sending a restart cancel command for canceling restart preparation to all ONUs to avoid restart of the OLT;
A function for restarting the OLT when reception confirmation responses to the initialization command are received from all ONUs within a predetermined set time after transmitting the initialization command;
A function of transmitting an initialization command to an ONU that has not responded again when a reception confirmation response to the initialization command is not received from at least one ONU within the predetermined set time;
A function of transmitting a restart cancellation command to an ONU which has not responded again when a restart cancellation completion response is not received from at least one ONU within a predetermined set time after transmitting the restart cancellation command. When,
It is characterized by providing.

Further, in the optical network termination unit (ONU) connected to the OLT that is restarted by the communication control method of the present invention,
A function of transmitting a restart preparation completion response to the OLT in response to reception of a restart preparation command for preparing for the restart of the OLT;
After transmission of the restart preparation completion response, monitoring of the presence / absence or amount of data stored in the queue of the ONU, or monitoring of the priority of the data frame is started, and a predetermined set time after starting the monitoring If it is determined that there is data in the ONU queue during this period, or if it is determined that a data frame of a specific priority has been transmitted / received, a report message to that effect is transmitted to the OLT and the OLT The ability to avoid restarts,
In the monitoring, when it is determined that data does not exist or no longer exists in the queue of the ONU, or when it is determined that a data frame of a specific priority is not transmitted / received or is no longer transmitted / received, A function of discarding all data to be transmitted to the OLT and data received from the OLT in the ONU queue during a predetermined set time period;
Upon receipt of an initialization command received from the OLT for initializing the internal state of the ONU, a reception confirmation response to the initialization command is transmitted to the OLT and the internal state of the ONU is initialized. Function and
If a restart cancel command for canceling the restart preparation is received from the OLT within a predetermined set time period after the monitoring, a restart cancel completion response is transmitted to the OLT and the transmission / reception data is discarded. With the ability to stop
When the initialization command or the restart cancellation command is not received within the predetermined set time after receiving the restart preparation command, or within the predetermined set time after monitoring the ONU queue Alternatively, it has a function of stopping the discarding of data in the first queue and the second queue when a restart cancellation command is not received.

  According to the present invention, during the OLT communication or the ONU communication connected to the OLT (especially during the communication of a high priority service), the execution of the OLT restart is suppressed, and the effective data Loss and interruption of communication can be prevented in advance.

  First, functional blocks of an optical subscriber line termination unit (OLT) and an optical network termination unit (ONU) according to the present invention will be described. It should be noted that the same constituent elements will be described with the same reference numerals.

FIG. 5 shows a functional block diagram of an optical subscriber line terminating device (OLT) according to the present invention.
The OLT 1 according to the present invention includes a PON signal processing unit 101, a bridge unit 102, an SNI port 103, a PON-IF port 104, a MAC control unit 105, a message monitoring unit 106, a DBA unit 107, an OAM signal processing unit 108, and a reset / blocking unit. 110, a restart determination unit 111 and a queue (frame) monitoring unit 112.

  Compared with the conventional OLT 11 (see FIG. 3), in particular, the reset / blocking means 110, the restart determination means 111, and the queue (frame) monitoring means 112 are further provided, and the data received from the ONU 2 in the bridge means 102 Is different in that a queue for temporarily storing data for each priority level and a queue for temporarily storing data to be transmitted to the ONU 2 for each priority level are set. Realize control.

  That is, the PON signal processing unit 101 has a function of controlling the uplink main signal or the downlink main signal by causing the MAC control unit 105 and the OAM signal processing unit 108 to function and performing communication control. In the case of a point-to-point optical network, this PON signal processing means 101 is referred to as a signal processing means 101.

  The bridge unit 102 is configured to have a plurality of queues for temporarily storing data in each of the upstream direction and the downstream direction.

  The MAC control unit 105 manages the MAC address in communication with the ONU 2, causes the ONU 2 to report the amount of data in the queue provided in the ONU 2 and the priority of the data frame, and also calculates by the DBA unit 107. The used bandwidth allocation is associated with each ONU 2. Further, a discovery process is executed for each ONU 2 after the OLT 1 is restarted.

  The message monitoring means 106 monitors the report message from each ONU 2 acquired via the MAC control means 105 and sends the data amount in the queue of the ONU 2 and the priority of the data frame to the DBA means 107, and also according to the present invention. Also sent to the restart determination means 111 for determination of restart of the OLT 1.

  The DBA unit 107 calculates the allocation of the used bandwidth of each ONU 2 based on the queue data amount in the ONU 2 acquired through the MAC control unit 105, and sends the calculation result to the MAC control unit 105.

  The OAM signal processing means 108 mainly realizes maintenance monitoring of the control frame for the ONU 2. In the present invention, in particular, the OAM signal processing means 108 issues a restart preparation command for causing each ONU 2 to prepare for restart, and an initialization command for initializing each ONU 2 (or a discard command for discarding data). It has a function to generate. The OAM signal processing means 108 has a function of processing a response to a restart preparation command or an initialization command (or a discard command) from each ONU 2 and retransmitting the command to the ONU 2 when there is no response. It has a function of sending the content of the response to the restart determination unit 111.

  Based on the determination result of the restart determination unit 111, the reset / blocking unit 110 receives an external input if all the ONUs 2 connected to the OLT 1 can be restarted or the OLT 1 can be restarted. Permits the restart of OLT1. Note that the reset / blocking unit 110 may be configured to automatically restart the OLT 1 when all the ONUs 2 are in a restartable state or the OLT 1 is in a restartable state. The reset / blocking unit 110 has a function of discarding all data transmitted to the ONU 2 and data received from the ONU 2 and a function of blocking an interface with the ONU 2.

  The restart determination unit 111 has one or a plurality of timers for controlling the time at which the OLT 1 is restarted. The queue data amount in all the ONUs 2 connected to the OLT 1, the queue data amount in the OLT 1, In addition, it has a function of grasping the priority of transmission / reception frames and performing a restart determination as to whether or not to restart the OLT 1. A plurality of set times such as a period for monitoring data in the transmission / reception queue in the OLT 1 or a period for monitoring the priority of transmission / reception frames are set in the timer. As will be apparent from the embodiments described later, the plurality of set times can include those that constrain the processing time on the ONU 2 side, and the set times that should be set on the ONU 2 side can also be managed. The set time set on the ONU 2 side may be configured to be included in the transmission permission message, the restart preparation command, or the initialization command. In the case of a point-to-point optical network, the restart determination unit 111 can acquire information on the data amount in the queue of the ONU 2 directly from the signal processing unit 101.

  The queue (frame) monitoring unit 112 determines the priority of a data frame to be transmitted / received, for example, a CoS (Class of Service) value stored in a VLAN tag header of the data frame or a ToS (Type) stored in an IP header. of Service) has a function of identifying and monitoring the priority based on the value and a function of monitoring the presence or amount of data in each queue in the bridge unit 102, and sends each monitoring result to the restart determination unit 111.

  FIG. 6 shows a functional block diagram of an optical network termination unit (ONU) according to the present invention. The ONU 2 according to the present invention includes a PON signal processing unit 201, a bridge unit 202, a UNI port 203, a PON-IF port 204, a MAC control unit 205, a queue (frame) monitoring unit 206, an OAM signal processing unit 208, and a block / initialization unit. 210 and a restart determination unit 211.

  Compared with the conventional ONU 2 (refer to FIG. 4), it is different in that it further includes a blocking / initializing means 210 and a restart determining means 211, thereby realizing control of the restart time of the OLT 1. .

  That is, the PON signal processing unit 201 has a function of controlling the uplink main signal or the downlink main signal by causing the MAC control unit 205 and the OAM signal processing unit 208 to function and performing communication control. In the case of a point-to-point optical network, this PON signal processing means 201 is referred to as a signal processing means 201.

  The bridge means 202 is configured to have a plurality of queues for temporarily storing data in each of the upstream direction and the downstream direction.

  The MAC control unit 205 has a function of managing the MAC address in communication with the OLT 1 and reporting the amount of data in the queue provided in the ONU 2 and the priority of the data frame to the OLT 1. In addition, it waits until the discovery process is executed after the OLT 1 is restarted.

  The queue (frame) monitoring unit 206 has a function of identifying and managing the priority of the data frame by, for example, the CoS value stored in the VLAN tag header of the data frame or the ToS value stored in the IP header, and The bridge unit 202 has a function of monitoring the presence or amount of data in each queue, and sends each monitoring result to the restart determination unit 211.

The OAM signal processing means 208 mainly implements control frame maintenance monitoring for the OLT 1. In the present invention, in particular, the OAM signal processing unit 208 processes the restart preparation command or initialization command (or discard command) transmitted from the OLT 1 and associates the determination result from the restart determination unit 211 with respect to each command. Has the function of generating a response. The OAM signal processing unit 208 has a function of controlling responses to each command based on a set time set for monitoring data in the transmission / reception queue in the ONU 2 or monitoring priority of transmission / reception frames.
When the OAM signal processing unit 208 receives an initialization command (or discard command) for initializing the internal state of the ONU 2 from the OLT 1, the OAM signal processing unit 208 extracts the initialization command or the discard command via the PON signal processing unit 201. The fact that the initialization or discarding process is executed is sent to the closing / initializing means 210. Note that the plurality of set times may be determined in advance according to a command from the OLT 1 and the restart determination unit 211 may manage the plurality of set times.

  The blocking / initializing unit 210 has a function of placing the ONU 2 in an executable state or automatically initializing it based on the initialization command or the discard command received from the OAM signal processing unit 208. Further, the block / initialization unit 210 has a function of discarding all data transmitted to the OLT 1 and data received from the OLT 1 based on the initialization command or the discard command received from the OAM signal processing unit 208, and the OLT 1 Has the function of closing the interface.

