Method and equipment for switching balanced time delay in passive optical network
By setting the balanced delay information table of the primary and backup PON ports in the passive optical network and calculating and synchronizing the balanced delay of the ONU, the problem of upstream time slot misalignment during ONU switching is solved, and adaptive delay balance and low-latency switching are achieved.
Patent Information
- Application Number
- CN202510899416.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-30
- Publication Date
- 2025-09-12
AI Technical Summary
In a passive optical network, when an ONU switches to a backup PON port, upstream timeslot misalignment may occur, causing data to arrive at the OLT earlier or later. Existing technologies have failed to effectively address this problem.
By setting the equalization delay information table of the active and standby PON ports, calculating and recording the equalization delay of the ONU, synchronizing and modifying the equalization delay information, delay balance is ensured during the switching process. The OLT manages the EQD difference and the ONU does not need to re-measure the distance.
The adaptive balancing of ONU delay during the switching process is achieved, which reduces the switching delay and improves the redundancy protection capability of the network.
Smart Images
Figure CN120640164A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to communication technology, and more particularly to a method and device for switching equalized delay in a passive optical network. Background Art
[0002] A PON (Passive Optical Network) is a point-to-multipoint passive optical network. To mitigate the risk of single-point failures between the OLT and ONUs, the standard defines four PON redundancy methods.
[0003] When the two downstream PON ports of a single OLT (Optical Line Terminal) form a primary and backup PON relationship, Type B protection is implemented, providing redundant protection for each connected ONU (Optical Network Unit).
[0004] Although the fiber lengths from the ONU to the primary and backup PON ports of the OLT are set to be the same during network design, various factors during actual deployment can lead to discrepancies in the actual fiber lengths from the ONU to the primary and backup PON ports. EQD (equivalent distance) is a key technical parameter for distance measurement and timeslot synchronization in passive optical networks. The OLT calculates the EQD between itself and the ONU and uses it as a basis for calibrating and synchronizing upstream timeslots.
[0005] In TYPE B single-homing, if the OLT only measures the distance between one of the primary and backup PON ports and the ONU and calculates the EQD, then when the ONU switches to the other PON port and continues to use the EQD corresponding to the previous PON port, upstream timeslot misalignment may occur, causing data to arrive at the OLT PON port earlier or later. Summary of the Invention
[0006] The purpose of this application is to provide a method and device for switching equalized delay in a passive optical network, so that the ONU can switch to the corresponding PON port.
[0007] To achieve the above-mentioned objectives, the present application provides a method for switching balanced delay in a passive optical network, the method comprising: setting a first balanced delay information table for a first PON port and a second balanced delay information table for a second PON port; initializing the first PON port as a main PON port and the second PON port as a backup PON port; calculating the balanced delay between the first PON port and each online optical network unit (ONU), and recording the local balanced delay of the balanced delay table entry of each online ONU in the first balanced delay information table; synchronizing the balanced delay between the first PON port and each online optical network unit (ONU) to the second PON port, and recording the opposite-end balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table.
[0008] To achieve the above-mentioned objectives, the present application also provides a method for switching balanced delay in a passive optical network, the method comprising: setting a first balanced delay information table for a first PON port and a second balanced delay information table for a second PON port; initializing the first PON port as a main PON port and the second PON port as a backup PON port; calculating the balanced delay between the first PON port and each online optical network unit (ONU), and recording the local balanced delay of the balanced delay table entry of each online ONU in the first balanced delay information table; when the second PON port is switched to the main PON port; calculating the balanced delay between the second PON port and each online optical network unit (ONU), and recording the local balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table; and sending a second balanced delay modification message to each online ONU; wherein each of the balanced delay modification messages carries the local balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table.
[0009] The present application also provides a device for switching equalization delay in a passive optical network, the device including a processor and machine executable instructions stored in a memory, the processor executing the machine executable instructions to perform the following processing: setting a first equalization delay information table for a first PON port and a second equalization delay information table for a second PON port; initializing the first PON port as a main PON port and the second PON port as a backup PON port; calculating the equalization delay between the first PON port and each online optical network unit (ONU), and recording the local-end equalization delay of the equalization delay table entry of each online ONU in the first equalization delay information table; synchronizing the equalization delay between the first PON port and each online optical network unit (ONU) to the second PON port, and recording the opposite-end equalization delay of the equalization delay table entry of each online ONU in the second equalization delay information table.
