Method and equipment for quickly recovering service of optical access network

Abstract

The invention provides a method and equipment for quickly recovering services of an optical access network. The method comprises the following steps: detecting that a main path of an optical access network is switched into a standby path connected with a PON port of the equipment; all MAC address table entries learned in each synchronized virtual local area network (VLAN) on the equipment are deleted; and broadcasting the received optical signal frame in the virtual local area network to enable the downstream equipment to refresh the MAC address table item through the port for receiving the downlink data message on the standby path, thereby completing the rapid re-learning of the MAC address table item, and setting the non-refreshed ARP table item to use the output port for re-learning the MAC address table item to rapidly recover the three-layer flow forwarding.

Description

Technical Field

[0001] This application relates to optical access network technology, specifically a method and device for rapidly restoring services in an optical access network. Background Technology

[0002] In PON networks, the Type B dual-homing architecture provides a redundant OLT (Optical Line Terminal) protection mechanism. Each ONU (Optical Network Unit) connects to a fiber optic backup group consisting of two OLTs via a splitter with a splitting ratio of 2:N.

[0003] In a fiber optic backup group, the primary and backup OLT devices synchronize data via a TCP connection. The primary OLT port of the primary OLT device performs optical signal forwarding. When the primary OLT device is short-circuited to the backbone fiber of the splitter or the PON port is disconnected (down), the primary and backup OLTs in the fiber optic backup group will automatically switch over, with the backup OLT becoming the new primary OLT and forwarding optical signals based on the synchronized data. However, because the MAC address and ARP entries of the accessed terminals are not immediately updated, the downlink terminal traffic is sent to the faulty path before the switchover, resulting in forwarding failure.

[0004] FTTR (Fiber To The Room) networks are increasingly incorporating redundant networking configurations such as dual OLTs and dual uplinks. In these redundant FTTR scenarios, when the primary path of the uplink OLT switches to the backup path, the same problem arises: downlink terminals send packets to the path before the switch, leading to forwarding failure. Summary of the Invention

[0005] The purpose of this application is to provide a method and device for quickly restoring services in an optical access network, which quickly restores Layer 3 traffic forwarding by setting ARP entries to use the outgoing ports of relearned MAC address entries.

[0006] To achieve the above objectives, this application provides a method for quickly restoring services in an optical access network. The method includes detecting that the primary path of the optical access network has been switched to a backup path connected to the PON port of this device; deleting all MAC address entries learned in each virtual local area network (VLAN) that have been synchronized on this device; and broadcasting the received optical signal frames within the corresponding VLAN, so that downstream devices refresh the MAC address entries on the ports that receive downlink data packets on the backup path, thereby completing the rapid relearning of MAC address entries.

[0007] To achieve the above objectives, this application also provides a device for rapidly restoring services in an optical access network. The device includes a processor, a machine-readable storage medium, a switching chip, and a network interface. The processor executes machine-executable instructions recorded on the machine-readable storage medium to perform the following operations: detecting a switch from the primary path of the optical access network to a backup path connected to the device's PON port; deleting all MAC address entries already synchronized within each virtual local area network (VLAN) on the device; and broadcasting received optical signal frames within their respective VLANs, enabling downstream devices to refresh their MAC address entries on the ports receiving downlink data packets on the backup path, thereby completing the rapid relearning of MAC address entries.

[0008] The beneficial effect of this application is that, during the primary and backup path switching of the optical access network, by deleting the original MAC address table entries and broadcasting them in the virtual local area network, the downstream devices are prompted to quickly relearn the MAC address based on the backup path port, thereby improving the service recovery speed of the optical access network during the primary and backup path switching. Attached Figure Description

[0009] Figure 1 A flowchart illustrating an embodiment of a method for rapidly restoring services in an optical access network provided in this application; Figure 2 A schematic diagram illustrating an embodiment of rapid recovery of Layer 2 service traffic provided in this application; Figure 3 A schematic diagram of an embodiment of rapid recovery of three-layer service traffic provided in this application; Figure 4 This is a schematic flowchart illustrating an embodiment of a device for quickly restoring services in an optical access network, as provided in this application. Detailed Implementation

[0010] The following detailed description will be provided with reference to several examples illustrated in the accompanying figures. In this detailed description, numerous specific details are used to provide a comprehensive understanding of the present application. Known methods, steps, components, and circuits are not described in detail in the examples to avoid obscuring their meaning.

[0011] In the terminology 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" include the number itself; the terms "greater than" and "less than" mean not including the number itself. The term "based on" means based on at least a portion of them.

[0012] Figure 1 This application provides a flowchart of an embodiment of a method for quickly restoring services in an optical access network. This embodiment includes... Step 101: It is detected that the primary path of the optical access network has been switched to the backup path connected by the PON port of this device; Step 102: Delete all MAC address entries learned in each virtual LAN VLAN that have been synchronized on this device; Step 103: Optical signal frames for which no matching MAC address entry is found in the MAC address table are broadcast within their respective virtual LANs.