The restart determination unit 211 includes one or more timers for controlling time used for determining whether or not to restart the OLT 1. The restart determination unit 211 grasps the data amount of the queue and the priority of the transmission / reception data frame in the ONU 2 based on the monitoring result by the queue (frame) monitoring unit 206, and determines whether or not the OLT 1 can be restarted. Has a function of performing such a restart determination and sending the determination result to the OAM signal processing means 208 or the block / initialization means 210.
A plurality of set times such as a period for monitoring data in the transmission / reception queue in the ONU 2, a period for monitoring the priority of transmission / reception frames, or a response period for each command are set in the above-described timer. The setting time to be set on the ONU 2 side can also be managed on the OLT 1 side. For example, the setting time to be set on the ONU 2 side can be set on the OLT 1 side by a transmission permission message, a restart preparation command, or initialization. It can also be included in the command.

  The OLT 1 and the ONU 2 may include separate means for monitoring the priority of the uplink or downlink data, instead of providing a plurality of queues for the uplink or downlink directions.

  A communication control method according to a first embodiment of an optical subscriber line terminating device (OLT) and an optical subscriber line terminating device (OLT) according to the present invention will be described below with reference to the drawings.

(Example 1)
FIG. 7 is a sequence diagram showing a communication control method according to the first embodiment of the present invention. In the communication control method of the first embodiment, the optical subscriber line terminating device (OLT1) monitors the queue in the OLT1, and the OLT1 autonomously controls the restart time of the OLT1. In FIG. 7, as an example, three optical network terminators (ONU-1, ONU-2, and ONU-3) are represented with respect to one optical subscriber line terminator (OLT), and will be described as ONU2 if not specified. ) Indicates the case of connection.

  Further, the optical subscriber line terminating device (OLT1) and the optical network terminating device (ONU-1, ONU-2, and ONU-3) according to the present invention can be realized by the configurations shown in FIGS. 5 and 6, respectively. In the case of a point-to-point optical network, the OLT 1 may be configured such that the MAC control means 105, the message monitoring means 106, and the DBA means 107 are unnecessary, and the ONU 2 does not require the MAC control means 205. You may comprise as follows. Furthermore, in the case of a point-to-point optical network, the PON signal processing means 101 and 201 shown in FIGS. 5 and 6 are configured as signal processing means for an optical network that function similarly in the operation of the first embodiment.

  First, the OLT 1 starts monitoring the data stored in the queue of the bridge unit 102 included in the OLT 1 by the queue (frame) monitoring unit 112. When the queue (frame) monitoring unit 112 determines that data does not exist or no longer exists in the queue in the OLT 1 during the first set time ST1 set by the restart determination unit 111, the OLT 1 111 is judged to be in a restartable state, and an initialization command for initializing the internal state of the ONU 2 is transmitted by the OAM signal processing means 108 to all the ONUs 2 connected to the OLT 1, and the reset / blocking means 110 performs the OLT 1 The ONU 2 is not newly authenticated until the restart.

  In step S11, the OLT 1 transmits the initialization command generated by the OAM signal processing unit 108 to all the ONUs 2, and transmits it to the ONU 2 by the reset / blocking unit 110 during the second set time ST2 after the initialization command is transmitted. All data received and data received from the ONU 2 are discarded.

  In step S12, each ONU 2 that has received the initialization command transmits a reception confirmation response to the initialization command generated by the OAM signal processing means 208 to the OLT 1 and initializes the internal state of the ONU 2 by the blocking / initialization means 210. Then, after the OLT 1 is restarted, it waits until a discovery process is executed.

  In step S <b> 13, the OLT 1 that has received the reception confirmation response to the initialization command from all the ONUs 2 connected to the OLT 1 restarts the OLT by the reset / blocking unit 110.

  In step S14, after the OLT 1 is restarted, the MAC control unit 105 executes a discovery process.

  Next, when the OLT 1 starts monitoring the queue and the queue (frame) monitoring unit 112 determines that data exists in the queue in the OLT 1 during the first set time ST1, the OLT 1 uses the restart determination unit 111. It is determined that the restart is impossible, and the restart of the OLT is avoided (that is, the initialization operation by the reset / blocking unit 110 is not executed).

  If the OLT 1 does not receive a reception confirmation response to the initialization command from the at least one ONU 2 connected to the OLT 1 within the second set time ST2 after the initialization command is transmitted, the OLT 1 receives the initialization command. Therefore, the OAM signal processing means 108 retransmits the initialization command to the ONU 2 that has not responded.

  Here, a value larger than the transmission / reception interval of the data frames stored in the queue is set as the first set time ST1.

  With respect to the value of the first set time ST1 to be monitored for this frame, in order to avoid restart of the OLT 1 during execution of the telephone application using SIP, the OLT 1 queues a queue for temporarily storing data received from the ONU 2 ( The case of monitoring by the frame) monitoring means 112 will be described.

  In IETF standard RFC3550, it is recommended that the transmission interval of voice packets (RTP packets) be 20 milliseconds, and the first determination time ST1 is set to at least 20 milliseconds or more by the restart determination unit 111. For example, if the first set time ST1 is set to 50 times the transmission interval, that is, 1 second or less, a plurality of frames can be monitored.

  Next, with respect to the value of the first set time ST1, a queue for temporarily storing data to be transmitted to the ONU 2 by the OLT 1 is queued (frame) in order to avoid restart of the OLT 1 during execution of the telephone application using SIP. The case where monitoring is performed by the monitoring unit 112 will be described.

Even if the voice packet is transmitted from the terminal device on the transmission side at an interval of exactly 20 milliseconds, the voice packet cannot be received at regular intervals due to the influence of packet loss and delay fluctuation until it is received by the OLT 1. There is a case. ITU-T Y.M. When voice packets are transmitted and received with Class 0 communication quality defined in 1541, the packet loss rate is 10 ⁻³ or less and the packet delay fluctuation is 50 milliseconds or less. For example, even if delay fluctuation of a maximum of 50 milliseconds is taken into account, if the first set time ST1 is set to 70 milliseconds or more, at least one frame can be monitored. If the first set time ST1 is set to 50 times the transmission interval, that is, 1 second or less, 47 frames can be monitored at maximum. When the first set time ST1 is set to 1 second, the probability that a voice packet is not observed during monitoring is (10 ⁻³ ) ⁴⁷ = 10 ⁻¹⁴¹ .

  Also, the first set time ST1 is set to a value larger than the time-out time from when the INVITE message for establishing the SIP session is transmitted until the 200 OK message (that is, the request success message) is received. Thus, in addition to avoiding restart of the OLT 1 during execution of the telephone application, restart of the OLT 1 in the SIP session establishment phase can be avoided.

  For the second set time ST2, a value larger than the round trip time between the OLT 1 and the ONU 2 is set. The second set time can be arbitrarily set as a relative time according to the installation distance to each ONU 2 and is managed by the OLT 1.

  The OLT 1 may monitor the priority of data frames to be transmitted / received instead of monitoring the data stored in the queue in the OLT 1. In other words, the queue (frame) monitoring unit 112 monitors the priority of the data frame transmitted to the ONU 2, monitors the priority of the data frame received from the ONU 2, or both, thereby setting a specific priority. You can grasp the communication status of your application.

  For example, when it is determined that a data frame having a specific priority is not transmitted or received during the first set time ST1 after the OLT 1 starts monitoring, the OLT 1 determines that the data frame can be restarted, and the OLT 1 Restart. Further, when a data frame having a specific priority is transmitted / received during the first set time ST1 after the OLT 1 starts monitoring, the OLT 1 determines that it cannot be restarted and avoids restarting the OLT 1 To do.

  The priority of the data frame is identified by the CoS value stored in the VLAN tag header of the data frame or the ToS value stored in the IP header. Monitoring of data in the queue may be performed based on a specific priority.

  Instead of providing a function for the OLT 1 to send an initialization command for initializing the internal state of the ONU 2 to the ONU 2, if the ONU 2 has not received a message from the OLT 1 for a certain period of time, it is determined that the OLT 1 has been restarted Then, the ONU 2 may have a function of autonomously initializing the internal state and performing a discovery process.

  As described above, according to the communication control method of the first embodiment of the present invention, the OLT 1 can monitor the queue in the OLT 2 and the OLT 1 can autonomously control the restart time of the OLT 1.

  Next, a communication control method according to the second embodiment in the optical subscriber line terminating device (OLT) and the optical subscriber line terminating device (OLT) according to the present invention will be described with reference to the drawings.

(Example 2)
8 and 9 are sequence diagrams showing a communication control method according to the second embodiment of the present invention. In the communication control method according to the second embodiment illustrated in FIGS. 8 and 9, each ONU 2 that has received an instruction to prepare for restart from the OLT 1 monitors the queue in the ONU 2, and the OLT 1 is based on the monitoring result of the queue in the ONU 2. Control the restart time of. FIG. 8 shows an example when the restart is successful, and FIG. 9 shows an example when the restart fails. In FIG. 8 and FIG. 9, as an example, three optical network terminators (ONU-1, ONU-2 and ONU-3) are represented for one optical subscriber line terminator (OLT). Is described as being connected).

  Further, the optical subscriber line terminating device (OLT1) and the optical network terminating device (ONU-1, ONU-2, and ONU-3) according to the present invention can be realized by the configurations shown in FIGS. 5 and 6, respectively. In the case of a point-to-point optical network, the OLT 1 may be configured such that the MAC control means 105, the message monitoring means 106, and the DBA means 107 are unnecessary, and the ONU 2 does not require the MAC control means 205. You may comprise as follows. Furthermore, in the case of a point-to-point optical network, the PON signal processing means 101 and 201 shown in FIGS. 5 and 6 are configured as signal processing means for an optical network that function similarly in the operation of the second embodiment.