[0010] The present application also provides a device for switching equalization delay in a passive optical network, the device including a processor and machine executable instructions stored in a memory, the processor executing the machine executable instructions to perform the following processing: setting a first equalization delay information table for a first PON port and a second equalization delay information table for a second PON port; initializing the first PON port as a main PON port and the second PON port as a backup PON port; calculating the equalization delay between the first PON port and each online optical network unit (ONU), and recording the equalization delay of the local end of the equalization delay table entry of each online ONU in the first equalization delay information table; when the second PON port is switched to the main PON port; calculating the equalization delay between the second PON port and each online optical network unit (ONU), and recording the equalization delay of the local end of the equalization delay table entry of each online ONU in the second equalization delay information table; and sending a second equalization delay modification message to each online ONU; wherein each of the equalization delay modification messages carries the equalization delay of the local end of the equalization delay table entry of each online ONU in the second equalization delay information table.
[0011] The beneficial effect of the present application is that it can adapt to the EQD difference between the primary and standby PON ports of the OLT device, the ONU does not store the EqD, and it is completely managed by the OLT, thereby reducing the switching delay: the standby port directly sends the pre-stored EqD, and there is no need to re-measure and calculate the EQD. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 Figure 2 shows a schematic diagram of a Type B single-homed architecture for a passive optical network.
[0013] Figure 2 The present application provides a flow chart of a method for switching equalized delay in a passive optical network according to an embodiment of the present invention;
[0014] Figure 3 Flowchart of Embodiment 2 of the method for switching equalized delay in a passive optical network provided by the present application;
[0015] Figure 4 Flowchart of Embodiment 3 of the method for switching equalized delay in a passive optical network provided by this application;
[0016] Figure 5 This is a flow chart of embodiment 4 of the method for switching equalized delay in a passive optical network provided by the present application. DETAILED DESCRIPTION
[0017] The present invention will be described in detail with reference to a plurality of examples shown in the accompanying drawings. In the following detailed description, a number of specific details are provided to provide a comprehensive understanding of the present invention. Known methods, steps, components, and circuits are not described in detail in the examples to avoid obscuring the understanding of the examples.
[0018] Among the terms used, the term "including" means including but not limited to; the term "containing" means including but not limited to; the terms "above," "within," and "below" are inclusive; the terms "greater than" and "less than" are exclusive. The term "based on" means based on at least a portion.
[0019] Figure 1 Figure 2 shows a schematic diagram of the Type B single-homing architecture of a passive optical network.
[0020] The two downstream PON ports 211 and 212 of the OLT 21 form a master-slave PON relationship, which constitutes Type B protection.
[0021] In Type B single-homing networking mode, the active PON port and the standby PON port of OLT 21 are both connected to the same optical splitter 22 , which has ONUs 23 to 29 connected to it, thus achieving redundant protection of the active and standby PON interfaces 211 and 212 .
[0022] Figure 2 The present application provides a flow chart of a method for switching equalized delay in a passive optical network. The method includes:
[0023] Step 201: The OLT sets a first equalization delay information table for a first PON port and a second equalization delay information table for a second PON port.
[0024] OLT 21 sets the equalization delay information table for PON port 211, as shown in Table 1-1:
[0025] Online ONU serial number Local end balanced delay Balanced delay at the other end
[0026] Table 1-1 OLT 21 sets the equalization delay information table for PON port 212, as shown in Table 2-1:
[0027] Online ONU serial number Local end balanced delay Balanced delay at the other end
[0028] Table 2-1
[0029] In the balanced delay information table 1-1 of the PON port 211 and the balanced delay information table 2-1 set for the PON port 212, the balanced delay table entry of each ONU is used to record the online ONU sequence number, the balanced delay measured at the local end, and the balanced delay synchronized with the opposite end.
[0030] In step 202, the OLT initializes the first PON port as the main PON port and the second PON port as the backup PON port.