[0013] Figure 1 The beneficial effect of this embodiment is that, during the primary and backup path switching of the optical access network, by deleting the original MAC address entries and broadcasting them in the virtual local area network, downstream devices are prompted to quickly relearn the MAC address based on the backup path port, thereby improving the service recovery speed of the optical access network during the primary and backup path switching.

[0014] Figure 2 This is a schematic diagram of an embodiment of rapid recovery of Layer 2 service traffic provided in this application.

[0015] A fiber optic backup group consists of one primary OLT (Optical Line Terminal) and one backup OLT. The primary and backup OLTs are located in a loop-free STP (Spanning Tree Protocol) network with switch S1. Within the STP loop-free network, switch S1 sends downlink unicast / broadcast data packets to the primary OLT.

[0016] In the fiber optic backup group, the PON port of the primary optical line terminal (OLT1) is in active mode, encapsulating downlink unicast / broadcast data packets into optical signal frames and sending them to the optical access network via the primary path. The PON port of the backup OLT is in protected mode and does not forward downlink unicast / broadcast data packets; thus, in the fiber optic backup group, only the primary path forwards data to the optical access network.

[0017] When the primary OLT device detects a loss of optical signal at its PON port in the optical access network, it sends a primary path switch notification (201) to the backup OLT. The backup OLT then detects that the primary path to the optical access network has been switched to the backup path connected to its PON port based on the backup path switch notification (201).

[0018] The standby OLT deletes all MAC address entries in the MAC address table of each Virtual Local Area Network (VLAN) on this device; When the backup OLT receives optical signal frame 202 in VLAN 10, it performs a lookup in the MAC address table of VLAN 10 and finds no matching MAC address entry for the destination MAC address of optical signal frame 202.

[0019] The backup OLT will broadcast optical signal frame 202 to other ONU devices, such as ONU N devices and ONU M devices, in its VLAN 10.

[0020] Figure 2 The beneficial effect of this embodiment is that after the backup OLT device deletes the MAC addresses in each VLAN carried by the backup path, the backup OLT forwards Layer 2 traffic but cannot find the corresponding destination MAC address entry in the packet's table. Although broadcasting within the corresponding VLAN will waste some bandwidth, it will not cause packet loss. Once the destination device receives the broadcast optical signal frame within the VLAN, it will refresh the MAC address table entry. Furthermore, based on the refreshed MAC address table entry, the destination device first sends a response optical signal frame to the backup OLT device, and the backup OLT device learns the correct PON port corresponding to the device's MAC address. Subsequently, the backup OLT device, based on the newly learned correct PON port, unicasts the optical signal frame destined for the destination device within the VLAN without needing to broadcast it again.

[0021] Figure 3 This is a schematic diagram of an embodiment of rapid recovery of three-layer service traffic provided in this application.

[0022] After receiving the notification message for the primary / backup link switchover of the standby OLT device, the device sets the hardware entry of the ARP table entry on this device to use the MAC table entry's output port flag, thereby setting the output port of each ARP entry to the output port of the associated MAC address entry.

[0023] The standby OLT device receives Ethernet packet 31 from switch S1 and determines that the destination MAC address of Ethernet packet 31 is its own MAC address. The standby OLT device looks up the ARP entry in the ARP table based on the inner IP address of Ethernet packet 31. It then modifies the source MAC address and destination MAC address of Ethernet packet 31 to its own MAC address and the MAC address of the ARP entry, respectively.

[0024] The backup OLT device uses the MAC address flag in the ARP entry to look up the associated MAC address entry in the MAC address table of VLAN 10. The backup OLT device encapsulates the Layer 3 forwarded Ethernet packet 31 into an optical signal frame 311 and sends it to ONU device 1 through the associated MAC address entry's output port.

[0025] The standby OLT device receives Ethernet packet 32 ​​from switch S1 and determines that the destination MAC address of Ethernet packet 32 ​​is its own MAC address. The standby OLT device looks up the ARP entry in the ARP table based on the inner IP address of Ethernet packet 32. It then modifies the source MAC address and destination MAC address of Ethernet packet 32 ​​to its own MAC address and the MAC address of the ARP entry, respectively.

[0026] The backup OLT device, based on the outgoing port flag of the MAC address entry in the ARP table, did not find the associated MAC address entry in the MAC address table of VLAN 10. The backup OLT device encapsulates the Layer 3 forwarded Ethernet packet 32 ​​into an optical signal frame 321, and broadcasts the optical signal frame 321 to ONU device 1, ONU device N, and ONU device M within VLAN 10.

[0027] When the backup OLT device receives an ARP request or response message through any PON port, it finds a matching ARP entry based on the sender's IP address of the ARP request or response message, relearns the outgoing port of the ARP entry, deletes the MAC address flag of this ARP entry, and then forwards Layer 3 traffic through the outgoing port of the relearned ARP entry.

[0028] Alternatively, if the backup OLT device does not find a matching ARP entry in its ARP table based on the sender's IP address of the ARP request or response message, it will proceed with the normal ARP entry learning process.

[0029] This application Figure 2 , Figure 3 The example shown is also applicable to all-optical access networks built on the FTTR fiber-to-the-room solution, but is not limited to FTTR application scenarios.