  First, in step 21, the OLT 1 transmits a restart preparation command for preparing for the restart of the OLT 1 to all the ONUs 2 connected to the OLT 1 by the OAM signal processing means 108. The ONU 2 that has received the restart preparation command starts monitoring the data stored in the queue provided in the ONU 2 by the queue (frame) monitoring means 206.

  As shown in FIG. 8, after receiving the restart preparation command, each ONU 2 determines that data is not present or no longer exists in the queue by the queue (frame) monitoring means 206 during the sixth set time ST6. In this case, the restart determination unit 211 determines that the ONU 2 is in a restartable state, and the OAM signal processing unit 208 transmits a restart preparation completion response to the OLT 1 (step S22). Further, each ONU 2 transmits a restart preparation completion response to the OLT 1, and transmits it to the OLT 1 by the blocking / initializing means 210 so that a new session is not established through the ONU 2 during the seventh set time ST 7. All data and data received from OLT 1 are discarded.

  On the other hand, as shown in FIG. 9, when each ONU 2 starts monitoring the queue, the queue (frame) monitoring means 206 has data in the queue in each ONU 2 during the sixth set time ST6. If it is determined, the ONU 2 determines that the restart is not possible by the restart determination unit 211 and transmits a restart preparation end completion response to the OLT 1 by the OAM signal processing unit 208 in order to avoid restart of the OLT 1. . This is because the OLT 1 can restart the OLT 1 after receiving the restart preparation completion responses from all the ONUs 2.

  The example of FIG. 9 shows a case where the ONU-1 determines that data exists in the queue in the ONU-1, and the ONU-1 transmits a restart preparation incomplete response to the OLT1. Therefore (step S22 in the ONU-1 in FIG. 9), the restart of the OLT 1 can be avoided.

  Next, as shown in FIG. 8, in step S23, the OLT 1 that has received the restart preparation completion response from all the ONUs 2 connected to the OLT 1 is determined by the restart determination unit 111 to be in a restartable state. The OAM signal processing means 108 transmits an initialization command for initializing the ONU 2 state to all ONUs 2 connected to the OLT 1, and the reset / blocking means 110 newly authenticates the ONU 2 until the OLT 1 is restarted. Do not.

  In step S24, each ONU 2 that has received the initialization command transmits a reception confirmation response to the initialization command generated by the OAM signal processing means 108 to the OLT 1, and the blocking / initializing means 210 initializes the internal state of the ONU 2. Then, after the OLT 1 is restarted, it waits until a discovery process is executed.

  In step S25, the OLT 1 that has received the reception confirmation response to the initialization command from all ONUs 2 connected to the OLT 1 restarts the OLT 1 by the reset / blocking means 110.

  On the other hand, as shown in FIG. 9, in step S27, the OLT 1 that has received the restart preparation incomplete response from at least one ONU 2 connected to the OLT 1 is determined by the restart determination unit 111 to be in a state in which it cannot be restarted. Then, the OAM signal processing means 108 transmits a restart cancel command for canceling the preparation for restarting the ONU 2 to all ONUs 2 connected to the OLT 1 to avoid restart of the OLT 1 (that is, by the reset / blocking means 110). Do not perform initialization operation).

  In step S28, each ONU 2 that has received the restart cancellation command transmits a restart cancellation completion response to the OLT 1 by the OAM signal processing unit 208, and stops the discarding of transmission / reception data by the reset / blocking unit 110.

  When the OLT 1 does not receive the restart preparation completion response or the restart preparation incomplete response from the at least one ONU 2 within the third set time ST3 after the OLT 1 transmits the restart preparation command, the OLT 1 performs the OAM signal processing unit 108. Thus, it is determined that the restart preparation command has not arrived at the ONU 2 that has not responded, and the restart preparation command is retransmitted to the ONU 2 that has not responded.

  Further, within 4th set time ST4 after the OLT 1 sends the initialization command, or within 5th set time after sending the restart cancellation command, a reception confirmation response or restart cancellation completion response from at least one ONU 2 Is not received by the OAM signal processing means 108, the OLT signal processing means 108 determines that the initialization command or restart cancel command has not arrived at the unresponsive ONU 2, and responds with an initialization command or restart cancel command. Retransmit to ONU2 where there was no.

  In this embodiment, each ONU 2 makes a response for completion of restart preparation and starts discarding the transmission / reception data in the queue in the ONU 2. Therefore, each ONU 2 does not receive the initialization command within the eighth set time ST8 after receiving the restart preparation command, or within the seventh set time ST7 after transmitting the restart preparation completion response. When the initialization command is not received, the discarding of transmission / reception data is stopped. Each ONU 2 does not receive the restart cancellation command within the eighth set time ST8 after receiving the restart preparation command, or within the seventh set time ST7 after transmitting the restart preparation completion response. If the restart cancellation command is not received at the same time, the discarding of transmission / reception data is stopped. At this time, each ONU 2 may make a response for avoiding restart of the OLT 1.

  Each of the OLT 1 and each ONU 2 sets a value larger than ((round trip time between the OLT 1 and ONU 2) + (sixth set time ST6)) in the third set time ST3 and the eighth set time ST8. . For the fourth set time ST4, the fifth set time ST5 and the seventh set time ST7, a value larger than the round trip time between the OLT 1 and the ONU 2 is set. For the sixth set time ST6, a value larger than the transmission / reception interval of the data frames stored in the queue is set.

  With respect to the value of the sixth set time ST6 for monitoring the frame, in order to avoid restart of the OLT 1 during execution of the telephone application using SIP, a queue (ON) that temporarily stores data to be transmitted to the OLT 1 by the ONU 2 is queued ( A case of monitoring by the frame) monitoring unit 202 will be described.

  In the IETF standard RFC3550, it is recommended that the transmission interval of voice packets (RTP packets) be 20 milliseconds, and the sixth set time ST6 is set to at least 20 milliseconds. For example, if the sixth set time ST6 is set to 50 times the transmission interval, that is, 1 second or less, a plurality of frames can be monitored.

  Next, with respect to the value of the sixth set time ST6, in order to avoid restarting the OLT 1 during execution of the telephone application using SIP, the ONU 2 queues a queue for temporarily storing data received from the OLT 1 (frame The case where monitoring is performed by the monitoring unit 202 will be described.

Even if voice packets are transmitted accurately at an interval of 20 milliseconds, the reception side may be affected by packet loss or delay fluctuation and may not receive voice packets at equal intervals. ITU-T Y.M. When voice packets are transmitted and received with Class 0 communication quality defined in 1541, the packet loss rate is 10 ⁻³ or less and the packet delay fluctuation is 50 milliseconds or less. For example, even if delay fluctuation of a maximum of 50 milliseconds is taken into account, if the sixth set time ST6 is set to 70 milliseconds or more, at least one frame can be monitored. If the sixth set time ST6 is set to 50 times the transmission interval, that is, 1 second or less, 47 frames can be monitored at maximum. When the sixth set time ST6 is set to 1 second, the probability that no voice packet is observed during monitoring is (10 ⁻³ ) ⁴⁷ = 10 ⁻¹⁴¹ .

  Further, by setting the sixth set time ST6 to a value larger than the time-out time from when an INVITE message for establishing a SIP session is transmitted until 200 OK is received, the OLT 1 executing the telephone application is set. In addition to avoiding restart, restart of OLT 1 in the SIP session establishment phase can be avoided.

  Each ONU 2 may monitor the priority of data frames to be transmitted / received instead of monitoring the data stored in the queue in the ONU 2. In other words, the queue (frame) monitoring unit 202 monitors the priority of the data frame transmitted to the OLT 1, monitors the priority of the data frame received from the OLT 1, or both of them, thereby having a specific priority. You can understand the communication status of the application.

  For example, when it is determined that a data frame having a specific priority has not been transmitted or received during the sixth set time ST6 after the ONU 2 starts monitoring, the ONU 2 is restarted by the restart determination unit 211. The OAM signal processing unit 208 determines that the state is possible and transmits a restart preparation completion response to the OLT 1.

  Further, when a data frame having a specific priority is transmitted / received during the sixth set time ST6 after the ONU 2 starts monitoring, the ONU 2 determines that the restart determination unit 211 cannot restart. In order to prevent the OAM signal processing unit 208 from restarting the OLT 1, a restart preparation incomplete response is transmitted to the OLT 1.

  The priority of the data frame is identified by the CoS value stored in the VLAN tag header of the data frame or the ToS value stored in the IP header. Monitoring of data in the queue may be performed based on a specific priority.

  As described above, according to the communication control method of the second embodiment of the present invention, each ONU 2 that has received an instruction to prepare for restart from the OLT 1 monitors the queue in the ONU 2, and based on the monitoring result of the queue in the ONU 2. It is possible to control the restart time of the OLT 1.

  Next, a communication control method according to a third embodiment in the optical subscriber line terminating device (OLT) and the optical subscriber line terminating device (OLT) according to the present invention will be described with reference to the drawings.

(Example 3)
10 and 11 are sequence diagrams showing a communication control method according to the third embodiment of the present invention. In the communication control method according to the third embodiment shown in FIGS. 10 and 11, the queues in all ONUs 2 connected to the OLT 1 are monitored based on the report message received by the OLT 1 from the ONU 2, and the queues in the ONU 2 are monitored. The restart time of the OLT 1 is controlled based on the monitoring result and / or the monitoring result of the queue in the OLT 1. FIG. 10 shows an example when the OLT1 side queue is not monitored, and FIG. 11 shows an example when the OLT1 side queue is monitored. In FIG. 10 and FIG. 11, as an example, one optical subscriber line terminator (OLT) is represented by three optical network terminators (ONU-1, ONU-2 and ONU-3). Is described as being connected).