[0031] The OLT 21 initializes the PON port 211 as a primary PON port and initializes the PON port 212 as a backup PON port.
[0032] Step 203 : Calculate the balanced delay between the first PON port and each online optical network unit (ONU), and record the local balanced delay of the balanced delay entry of each online ONU in the first balanced delay information table.
[0033] OLT21 detects that ONU23-26 has registered and is online. It measures the distance to ONU23-26 through PON port 211 and calculates the balanced delay of ONU23-26. The calculated delay is recorded in Table 1-1 as shown below.
[0034] Online ONU serial number Local end balanced delay Balanced delay at the other end ONU23 EQD21a ONU24 EQD21b ONU25 EQD21c ONU26 EQD21d
[0035] Table 1-1
[0036] In step 204, the OLT synchronizes the balanced delay between the first PON port and each online optical network unit (ONU) to the second PON port, and records the peer balanced delay of the balanced delay entry of each online ONU in the second balanced delay information table.
[0037] OLT 21 synchronizes the balanced delay of PON port 211 with each online optical network unit ONU 23-26 to PON port 212, and records the balanced delay of each online ONU in the balanced delay table 2-1 of PON port 212 as follows:
[0038]
[0039]
[0040] Table 2-1
[0041] Figure 3 This is a flow chart of a second embodiment of a method for switching equalized delay in a passive optical network provided by the present application. The method includes:
[0042] Step 301: The OLT switches the second PON port to the main PON port.
[0043] OLT 21 switches PON port 212 to the main PON port, determines that the local balanced delay in the balanced delay information table of PON port 212 is empty, and does not send a balanced delay modification message.
[0044] In step 302, the OLT calculates the balanced delay between the second PON port and each online optical network unit (ONU), and records the local balanced delay in the balanced delay entry of each online ONU in the second balanced delay information table.
[0045] OLT 21 measures the distance between ONUs 23 and 26 through PON port 212, calculates the equalization delay of ONUs 23 and 26, and records it in Table 2-1, as shown below.
[0046] Online ONU serial number Local end balanced delay Balanced delay at the other end ONU23 EQD22a EQD21a ONU24 EQD22b EQD21b ONU25 EQD22c EQD21c ONU26 EQD22d EQD21d
[0047] Table 2-1
[0048] Step 303: The OLT synchronizes the balanced delay between the second PON port and each online optical network unit (ONU) to the first PON port, and records the opposite-end balanced delay of the opposite-end delay entry of each online ONU in the first balanced delay information table.
[0049] OLT 21 synchronizes the balanced delay of PON port 212 with each online optical network unit ONU 23-26 to PON port 211, and records the balanced delay of each online ONU in the balanced delay table 1-1 of PON port 211 as follows:
[0050] Online ONU serial number Local end balanced delay Balanced delay at the other end ONU23 EQD21a EQD22a ONU24 EQD21b EQD22b ONU25 EQD21c EQD22c ONU26 EQD21d EQD22d
[0051] Table 1-1
[0052] In step 304, when the second PON port is switched to the primary PON port again, the OLT sends a second balanced delay modification message to each online ONU; wherein each balanced delay modification message carries the local balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table.
[0053] OLT 21 is switched to the main PON port again at PON port 212. It is determined that each entry in Table 2-1 records the local equalization delay, and an EQD Adjust Ploam message is sent to ONUs 23-26 corresponding to each entry. The Operation field of each EQD Adjust Ploam message carries an absolute override flag or a forced override flag, and the Delta EQD field value is the equalization delay value recorded for the local equalization delay of each entry in Table 2-1.
[0054] The OLT 21 sends an EQD Adjust (adjustment) Ploam (Physical Layer Operations, Administration and Maintenance) message to the upstream ONUs 23 - 26 respectively as an equalization delay modification message.
[0055] This application makes the following custom settings for the Operation field of the payload field of the EQD Adjust Ploam message, as shown in Table 3:
[0056]
[0057] When the Operation field carries the relative adjustment flag, the Delta EQD field value is the recorded EQD difference between the local EQD and the peer EQD. The MAC / PHY layer hardware of the ONU 23-26 adds the EQD difference carried in the Delta EQD field to the local EQD.