  Further, the optical subscriber line terminating device (OLT1) and the optical network terminating device (ONU-1, ONU-2, and ONU-3) according to the present invention can be realized by the configurations shown in FIGS. 5 and 6, respectively.

  First, as shown in FIG. 10, in step S31, the OLT 1 monitors the report messages received from all the ONUs 2 connected to the OLT 1 by the restart determination unit 111 via the message monitoring unit 106, and each ONU 2 Know the amount of data stored in the queue.

  The OLT 1 continues to monitor the report message received from the ONU 2 every period of the ninth set time ST9 by the restart determination unit 111 (steps S31 to S34), and all the ONUs 2 within the period of the ninth set time ST9. When the OLT 1 determines that there is no data or no longer exists in the queue, the OLT 1 determines that the data can be restarted, and the OAM signal processing unit 108 connects an initialization command for initializing the internal state of the ONU 2 to the OLT 1. The ONU 2 is not newly authenticated until the OLT 1 is restarted by the reset / blocking means 110 (step S35).

  Further, the OLT 1 uses the reset / blocking means 110 to transmit data to all the ONUs 2 and all the ONUs 2 so that no new session is established through the ONUs 2 during the tenth set time ST10 after the initialization command is transmitted. All data received from is discarded.

  In step S36, the ONU 2 that has received the initialization command transmits a reception confirmation response to the initialization command to the OLT 1 by the OAM signal processing unit 208, and initializes the internal state of the ONU 2 by the blocking / initialization unit 210. After the OLT 1 is restarted, it waits until a discovery process is executed.

  The OLT 1 that has received the reception confirmation response to the initialization command from all the ONUs 2 connected to the OLT 1 restarts the OLT 1 by the reset / blocking means 110 (step S37).

  Further, when the OLT 1 does not receive a reception confirmation response from the at least one ONU 2 within the tenth set time ST10 after the initialization command is transmitted, the OLT 1 uses the OAM signal processing means 108 to send the initialization command as a response. It is determined that it has not arrived at the ONU 2 that did not exist, and an initialization command is retransmitted to the ONU 2 that did not respond.

  When the OLT 1 determines that data exists in the queue of at least one ONU 2 during the ninth set time ST9 after the monitoring of the report message is started (step S32), the OLT 1 uses the restart determination unit 111. It is determined that the restart is impossible, and the restart of the OLT 1 is avoided (that is, the restart operation by the reset / blocking unit 110 is not executed).

  As shown in FIG. 11, the OLT 1 may monitor the data stored in the queue provided in the OLT 1 (or monitor the priority of the data frame) together with the monitoring of the report message (step S31-S34).

  As shown in FIG. 11, the OLT 1 continues monitoring by the restart determination unit 111 every period of the eleventh set time ST11 (steps S31 to S34), and all ONUs 2 within a certain period of the eleventh set time ST11. And when the queue (frame) monitoring means 112 determines that no data exists or no longer exists in the queue in the OLT 1 (or a specific priority) OLT 1 determines that the OLT 1 can be restarted, and the OAM signal processing means 108 initializes an initialization command for initializing the internal state of the ONU 2. As well as reset / blocking means 110 Newly so as not to authenticate the ONU2 until the restart of more OLT1.

  Further, the OLT 1 uses the reset / blocking means 110 to transmit data to all the ONUs 2 and all the ONUs 2 so that a new session is not established through the ONUs 2 during the twelfth set time ST12 after the initialization command is transmitted. Discard all data received from.

  The ONU 2 that has received the initialization command transmits a reception confirmation response to the initialization command generated by the OAM signal processing means 108 to the OLT 1, initializes the internal state of the ONU 2 by the reset / blocking means 110, and after restarting the OLT 1, The process waits until the discovery process is executed (step S38).

  The OLT 1 that has received the reception confirmation response to the initialization command from all the ONUs 2 connected to the OLT 1 restarts the OLT 1 by the reset / blocking means 110 (step S37).

  Further, when the reception confirmation response is not received from at least one ONU 2 within the twelfth set time ST12 after the OLT 1 transmits the initialization command, the OLT 1 has not arrived at the ONU 2 for which the initialization command did not respond. The OAM signal processing means 108 retransmits the initialization command to the ONU 2 that has not responded.

  When it is determined that data exists in the queue of at least one ONU 2 connected to the OLT 1 for a period of the eleventh set time ST11 after the OLT 1 starts monitoring the report message, or data is stored in the queue of the OLT 1 When the OLT 1 is determined to exist, the OLT 1 determines that the restart determination unit 111 is in a state in which the restart is impossible, and avoids the restart of the OLT 1.

  For the ninth set time ST9 and the eleventh set time ST11, a value larger than the transmission / reception interval of the data frame stored in the queue is set.

  With respect to the values of the ninth set time ST9 and the eleventh set time ST11, a queue in which the OLT 1 temporarily stores data received from the ONU 2 in order to avoid restart of the OLT 1 during execution of the telephone application using SIP. A case where the queue (frame) monitoring unit 112 monitors the above will be described.

  In the IETF standard RFC 3550, it is recommended that the transmission interval of voice packets (RTP packets) be 20 milliseconds, and the ninth set time ST9 and the eleventh set time ST11 are set to at least 20 milliseconds or more. For example, if the ninth set time ST9 and the eleventh set time ST11 are set to 50 times the transmission interval, that is, 1 second or less, a plurality of frames can be monitored.

  Next, regarding the values of the ninth set time ST9 and the eleventh set time ST11, in order to avoid restarting the OLT 1 during execution of the telephone application using SIP, the data that the OLT 1 transmits to the ONU 2 is temporarily stored. A case where the queue to be monitored is monitored by the queue (frame) monitoring unit 112 will be described.

Even if voice packets are transmitted accurately at an interval of 20 milliseconds, the reception side may be affected by packet loss or delay fluctuation and may not receive voice packets at equal intervals. ITU-T Y.M. When voice packets are transmitted and received with Class 0 communication quality defined in 1541, the packet loss rate is 10 ⁻³ or less and the packet delay fluctuation is 50 milliseconds or less. For example, even if delay fluctuation of a maximum of 50 milliseconds is taken into account, if the ninth set time ST9 and the eleventh set time ST11 are set to 70 milliseconds or more, at least one frame can be monitored. If the ninth set time ST9 and the eleventh set time ST11 are set to 50 times the transmission interval, that is, 1 second or less, 47 frames can be monitored at maximum. When the ninth set time ST9 and the eleventh set time ST11 are set to 1 second, the probability that no voice packet is observed during monitoring is (10 ⁻³ ) ⁴⁷ = 10 ⁻¹⁴¹ .

  Further, by setting the ninth set time ST9 and the eleventh set time ST11 to a value larger than the time-out time from when an INVITE message for establishing a SIP session is transmitted until 200 OK is received, In addition to avoiding restart of the OLT 1 during application execution, restart of the OLT 1 in the SIP session establishment phase can be avoided.

  In the tenth set time ST10 and the twelfth set time ST12, a value larger than the round trip time between the OLT 1 and the ONU 2 is set.

  The OLT 1 may monitor the priority of data frames transmitted and received instead of monitoring the data stored in the queue. In other words, the queue (frame) monitoring unit 112 monitors the priority of the data frame to be transmitted to the ONU 2, monitors the priority of the data frame received from the ONU 2, or both. You can understand the communication status of the application.

  For example, when it is determined that data does not exist or no longer exist in all the ONU2 queues during the eleventh set time ST11 after the OLT 1 starts monitoring, and data frames with a specific priority are transmitted and received. If not, the OLT 1 determines that the restart determination unit 111 is in a restartable state, and transmits an initialization command for initializing the internal state of the ONU 2 to all ONUs 2 connected to the OLT 1 by the OAM signal processing unit 108. At the same time, the ONU 2 is not newly authenticated until the OLT 1 is restarted by the reset / blocking means 110.

  Further, the OLT 1 uses the reset / blocking means 110 to transmit data to all the ONUs 2 and all the ONUs 2 so that a new session is not established through the ONUs 2 during the twelfth set time ST12 after the initialization command is transmitted. Discard all data received from.

  The ONU 2 that has received the initialization command transmits a reception confirmation response to the initialization command to the OLT 1 by the OAM signal processing unit 208, initializes the internal state of the ONU 2 by the blocking / initialization unit 210, and performs discovery ( Wait until the (Discovery) process is executed.

  The OLT 1 that has received the reception confirmation response to the initialization command from all the ONUs 2 connected to the OLT 1 restarts the OLT 1. In addition, when it is determined that at least one ONU 2 queue exists for a certain eleventh set time ST11 after the OLT 1 starts monitoring, or when a data frame having a specific priority is transmitted / received. If it is determined, the OLT 1 determines that the restart determination unit 111 determines that the restart is impossible, and avoids the restart of the OLT 1.

  The priority of the data frame is identified by the CoS value stored in the VLAN tag header of the data frame or the ToS value stored in the IP header. Monitoring of data in the queue may be performed based on a specific priority.

  Instead of providing a function for the OLT 1 to send an initialization command for initializing the internal state of the ONU 2 to each ONU, when each ONU 2 has not received a message from the OLT 1 for a certain period of time, the OLT 1 is restarted. A function may be provided that autonomously initializes the internal state and performs discovery processing.

  As described above, according to the communication control method of the third embodiment of the present invention, based on the report message received by the OLT 1 from the ONU 2, the queues in all the ONUs 2 connected to the OLT 1 are monitored, The restart time of the OLT 1 can be controlled based on the queue monitoring result and / or the queue monitoring result in the OLT 1.

  Next, a communication control method of Embodiment 4 in the optical subscriber line terminating device (OLT) and the optical subscriber line terminating device (OLT) according to the present invention will be described with reference to the drawings.

Example 4
12 to 15 are sequence diagrams showing a communication control method according to the fourth embodiment of the present invention. In the communication control method according to the fourth embodiment illustrated in FIGS. 12 to 15, the ONU 2 that has received an instruction to prepare for restart from the OLT 1 monitors the queue, and the OLT 1 receives from all the ONUs 2 connected to the OLT 1. The ONU 2 queue is monitored based on the report message, and the restart time of the OLT 1 is controlled based on the monitoring results. FIG. 12 shows an example of the case where the OLT1 queue is not monitored and the restart of the OLT1 is successful. FIG. 13 shows the case where the OLT1 queue is not monitored and the restart of the OLT1 fails. is there. FIG. 14 shows a case where the OLT 1 queue is monitored and the restart of the OLT 1 is successful. FIG. 15 shows a case where the OLT 1 queue is monitored and the restart of the OLT 1 fails. In FIG. 12 to FIG. 15, as an example, three optical network terminators (ONU-1, ONU-2, and ONU-3) are represented for one optical subscriber line terminator (OLT). Is described as being connected).

  Further, the optical subscriber line terminating device (OLT1) and the optical network terminating device (ONU-1, ONU-2, and ONU-3) according to the present invention can be realized by the configurations shown in FIGS. 5 and 6, respectively.

  First, as shown in FIGS. 12 to 15, in step S <b> 41, the OLT 1 uses the OAM signal processing unit 108 to send a restart preparation command to prepare for restart of the OLT 1 to all ONUs 2 connected to the OLT 1. Send.

  The ONU 2 that has received the restart preparation command starts monitoring the data stored in the queue included in the ONU 2 by the queue (frame) monitoring unit 206 and sends a restart preparation completion response to the OLT 1 by the OAM signal processing unit 208. (Step S42).

  As shown in FIG. 12, each ONU 2 continues to monitor the data in the queue in the ONU 2 by the queue (frame) monitoring means 206 during the 21st set time ST21, and no or no data exists in the queue in the ONU 2. When it is determined that there is no more (steps S42 to S44), each ONU 2 determines that the restart determination unit 211 determines that the restart is possible, and the MAC control unit 205 reports a report message for allowing the OLT 1 to restart to the OLT 1. Transmit (steps S43 to S44). Each ONU 2 transmits the ONU 2 to the OLT 1 by the blocking / initializing means 210 so that a new session is not established through the ONU 2 during the 22nd set time ST 22 until the ONU 2 responds to the initialization message from the OLT 1. All data to be received and data received from the OLT 1 are discarded.

  On the other hand, as shown in FIG. 13, each ONU 2 determines that data is present in the queue in the ONU 2 by the queue (frame) monitoring means 206 during the 21st set time ST21 after the monitoring of the queue in the ONU 2 is started. In the case (steps S42 to S44), the ONU 2 determines that the restart determination unit 211 cannot restart, and the MAC control unit 205 transmits a report message for avoiding restart of the OLT 1 to the OLT 1. (Steps S43 to S44).

  In the example of FIG. 13, ONU-1 shows a case where it is determined that data exists in the queue in ONU-1, and in this case, ONU-1 avoids restart of OLT1 (FIG. 13). Step S44 of ONU-1 shown in FIG.

  In step S42, the OLT 1 that has received the restart preparation completion response from all the ONUs 2 connected to the OLT 1 monitors the report messages received from all the ONUs 2, and determines the amount of data stored in the queue of each ONU 2. To grasp.

  Further, the OLT 1 determines that data does not exist or no longer exists in the queue in the OLT 1 by the queue (frame) monitoring unit 112 during the 14th set time ST14 after receiving the restart preparation completion response from all the ONUs 2. In such a case, the OLT 1 determines that the restart can be restarted by the restart determination unit 111, and the OLT 1 uses the OAM signal processing unit 108 to initialize all the ONT2 initialization commands that are used to initialize the internal state of the ONU 2. The ONU 2 is not newly authenticated until the OLT 1 is restarted by the reset / blocking unit 110 (step S45).

  Each ONU 2 that has received the initialization command transmits a reception confirmation response to the initialization command to the OLT 1 by the OAM signal processing means 208 (step S46), initializes the internal state of the ONU 2, and performs discovery after the OLT 1 is restarted (Discovery) Wait until processing is executed.

  The OLT 1 that has received the reception confirmation response to the initialization command from all the ONUs 2 connected to the OLT 1 restarts the OLT 1 (step S47).

  If the OLT 1 does not receive a restart preparation completion response from at least one ONU 2 within the thirteenth set time ST13 after the restart preparation command is transmitted, the OLT 1 has not received the restart preparation command at the ONU 2 And a restart preparation command is retransmitted to the ONU 2.

  Further, when the reception confirmation response is not received from at least one ONU 2 within the fifteenth set time ST15 after the transmission of the initialization command by the OLT 1, the OLT 1 has not arrived at the ONU 2 for which the initialization command has not responded. The initialization command is retransmitted to the ONU 2 that has not responded.

  On the other hand, as shown in FIG. 13, at least one ONU 2 determines that data exists in the queue in the ONU 2 during the 21st set time ST21, and sends a report message to the OLT 1 to avoid restart of the OLT 1 In such a case, the OLT 1 determines that the restart determination unit 111 cannot restart. Then, the OLT 1 transmits a restart cancellation command for canceling the ONU 2 restart preparation by the OAM signal processing means 108 to all the ONUs 2 connected to the OLT 1, and avoids the restart of the OLT 1 (step S49).

  Each ONU 2 that has received the restart cancellation command transmits a restart cancellation completion response to the OLT 1 by the OAM signal processing means 208, and stops the discard of transmission / reception data (step S50).

  If the OLT 1 does not receive a restart cancellation completion response from at least one ONU 2 within the sixteenth set time ST16 after transmitting the restart cancellation command, the OLT 1 performs the restart by the OAM signal processing means 108. It is determined that the activation cancel command has not arrived at the ONU 2 that has not responded, and the restart cancel command is retransmitted to the ONU 2 that has not responded.

  In this embodiment, each ONU 2 starts discarding the transmission / reception data in the queue in the ONU 2 during the 22nd set time ST22 after monitoring the transmission / reception data in the ONU 2 queue. Therefore, the ONU 2 does not receive the initialization command or the restart cancellation command within the 22nd set time ST22 after starting to discard all the data transmitted to the OLT 1 and the data received from the OLT 1, or the restart preparation is completed. If the initialization command or the restart cancellation command is not received within the 23rd set time ST23 after transmitting the response, the discarding of the transmission / reception data is stopped. At this time, the ONU 2 may transmit a response for avoiding restart of the OLT 1 to the OLT 1.

  As shown in FIGS. 14 and 15, the OLT 1 may monitor the data stored in the queue provided in the OLT 1 (that is, monitor the data frame) together with the monitoring of the report message.

  As shown in FIG. 14, the OLT 1 that has received the restart preparation completion response from all the ONUs 2 connected to the OLT 1 monitors the report messages received from all the ONUs 2 and the queues in the OLT 1 and stores them in the ONU 2 queues. To know the amount of data being used.

  In FIG. 14, the OLT 1 has no data in the queues in all the ONUs 2 connected to the OLT 1 based on the report message during the 18th set time ST18 after receiving the restart preparation responses from all the ONUs 2. Alternatively, when it is determined that the data does not exist and when it is determined that the data does not exist or no longer exists in the queue of the OLT 1, the OLT 1 determines that the restart can be restarted by the restart determination unit 111, and the OAM signal processing unit The initialization command for initializing the internal state of the ONU 2 is transmitted to all ONUs 2 connected to the OLT 1 by 108, and the ONU 2 is not newly authenticated until the OLT 1 is restarted by the reset / blocking means 110. .

  In step S45, each ONU 2 that has received the initialization command transmits an acknowledgment response to the initialization command to the OLT 1 by the OAM signal processing means 208, initializes the internal state of the ONU 2 by the blocking / initialization means 210, and After the restart, the system waits until a discovery process is executed.

  The OLT 1 that has received the reception confirmation response to the initialization command from all the ONUs 2 connected to the OLT 1 restarts the OLT 1 by the reset / blocking means 110 (step S47).

  If the OLT 1 does not receive a restart preparation completion response from at least one ONU 2 within the 17th set time ST17 after the transmission of the restart preparation command, the OLT 1 sends the restart preparation command to the OAM signal processing means 108. It is determined that it has not arrived at the ONU 2 and a restart preparation command is retransmitted to the ONU 2.

  In addition, if the reception confirmation response is not received from at least one ONU 2 within the 19th set time ST19 after the OLT 1 transmits the initialization command, the OLT 1 has not arrived at the ONU 2 for which the initialization command did not respond. The initialization command is retransmitted to the ONU 2 that has not responded.

  On the other hand, as shown in FIG. 15, the OLT 1 receives a report message indicating that data exists in the queue of at least one ONU 2 connected to the OLT 1 during the 18th set time ST 18, or the queue of the OLT 1 When the OLT 1 determines that there is data, the OLT 1 determines that the restart is not possible by the restart determination unit 111 and connects the restart cancellation command for canceling the ONU 2 restart preparation to the OLT 1 by the OAM signal processing unit 108. It is transmitted to all the ONUs 2, and the restart of the OLT 1 is avoided (step S49).