[0058] The Operation field carries an absolute override flag, and the Delta EQD field value is the recorded local EQD. The MAC / PHY layer hardware of the ONUs 23 to 26 unconditionally receives and applies the EQD value carried in the Delta EQD field.
[0059] The Operation field carries a forced overwrite flag, and the Delta EQD field value is the recorded local EQD. The MAC / PHY layer hardware of ONU23-26 first reads the current EQD register value and compares it with the value sent by the OLT. If a discrepancy is found, the value is modified.
[0060] Figure 4 This is a flow chart of a third embodiment of a method for switching equalized delay in a passive optical network provided by the present application. The method includes:
[0061] Step 401: The OLT switches the second PON port to the main PON port.
[0062] The OLT 21 switches the PON port 212 to the main PON port.
[0063] Step 402: The OLT calculates the balanced delay between the second PON port and each online optical network unit (ONU), and records the local balanced delay of the balanced delay entry of each online ONU in the second balanced delay information table.
[0064] OLT 21 measures the distance between ONUs 23 and 26 through PON port 212, calculates the equalization delay of ONUs 23 and 26, and records it in Table 2-1, as shown below.
[0065] Online ONU serial number Local end balanced delay Balanced delay at the other end ONU23 EQD22a EQD21a ONU24 EQD22b EQD21b ONU25 EQD22c EQD21c ONU26 EQD22d EQD21d
[0066] Table 2-1
[0067] Step 403: The OLT synchronizes the balanced delay between the second PON port and each online optical network unit (ONU) to the first PON port, and records the opposite-end balanced delay of the opposite-end delay entry of each online ONU in the first balanced delay information table.
[0068] OLT 21 synchronizes the balanced delay of PON port 212 with each online optical network unit ONU 23-26 to PON port 211, and records the balanced delay of each online ONU in the balanced delay table 1-1 of PON port 211 as follows:
[0069]
[0070]
[0071] Table 1-1
[0072] Step 404: traverse the equalization delay table entry of each online ONU in the second equalization delay information table;
[0073] OLT 21 traverses the equalization delay table entry of each online ONU in Table 2-1.
[0074] Step 405: Determine whether the difference between the equalization delay of the local end and the equalization delay of the remote end is greater than the specified equalization delay range; if so, execute step 406; if not, execute step 407;
[0075] OLT21 calculates the balanced delay difference by subtracting the local balanced delay from the peer balanced delay in the balanced delay table entry of each online ONU being traversed; and compares the calculated balanced delay difference with the set balanced delay difference range; the balanced delay difference range can be set based on experience.
[0076] Step 406: Send a second balanced delay modification message; wherein each second balanced delay modification message carries the local balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table.
[0077] OLT 21 sends an EQD Adjust Ploam message. When the Operation field carries the relative adjustment flag, the Delta EQD field carries the recorded equalization delay difference. When any ONU 23-26 receives the EQD Adjust Ploam message, the MAC / PHY layer hardware of that ONU adds the equalization delay difference carried in the Delta EQD field to the local EQD.
[0078] Step 407: The equalization delay of the corresponding online ONU is not modified.
[0079] In the above embodiments 1-3, if OLT21 is restarted, after the restart is completed, the balanced delay of the opposite end of the balanced delay table entry of each online ONU is read from the balanced delay information table of the main PON port and cached; and the local balanced delay and the opposite end balanced delay of the balanced delay table entry of each online ONU are read from the balanced delay information table of the standby PON port and cached.
[0080] Figure 5 This is a flow chart of a fourth embodiment of a method for switching equalized delay in a passive optical network provided by the present application. The method includes:
[0081] Step 501, setting a first equalization delay information table of a first PON port and a second equalization delay information table of a second PON port;
[0082] OLT 21 sets the equalization delay information table for PON port 211, as shown in Table 3-1:
[0083] Online ONU serial number Local end balanced delay
[0084] Table 3-1 OLT 21 sets the equalization delay information table for PON port 212, as shown in Table 4-1:
[0085] Online ONU serial number Local end balanced delay
[0086] Table 4-1
[0087] In step 502, the OLT initializes the first PON port as the main PON port and the second PON port as the backup PON port.