  The ONU 2 that has received the restart cancel command transmits a restart cancel completion response to the OLT 1 by the OAM signal processing means 208 and stops discarding transmission / reception data (step S50).

  If the OLT 1 does not receive a restart cancellation completion response from at least one ONU 2 within the 19th set time ST19 after transmitting the restart cancellation command, the OLT 1 is restarted by the OAM signal processing means 108. It is determined that the cancel command has not arrived at the ONU 2 that did not respond, and the restart cancel command is retransmitted to the ONU 2 that did not respond.

  The 13th set time ST13, the 15th set time ST15, the 16th set time ST16, the 17th set time ST17, the 19th set time ST19, the 20th set time ST20 and the 22nd set time ST22 include OLT1 and ONU2. Set a value larger than the round trip time.

  In the fourteenth set time ST14, the eighteenth set time ST18, and the twenty-first set time ST21, a value larger than the transmission / reception control of the data frame stored in the queue is set.

  Regarding the values of the 14th set time ST14, the 18th set time ST18 and the 21st set time ST21 to be monitored, the ONU 2 transmits to the OLT 1 in order to avoid restarting the OLT 1 during execution of the telephone application using SIP. A case in which a queue for temporarily storing data to be stored and / or a queue for temporarily storing data received by the OLT 1 from the ONU 2 will be described.

  In IETF standard RFC3550, it is recommended that the transmission interval of voice packets (RTP packets) be 20 milliseconds, and the 14th set time ST14, the 18th set time ST18, and the 21st set time ST21 are at least 20 milliseconds or more. Set to. For example, if the 14th set time ST14, the 18th set time ST18, and the 21st set time ST21 are set to 50 times the transmission interval, that is, 1 second or less, a plurality of frames can be monitored.

  Next, regarding the values of the 14th set time ST14, the 18th set time ST18 and the 21st set time ST21, the data received by the ONU 2 from the OLT 1 in order to avoid the restart of the OLT 1 during execution of the telephone application using SIP. A case where a queue for temporarily storing data and / or a queue for temporarily storing data transmitted from the OLT 1 to the ONU 2 will be described.

Even if voice packets are transmitted accurately at an interval of 20 milliseconds, the reception side may be affected by packet loss or delay fluctuation and may not receive voice packets at equal intervals. ITU-T Y.M. When voice packets are transmitted and received with Class 0 communication quality defined in 1541, the packet loss rate is 10 ⁻³ or less and the packet delay fluctuation is 50 milliseconds or less. For example, even if delay fluctuation of a maximum of 50 milliseconds is taken into account, if the 14th set time ST14, the 18th set time ST18, and the 21st set time ST21 are set to 70 milliseconds or more, at least one frame is monitored. be able to. If the 14th set time ST14, the 18th set time ST18 and the 21st set time ST21 are set to 50 times the transmission interval, that is, 1 second or less, 47 frames can be monitored at maximum. When the 14th set time ST14, the 18th set time ST18, and the 21st set time ST21 are set to 1 second, the probability that no voice packet is observed during monitoring is (10 ⁻³ ) ⁴⁷ = 10 ⁻¹⁴¹ .

  Further, the 14th set time ST14, the 18th set time ST18, and the 21st set time ST21 are larger than the time-out time until the 200 OK is received after the INVITE message for establishing the SIP session is transmitted. By doing so, in addition to avoiding restart of the OLT 1 during execution of the telephone application, restart of the OLT 1 in the SIP session establishment phase can be avoided.

  In the 23rd set time ST23, ((round trip time between OLT and ONU) + (18th set time ST18)) or ((round trip time between OLT and ONU)) + (21st set time ST21) Set a larger value than)).

  Instead of monitoring the data stored in the queue, the OLT 1 or the ONU 2 may monitor the priority of the transmitted / received data frame. In other words, by monitoring the priority of the data frame transmitted to the OLT 1 or ONU 2, monitoring the priority of the data frame received from the OLT 1 or ONU 2, or both, the communication state of the application having a specific priority Can be grasped.

  For example, when it is determined that data does not exist or no longer exist in the queues of all ONUs 2 during the period of the 14th set time ST14, the 18th set time ST18 or the 21st set time ST21 after the OLT 1 or ONU 2 starts monitoring When it is determined that a data frame having a specific priority is not transmitted / received or is no longer transmitted / received, the OLT 1 determines that the restart determination unit 111 determines that the data frame can be restarted, and the OAM signal processing unit 108 determines that the ONU 2 An initialization command for initializing the internal state is transmitted to all the ONUs 2 connected to the OLT 1, and the ONU 2 is not newly authenticated until the OLT 1 is restarted by the reset / blocking unit 110.

  In addition, the OLT 1 transmits to the ONUs 2 by the reset / blocking means 110 so that no new session is established through the ONU 2 during the 15th set time ST15 or the 19th set time ST19 after the initialization command is transmitted. All data received and data received from all ONUs 2 are discarded.

  The ONU 2 that has received the initialization command transmits a reception confirmation response to the initialization command to the OLT 1, initializes the internal state of the ONU 2, and waits for discovery (Discovery) processing to be executed after the OLT 1 is restarted.

  The OLT 1 that has received the reception confirmation response to the initialization command from all the ONUs 2 connected to the OLT 1 restarts the OLT 1. Also, when there is a queue of at least one ONU 2 during the period of the 14th set time ST14, the 18th set time ST18 or the 21st set time ST21 after the OLT 1 starts monitoring, or data of a specific priority When the frame is transmitted / received, the OLT 1 determines that the restart is impossible, and avoids the restart of the OLT 1.

  The priority of the data frame is identified by the CoS value stored in the VLAN tag header of the data frame or the ToS value stored in the IP header. Monitoring of data in the queue may be performed based on a specific priority.

  As described above, according to the communication control method of the fourth embodiment of the present invention, the ONU 2 that has received an instruction to prepare for restart from the OLT 1 monitors the queue, and the OLT 1 is connected to all the ONUs 2 connected to the OLT 1. It is possible to monitor the queue of the ONU 2 based on the received report message, and to control the restart time of the OLT 1 based on these monitoring results.

  Next, a common modification in the communication control method of the first to fourth embodiments in the optical subscriber line terminating device (OLT) and the optical subscriber line terminating device (OLT) according to the present invention will be described as another embodiment.

(Other examples)
For example, there is a case where data is stored by being sorted into a high priority queue and a low priority queue by an application. A specific priority queue monitored by an embodiment of the present invention refers to a high priority queue that stores real-time application data such as voice data. The ONU 2 and the OLT 1 monitor only the high priority queue and determine that data does not exist or no longer exist in the OLT 1 high priority queue, or data is stored in the high priority queues of all ONUs 2 connected to the OLT 1. If the OLT 1 is restarted when it is determined that it does not exist or does not exist, restart during execution of the real-time application can be avoided.

  On the other hand, if the application stored in the low priority queue does not have real-time characteristics, even if the OLT 1 is restarted during execution, the influence on the communication terminal used by the user compared to the real-time application There are few. Therefore, it is possible to remove the low priority queue monitoring function.

  However, instead of monitoring a queue with a specific priority, it is also possible to monitor all queues with a priority.

  Further, the queue monitoring of the ONU 2 and the OLT 1 may be performed on a queue that stores data to be transmitted to the OLT 1 or the ONU 2, or may be performed on a queue that stores data received from the OLT 1 or the ONU 2. Or you may carry out with respect to the queue of both transmission and reception.

  For example, in order to avoid restart when an interactive application such as a telephone is being executed, it is necessary to monitor both transmission and reception queues.

  On the other hand, in order to avoid restart when a one-way application such as video distribution is being executed, it is necessary to monitor one of the transmission / reception queues.

  Restart preparation completion response, restart preparation incomplete response, restart cancellation completion response, restart preparation command due to missing reception confirmation response to initialization command between OLT 1 and ONU 2, restart cancellation command, In order to prevent re-transmission for each of the initialization command and the initialization command, the ONU 2 sends each of the restart preparation completion response, the restart preparation incomplete response, the restart cancellation completion response, and the reception confirmation response to the initialization command to OLT1. A plurality of messages may be transmitted.

  The time until the OLT 1 is restarted after avoiding the restart of the OLT 1 may be set as the 24th set time ST24, and the waiting means may be further provided in the OLT 1 or the ONU 2. For example, when a time period for restarting the OLT 1 is determined in advance and the OLT 1 cannot be restarted during that time period, the operation is performed so that the OLT 1 is restarted by waiting until the next time period. Can be considered.

  In the OLT 1, instead of discarding the data transmitted to the ONU 2 and the data received from the ONU 2, the amount of data permitted to be transmitted in the GATE message (that is, the transmission permission message) in MPCP may be set to zero.

  In addition, instead of discarding the data transmitted to the OLT 1 and the data received from the OLT 1 in the ONU 2, the amount of data that requests transmission permission in the REPORT message (that is, the report message) in MPCP may be zero.

  The communication states in the OLT 1 and / or the ONU 2 can be monitored by combining the above-described embodiments. Moreover, it can change from each above-mentioned Example and can adapt it according to a use.

  In the above-described embodiments, the case of E-PON has been described. However, the present invention is also applied to other PONs, for example, B-PON and G-PON conforming to the ITU-T recommendation, and also WDM-PON and CDM-PON. Obviously we can do it. Further, it can be clearly applied to the point-to-point access system shown in FIG. Therefore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  According to the present invention, it is possible to appropriately monitor the communication state in the OLT and / or the ONU and control the restart of the OLT, which is useful for an optical communication system of a network that transmits and receives transmission data.

It is a figure which shows the structure of an optical network. It is a figure which shows the structure of a passive optical network (PON). It is a functional block diagram of the conventional optical subscriber line termination | terminus apparatus (OLT). It is a functional block diagram of the conventional optical network termination unit (ONU). 1 is a functional block diagram of an optical subscriber line termination device (OLT) according to the present invention. FIG. It is a functional block diagram of the optical network termination unit (ONU) by this invention. It is a sequence diagram showing the communication control method of Example 1 by this invention. It is a sequence diagram showing the time of a successful restart of the communication control method of Example 2 by this invention. It is a sequence diagram showing the time of restart failure of the communication control method of Example 2 by this invention. It is a sequence diagram showing the time of not performing OLT side queue monitoring (frame monitoring) in the communication control method according to the third embodiment of the present invention. It is a sequence diagram showing the time of performing queue monitoring (frame monitoring) on the OLT side in the communication control method according to the third embodiment of the present invention. It is a sequence diagram showing the case where the OLT-side queue monitoring (frame monitoring) is not performed in the communication control method according to the fourth embodiment of the present invention and the OLT is successfully restarted. It is a sequence diagram showing the case where the OLT side queue monitoring (frame monitoring) is not performed and the restart of the OLT fails in the communication control method according to the fourth embodiment of the present invention. It is a sequence diagram showing the case where the OLT side queue monitoring (frame monitoring) is performed in the communication control method according to the fourth embodiment of the present invention and the OLT is successfully restarted. It is a sequence diagram showing the case where the OLT side queue monitoring (frame monitoring) in the communication control method according to the fourth embodiment of the present invention is performed, and the case where the OLT restart fails.

Explanation of symbols

1 OLT
2,2-1,2-2,2-n ONU
3,3-1,3-2,3-n communication terminal 4 splitter 11 conventional OLT
22 Conventional ONU
101 PON signal processing means 102 bridging means 103 SNI port 104 PON-IF port 105 MAC control control 106 message monitoring means 107 DBA means 108 OAM signal processing means 109 reset means 110 reset / blocking means 111 restart judgment means 112 queue (frame) Monitoring means 201 PON signal processing means 202 Bridge circuit 203 UNI port 204 PON-IF port 205 MAC control control 206 Queue (frame) monitoring means 208 OAM signal processing means 210 Blocking / initializing means 211 Restart determination means

Claims (25)