[0088] The OLT 21 initializes the PON port 211 as a primary PON port and initializes the PON port 212 as a backup PON port.
[0089] In step 503, the OLT calculates the balanced delay between the first PON port and each online optical network unit (ONU), and records the local balanced delay of the balanced delay entry of each online ONU in the first balanced delay information table.
[0090] OLT21 detects that ONU23-26 has registered and is online. It measures the distance of ONU23-26 through PON port 211 and calculates the balanced delay of ONU23-26. The calculated delay is recorded in Table 3-1 as shown below.
[0091] Online ONU serial number Local end balanced delay ONU23 EQD21a ONU24 EQD21b ONU25 EQD21c ONU26 EQD21d
[0092] Table 3-1
[0093] Step 504: The OLT switches the second PON port to the primary PON port.
[0094] The OLT 21 switches the PON port 212 to the main PON port.
[0095] Step 505: The OLT calculates the balanced delay between the second PON port and each online optical network unit (ONU), and records the local balanced delay of the balanced delay entry of each online ONU in the second balanced delay information table.
[0096] OLT21 port measures the distance between ONU23-26 through PON port 221, calculates the equalization delay of ONU23-26, and records it in Table 4-1 as shown below.
[0097] Online ONU serial number Local end balanced delay ONU23 EQD22a ONU24 EQD22b ONU25 EQD22c ONU26 EQD22d
[0098] Table 4-1
[0099] In step 506, the OLT sends a second balanced delay modification message to each online ONU. Each balanced delay modification message carries the local balanced delay of the balanced delay entry of each online ONU in the second balanced delay information table.
[0100] The load Operation field of the EQD Adjust Ploam message sent by OLT 21 carries the absolute override or forced override flag; the Delta EQD field value is the recorded local equalization delay.
[0101] The Operation field carries an absolute override flag, and the Delta EQD field value is the recorded local EQD. The MAC / PHY layer hardware of the ONUs 23 to 26 unconditionally receives and applies the EQD value carried in the Delta EQD field.
[0102] The Operation field carries a forced overwrite flag, and the Delta EQD field value is the recorded local EQD. The MAC / PHY layer hardware of ONU23-26 first reads the current EQD register value and compares it with the value sent by the OLT. If a discrepancy is found, the value is modified.
[0103] The present application also provides a device for switching equalization delay in a passive optical network, the device comprising a processor and machine executable instructions stored in a memory, the processor executing the machine executable instructions to implement Figure 1 、 Figure 2-Figure 4 The embodiment shown.
[0104] The present application also provides a device for switching equalized delay in a passive optical network, the device comprising a processor and machine executable instructions stored in a memory, the processor executing the machine executable instructions to perform Figure 1 and Figure 5 The embodiment shown.
[0105] In this application, a machine-readable storage medium may be any electronic, magnetic, optical, or other physical storage device for storing or containing information (e.g., executable instructions, data, etc.). For example, any machine-readable storage medium herein may be any type of random access memory (RAM), volatile memory, non-volatile memory, flash memory, storage drive (e.g., hard drive), solid-state drive, any type of storage optical disc (e.g., optical disc, DVD, etc.), and similar devices, or a combination thereof. In addition, any machine-readable storage medium herein may be a non-transitory machine-readable storage medium.
[0106] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.
Claims
1. A method for switching equalized delay in a passive optical network, characterized in that: The method comprises, Setting a first equalization delay information table for the first PON port and a second equalization delay information table for the second PON port; Initialize the first PON port as a main PON port and the second PON port as a backup PON port; Calculate the balanced delay between the first PON port and each online optical network unit (ONU), and record the local balanced delay of the balanced delay entry of each online ONU in the first balanced delay information table; Synchronize the balanced delay between the first PON port and each online optical network unit ONU to the second PON port, and record the opposite end balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table.
2. The method according to claim 1, characterized in that The method further comprises, When the second PON port is switched to the main PON port; Calculate the balanced delay between the second PON port and each online optical network unit ONU, and record the local balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table; Synchronize the balanced delay between the second PON port and each online optical network unit (ONU) to the first PON port, and record the opposite-end balanced delay of the opposite-end delay entry of each online ONU in the first balanced delay information table; A second balanced delay modification message is sent to each online ONU; wherein each balanced delay modification message carries the local balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table.
3. The method according to claim 1, characterized in that The method further comprises, When the second PON port is switched to the main PON port; Calculate the balanced delay between the second PON port and each online optical network unit ONU, and record the local balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table; Determine that the second PON port is switched to the main PON port again, synchronize the balanced delay between the second PON port and each online optical network unit (ONU) to the first PON port, and record the opposite end balanced delay of the opposite end delay entry of each online ONU in the first balanced delay information table; Traversing the balanced delay table entry of each online ONU in the second balanced delay information table; When the balanced delay difference between the local balanced delay and the peer balanced delay in the balanced delay table entry of any of the online ONUs is greater than the specified balanced delay range, a second balanced delay modification message is sent to the corresponding online ONU; wherein each of the second balanced delay modification messages carries the balanced delay difference between the local balanced delay and the peer balanced delay; or When the difference between the local balanced delay and the opposite balanced delay in the balanced delay table entry of any online ONU is smaller than the specified balanced delay range, the balanced delay of the corresponding online ONU is not adjusted.
4. The method according to claim 3, characterized in that The method further comprises, Make sure the device has restarted. Read the balanced delay information table of the main PON port and cache the balanced delay of the opposite end of each of the online ONUs; The local end balanced delay and the peer end balanced delay of each online ONU balanced delay entry in the balanced delay information table of the standby PON port are read and cached.
5. The method according to claim 1, 2 or 4, characterized in that: The first equalization delay modification message and the second equalization delay modification message carry an absolute override flag, so that the MAC layer or the physical layer of each online ONU is forced to apply the equalization delay carried by the first equalization delay modification message and the second equalization delay modification message; or, The first balanced delay modification message and the second balanced delay modification message carry a forced overwrite mark, so that the MAC layer or physical layer of each online ONU compares the locally recorded balanced delay and finds that it is different from the balanced delay carried by the first balanced delay modification message and the second balanced delay modification message, and then updates the locally recorded balanced delay.
6. The method according to claim 3, characterized in that The first balanced delay modification message and the second balanced delay modification message carry a relative adjustment mark and a balanced delay difference between the balanced delay of the local end and the balanced delay of the opposite end, so that the MAC layer or physical layer of each online ONU adds the locally recorded balanced delay to the balanced difference carried by the first balanced delay modification message and the second balanced delay modification message to update the locally recorded balanced delay.
7. A method for switching equalized delay in a passive optical network, characterized in that: The method comprises, Setting a first equalization delay information table for the first PON port and a second equalization delay information table for the second PON port; Initialize the first PON port as a main PON port and the second PON port as a backup PON port; Calculate the balanced delay between the first PON port and each online optical network unit (ONU), and record the local balanced delay of the balanced delay entry of each online ONU in the first balanced delay information table; When the second PON port is switched to the main PON port; Calculate the balanced delay between the second PON port and each online optical network unit ONU, and record the local balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table; A second balanced delay modification message is sent to each online ONU; wherein each balanced delay modification message carries the local balanced delay of the balanced delay table entry of each online ONU in the second balanced delay information table.
8. The method according to claim 7, characterized in that The first equalization delay modification message and the second equalization delay modification message carry an absolute override flag, so that the MAC layer or the physical layer of each online ONU is forced to apply the equalization delay carried by the first equalization delay modification message and the second equalization delay modification message; or The first balanced delay modification message and the second balanced delay modification message carry a forced overwrite mark, so that the MAC layer or physical layer of each online ONU compares the locally recorded balanced delay and finds that it is different from the balanced delay carried by the first balanced delay modification message and the second balanced delay modification message, and then updates the locally recorded balanced delay.
9. A device for switching equalized delay in a passive optical network, characterized in that: The device includes a processor and machine-executable instructions stored in a memory, and the processor executes the machine-executable instructions to perform any one of the methods of claims 1-6.
10. A device for switching equalized delay in a passive optical network, characterized in that: The device includes a processor and machine-executable instructions stored in a memory, and the processor executes the machine-executable instructions to perform any one of the methods of claims 7-8.