Means for monitoring the presence and / or amount of data in a queue for temporarily storing data to be transmitted and received;
When there is data in the queue, it is determined that an optical subscriber line terminating device (OLT) is communicating, and when there is no data or no longer exists in the queue, the OLT is not communicating. Means to judge,
An optical network termination device comprising: Means for monitoring whether there is a transmission / reception of a data frame of a specific priority;
When there is a transmission / reception of a data frame with a specific priority, it is determined that the optical subscriber line termination device (OLT) is communicating, and transmission / reception of a data frame with a specific priority does not exist or no longer exists. A means for determining that the OLT is not communicating;
An optical network termination device comprising: In the optical network termination unit (ONU) according to claim 1,
The optical network termination device, wherein the queue is a high priority queue among a plurality of queues having different priorities. In the optical network termination unit (ONU) according to any one of claims 1 to 3,
The apparatus further comprises means for avoiding restart of the OLT when it is determined that the OLT is communicating, and for restarting the OLT when it is determined that the OLT is not communicating. Optical network terminator. Means for monitoring the presence and / or amount of data in a queue for temporarily storing data to be transmitted and received;
Means for determining that communication is in progress when data is in the queue, and determining that communication is not in progress when data is not present or no longer exists in the queue;
An optical subscriber line termination device comprising: Means for monitoring whether there is a transmission / reception of a data frame of a specific priority;
If there is a transmission / reception of a data frame with a specific priority, it is determined that the communication is in progress. If transmission / reception of a data frame with a specific priority does not exist or no longer exists, it is determined that the communication is not in progress. Means,
An optical subscriber line termination device comprising: Means for monitoring the presence and / or amount of data stored in the queue of all optical network termination units (ONUs) connected to the optical subscriber line termination unit (OLT);
Means for determining that communication is in progress when data is present in at least one ONU queue, and determining that communication is not being performed when data is not present or no longer exists in all of the ONU queues When,
An optical subscriber line termination device comprising: In the optical subscriber line terminating device (OLT) according to claim 5 or 7,
The optical subscriber line terminating apparatus, wherein the queue is a high priority queue among a plurality of queues having different priorities. In the optical subscriber line termination device (OLT) according to any one of claims 5 to 8,
An optical subscriber line terminating apparatus further comprising means for avoiding restart when it is determined that communication is in progress and performing restart when it is determined that communication is not being performed. In an optical network system that performs point-to-point or point-to-multipoint communication, when an optical subscriber line termination unit (OLT) once disconnects from the optical network termination unit (ONU) and restarts, the OLT Or a method of controlling the restart time of the OLT according to the communication state of the ONU connected to the OLT,
Each of the ONUs includes a first queue that temporarily stores data to be transmitted to the OLT for each priority, a second queue that temporarily stores data received from the OLT for each priority, and the first queue First monitoring means for monitoring the presence and / or amount of data in the queue and the second queue;
When each of the ONUs receives a reboot preparation command from the OLT,
Each processing procedure of the ONU is as follows:
Determining whether data of a specific priority is stored in the first queue and the second queue for a predetermined set time period by the first monitoring means;
A step of recognizing that the OLT cannot be restarted when the first monitoring means determines that at least one of the first queue and the second queue has data of a specific priority; and / or Responding to the OLT that restart preparation is not complete;
A step of recognizing that the OLT can be restarted when it is determined by the first monitoring means that data of a specific priority does not exist or no longer exists in both the first queue and the second queue; And / or responding to the OLT to be ready for rebooting, and
The OLT avoids restarting the OLT until receiving a response indicating that the restart preparation is complete from all of the ONUs,
Each of the ONUs controls a response indicating that the restart preparation is completed to the OLT to avoid restart of the OLT. In an optical network system that performs point-to-point or point-to-multipoint communication, when an optical subscriber line termination unit (OLT) once disconnects from the optical network termination unit (ONU) and restarts, the OLT Or a method of controlling the restart time of the OLT according to the communication state of the ONU connected to the OLT,
Each of the ONUs includes first monitoring means for monitoring whether or not there is transmission / reception of a data frame having a specific priority,
When each of the ONUs receives a reboot preparation command from the OLT,
Each processing procedure of the ONU is as follows:
Determining whether or not there is a transmission / reception of a data frame of a specific priority by the first monitoring means for a predetermined set time period;
When the first monitoring means determines that a data frame with a specific priority is transmitted / received, the OLT recognizes that the OLT cannot be restarted and / or indicates that the restart preparation is not completed. A step of responding to
A step of recognizing that the OLT is in a restartable state and / or completion of restart preparation when it is determined by the first monitoring means that transmission / reception of a data frame of a specific priority does not exist or no longer exists Responding to the OLT,
The OLT avoids restarting the OLT until receiving a response indicating that the restart preparation is complete from all of the ONUs,
Each of the ONUs controls a response indicating that the restart preparation is completed to the OLT to avoid restart of the OLT. In an optical network system that performs point-to-point or point-to-multipoint communication, when an optical subscriber line termination unit (OLT) once disconnects from the optical network termination unit (ONU) and restarts, the OLT Or a method of controlling the restart time of the OLT according to the communication state of the ONU connected to the OLT,
The OLT has a third queue for temporarily storing data to be transmitted to each of the ONUs for each priority, a fourth queue for temporarily storing data received from each of the ONUs for each priority, and Second monitoring means for monitoring the presence and / or amount of data in the third queue and the fourth queue;
The processing procedure of the OLT is as follows:
Determining whether or not data of a specific priority is stored in the third queue and the fourth queue for a predetermined set time period by the second monitoring means;
A step of restarting the OLT when the second monitoring means determines that data of a specific priority does not exist or no longer exists in both the third queue and the fourth queue;
The communication control method characterized by including. In an optical network system that performs point-to-point or point-to-multipoint communication, when an optical subscriber line termination unit (OLT) once disconnects from the optical network termination unit (ONU) and restarts, the OLT Or a method of controlling the restart time of the OLT according to the communication state of the ONU connected to the OLT,
The OLT has second monitoring means for monitoring whether or not there is a transmission / reception of a data frame having a specific priority,
The processing procedure of the OLT is as follows:
Determining by the second monitoring means whether or not there is transmission / reception of a data frame of a specific priority for a predetermined set time period;
Performing a restart of the OLT when it is determined by the second monitoring means that transmission / reception of a data frame of a specific priority does not exist or no longer exists;
The communication control method characterized by including. In the communication control method according to any one of claims 10 to 13,
The ONU monitors a queue for temporarily storing data to be transmitted to the OLT and / or a queue for temporarily storing data received from the OLT, and reports the amount of data stored in the queue. A communication control method comprising reporting to the OLT by a message. The communication control method according to claim 10, 12 or 14,
The communication control method, wherein the queue is a high priority queue among a plurality of queues having different priorities. In an optical subscriber line terminating device (OLT) that is restarted by the communication control method according to claim 12, 13 or 15,
A function of transmitting a restart preparation command to all ONUs connected to the OLT when the connection with all ONUs connected to the OLT is once cut and restarted;
A function of receiving a response indicating completion of restart preparation or incomplete preparation of restart from all ONUs connected to the OLT;
An optical subscriber line terminating apparatus, wherein when a response to completion of restart preparation is received from all ONUs connected to the OLT, the OLT is restarted. In an optical subscriber line terminating device (OLT) that is restarted by the communication control method according to claim 10,
When all the ONUs connected to the OLT are disconnected once and restarted,
A function for transmitting an initialization command for initializing the internal state of the ONU to all the ONUs connected to the OLT, and for preventing the ONU from being newly authenticated before restarting;
A function of restarting the OLT when reception confirmation responses to the initialization command are received from all ONUs within a predetermined set time after transmitting the initialization command;
A function of transmitting an initialization command again to an ONU that has not responded when a reception confirmation response to the initialization command is not received from at least one ONU within a predetermined set time after the initialization command is transmitted; ,
An optical subscriber line termination device comprising: In the optical network termination unit (ONU) connected to the OLT that is restarted by the communication control method according to claim 10,
Upon receipt of an initialization command received from the OLT for initializing the internal state of the ONU, a reception confirmation response to the initialization command is transmitted to the OLT and the internal state of the ONU is initialized. Function and
An optical network termination device comprising: In an optical subscriber line terminating device (OLT) that is restarted by the communication control method according to claim 10, 11 or 15,
A restart preparation command for preparing for the restart of the OLT is transmitted to all ONUs connected to the OLT, and the restart is performed from at least one ONU within a predetermined set time after the restart preparation command is transmitted. A function of transmitting a restart preparation command to an ONU that has not responded again when a preparation completion response or a restart preparation incomplete response has not been received;
When a restart preparation completion response is received from all ONUs within the predetermined set time, an initialization command for initializing the internal state of the ONU is transmitted to all ONUs and until the restart is performed. A new function not to authenticate the ONU;
If a restart preparation incomplete response is received from at least one ONU within the predetermined set time, a restart cancel command for canceling the restart preparation is transmitted to all ONUs to avoid restarting the OLT. Function to
A function of restarting the OLT when reception confirmation responses to the initialization command are received from all ONUs within a predetermined set time after transmitting the initialization command;
A function of transmitting an initialization command again to an ONU that has not responded when a reception confirmation response to the initialization command is not received from at least one ONU within a predetermined set time after the initialization command is transmitted; ,
If a restart cancel completion response is not received from at least one ONU within a predetermined set time after transmitting the restart cancel command, the restart cancel command is transmitted again to the ONU that has not responded. Function and
An optical subscriber line termination device comprising: In an optical network termination unit (ONU) connected to an OLT that is restarted by the communication control method according to claim 10, 11 or 15,
Monitoring the presence / absence of data stored in the first queue and the second queue or the priority of the data frame by receiving a restart preparation command for preparing the OLT to be restarted by the first monitoring unit When it is determined that there is data in the queue or a data frame of a specific priority is transmitted / received within a predetermined set time period after the monitoring is started, A function of transmitting a startup preparation incomplete response to the OLT to avoid restart of the OLT;
When it is determined that data does not exist or no longer exists in the first queue and the second queue within the predetermined set time period, or a data frame having a specific priority is not transmitted / received or is not transmitted / received A function to send a reboot preparation completion response to the OLT,
A function of discarding all data to be transmitted to the OLT and data received from the OLT within a predetermined set time period after transmitting the restart preparation completion response;
When an initialization command for initializing the ONU internal state is received from the OLT that has received the restart preparation completion response from all ONUs, a reception confirmation response to the initialization command is transmitted to the OLT. A function for initializing the internal state of the ONU;
When a restart cancellation command for canceling the restart preparation is received from the OLT within the predetermined set time period after transmitting the restart preparation completion response, a restart cancellation completion response is transmitted to the OLT. , The function to stop discarding of sent and received data,
When the initialization command or the restart cancellation command is not received within the predetermined set time after receiving the restart preparation command, or the initial setting within the predetermined set time after transmitting the restart preparation completion response. A function to stop discarding the data in the first queue and the second queue when the activation command or the restart cancellation command is not received;
An optical network termination device comprising: In an optical subscriber line terminating device (OLT) that is restarted by the communication control method according to claim 14 or 15,
When a report message indicating that there is data in the queue of at least one ONU for a predetermined set time period after monitoring of the report messages received from all ONUs connected to the OLT is started, A function of avoiding restart of the OLT;
A function for restarting the OLT when receiving a report message indicating that no data exists or no longer exists in the queues of all ONUs during the predetermined set time;
An optical subscriber line termination device comprising: In an optical subscriber line terminating device (OLT) that is restarted by the communication control method according to claim 14 or 15,
At least one period of a predetermined set time from the start of monitoring of report messages received from all ONUs connected to the OLT and monitoring of the priority of data or data frames stored in the queue of the OLT When a report message indicating that there is data in one ONU queue is received, or when it is determined that there is data in the OLT queue, or when it is determined that a data frame of a specific priority is transmitted / received, A function of avoiding restart of the OLT;
When a report message indicating that no data exists or no longer exists in all ONU queues during the predetermined set time period and when it is determined that no data exists or no longer exists in the OLT queue Or a function to restart the OLT when it is determined that a data frame having a specific priority is not transmitted or received, or is no longer transmitted or received;
An optical subscriber line termination device comprising: In an optical subscriber line terminating device (OLT) that is restarted by the communication control method according to claim 14 or 15,
A function of transmitting a restart preparation command for preparing for the restart of the OLT to all ONUs connected to the OLT;
A function of transmitting a restart preparation command again to an ONU that has not responded when a restart preparation completion response is not received from at least one ONU within a predetermined set time after the restart preparation command is transmitted When,
A function for starting monitoring of report messages received from all ONUs connected to the OLT when a response to completion of restart preparation is received from all ONUs within the predetermined set time;
When a report message indicating that no data exists or no longer exists in the queues of all ONUs for a predetermined set time period after the start of monitoring is used to initialize the internal state of the ONUs A function to send an initialization command to all ONUs and not to newly authenticate an ONU until a restart is performed;
A function for restarting the OLT when reception confirmation responses to the initialization command are received from all ONUs within a predetermined set time after transmitting the initialization command;
A function of transmitting an initialization command to an ONU that has not responded again when a reception confirmation response to the initialization command is not received from at least one ONU within the predetermined set time;
Restart for canceling the restart preparation when a report message indicating that there is data in the queue of at least one ONU is received during the predetermined set time period in which monitoring of report messages received from all ONUs is started. A function of sending a cancel command to all ONUs to avoid restart of the OLT;
A function of transmitting a restart cancellation command to an ONU which has not responded again when a restart cancellation completion response is not received from at least one ONU within a predetermined set time after transmitting the restart cancellation command. When,
An optical subscriber line termination device comprising: In an optical subscriber line terminating device (OLT) that is restarted by the communication control method according to claim 14 or 15,
A function of transmitting a restart preparation command for preparing for restart of the OLT to all ONUs connected to the OLT;
A function of transmitting a restart preparation command again to an ONU that has not responded when a restart preparation completion response is not received from at least one ONU within a predetermined set time after the restart preparation command is transmitted When,
If a response to completion of restart preparation is received from all ONUs within the predetermined set time, monitoring of report messages received from all ONUs connected to the OLT and storing them in the queue of the OLT A function to start monitoring data or data frame priority;
When a report message indicating that data does not exist or no longer exists in all ONU queues for a predetermined set time period after the start of the monitoring, and a data frame having a specific priority in the OLT When the transmission / reception is not performed or is not performed, the initialization command for initializing the internal state of the ONU is transmitted to all ONUs, and new ONU authentication is not performed until restarting. Function to
When a report message indicating that data exists in the queue of at least one ONU is received during the predetermined set time period, or when it is determined that a data frame having a specific priority is transmitted / received in the OLT A function of sending a restart cancel command for canceling restart preparation to all ONUs to avoid restart of the OLT;
A function for restarting the OLT when reception confirmation responses to the initialization command are received from all ONUs within a predetermined set time after transmitting the initialization command;
A function of transmitting an initialization command to an ONU that has not responded again when a reception confirmation response to the initialization command is not received from at least one ONU within the predetermined set time;
A function of transmitting a restart cancellation command to an ONU which has not responded again when a restart cancellation completion response is not received from at least one ONU within a predetermined set time after transmitting the restart cancellation command. When,
An optical subscriber line termination device comprising: In an optical network termination unit (ONU) connected to an OLT that is restarted by the communication control method according to claim 14 or 15,
A function of transmitting a restart preparation completion response to the OLT in response to reception of a restart preparation command for preparing for the restart of the OLT;
After transmission of the restart preparation completion response, monitoring of the presence / absence or amount of data stored in the queue of the ONU, or monitoring of the priority of the data frame is started, and a predetermined set time after starting the monitoring If it is determined that there is data in the ONU queue during this period, or if it is determined that a data frame of a specific priority has been transmitted / received, a report message to that effect is transmitted to the OLT and the OLT The ability to avoid restarts,
In the monitoring, when it is determined that data does not exist or no longer exists in the queue of the ONU, or when it is determined that a data frame of a specific priority is not transmitted / received or is no longer transmitted / received, A function of discarding all data to be transmitted to the OLT and data received from the OLT in the ONU queue during a predetermined set time period;
Upon receipt of an initialization command received from the OLT for initializing the internal state of the ONU, a reception confirmation response to the initialization command is transmitted to the OLT and the internal state of the ONU is initialized. Function and
If a restart cancel command for canceling the restart preparation is received from the OLT within a predetermined set time period after the monitoring, a restart cancel completion response is transmitted to the OLT and the transmission / reception data is discarded. With the ability to stop
When the initialization command or the restart cancellation command is not received within the predetermined set time after receiving the restart preparation command, or within the predetermined set time after monitoring the ONU queue Or an optical network terminating device comprising a function of stopping discarding of data in the first queue and the second queue when a restart cancellation command is not received.

Images