[0030] Figure 4 This is a schematic flowchart illustrating an embodiment of a device for quickly restoring services in an optical access network, as provided in this application. The device 40 includes a processor 41, a machine-readable storage medium 42, a switching chip 43, and a network interface 44.

[0031] The processor 41 executes the machine-executable instructions recorded in the machine-readable storage medium 42 to perform the following operations: detects that the primary path of the optical access network has been switched to the backup path connected to the PON port of this device; deletes all MAC address entries learned in each virtual local area network (VLAN) that have been synchronized on this device; and broadcasts the received optical signal frames in the VLAN to which they belong, so that downstream devices can refresh the MAC address entries on the port that receives downlink data packets on the backup path, thereby completing the rapid relearning of MAC address entries.

[0032] The processor 41, by executing machine-executable instructions recorded in the machine-readable storage medium 42, also performs the following operations: identifies the MAC address in each learned ARP entry and associates it with the MAC address entry in the MAC address table; and sets the output port of each learned ARP entry to the PON port of the associated MAC address entry.

[0033] Processor 41, by executing machine-executable instructions recorded in machine-readable storage medium 42, also performs the following operations: based on the destination IP address of the Ethernet packet to be forwarded at Layer 3, searches for a matching ARP entry in the ARP table; using the MAC address of this device as the source MAC address and the MAC address of the found ARP entry as the destination MAC address, modifies the source MAC address and destination MAC address of the Ethernet packet to be forwarded at Layer 3; searches for a matching MAC address entry for the modified destination MAC address of the Ethernet packet in the MAC address table; encapsulates the modified Ethernet packet into an optical signal frame; and sends the optical signal frame through the PON port of the found MAC address entry.

[0034] Processor 41, by executing machine-executable instructions recorded in machine-readable storage medium 42, also performs the following operations: based on the destination IP address of the Ethernet packet to be forwarded at Layer 3, searches for a matching ARP entry in the ARP table; using the MAC address of this device as the source MAC address and the MAC address of the found ARP entry as the destination MAC address, modifies the source MAC address and destination MAC address of the Ethernet packet to be forwarded at Layer 3; in the MAC address table, no matching MAC address entry for the destination MAC address of the modified Ethernet packet is found; encapsulates the modified Ethernet packet into an optical signal frame; and broadcasts the optical signal frame to all PON ports within the VLAN to which the optical signal frame belongs.

[0035] Processor 41, by executing machine-executable instructions recorded in machine-readable storage medium 42, also performs the following operations: receiving ARP protocol messages through any PON port; searching the ARP table for an ARP entry that matches the sender's IP address based on the ARP protocol message, and modifying the output port of that ARP entry to the port of the ARP protocol message; or, if no ARP entry matching the sender's IP address based on the ARP protocol message is found in the ARP table, learning a new ARP entry based on the sender's IP address, sender's MAC address, and receiver port of the ARP protocol message.

[0036] In this application, a machine-readable storage medium can be any electronic, magnetic, optical, or other physical storage device used to store or contain information (such as executable instructions, data, etc.). For example, any machine-readable storage medium described herein can be any type of random access memory (RAM), volatile memory, non-volatile memory, flash memory, storage drive (such as a hard disk drive), solid-state drive, any type of optical disc (such as an optical disc, DVD, etc.), and similar devices, or combinations thereof. Furthermore, any machine-readable storage medium described herein can be a non-transitory machine-readable storage medium.

[0037] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for rapidly restoring services in an optical access network, characterized in that, The method includes, The primary path of the optical access network has been switched to a backup path connected to the PON port of this device; Delete all MAC address entries learned in each virtual LAN VLAN that have been synchronized on this device; Optical signal frames for which no matching MAC address entry is found in the MAC address table will be broadcast within their respective virtual LANs.

2. The method according to claim 1, characterized in that, The method also includes, Identify the MAC address in each learned ARP entry and associate it with the corresponding MAC address entry in the MAC address table; Set the output port of each learned ARP entry to the PON port associated with the MAC address entry.

3. The method according to claim 2, characterized in that, The method also includes, Based on the destination IP address of the Ethernet packet to be forwarded at Layer 3, a matching ARP entry is found in the ARP table; Using the MAC address of this device as the source MAC address and the MAC address of the found ARP table entry as the destination MAC address, modify the source MAC address and destination MAC address of the Ethernet packet to be forwarded at Layer 3. In the MAC address table, find the matching MAC address entry for the destination MAC address of the modified Ethernet packet; The modified Ethernet packet is encapsulated into an optical signal frame; The optical signal frame is sent through the PON port of the found MAC address entry.

4. The method according to claim 2, characterized in that, The method also includes, Based on the destination IP address of the Ethernet packet to be forwarded at Layer 3, a matching ARP entry is found in the ARP table; Using the MAC address of this device as the source MAC address and the MAC address of the found ARP table entry as the destination MAC address, modify the source MAC address and destination MAC address of the Ethernet packet to be forwarded at Layer 3. No matching MAC address entry for the destination MAC address of the modified Ethernet packet was found in the MAC address table. The modified Ethernet packet is encapsulated into an optical signal frame; The optical signal frame is broadcast on all PON ports within the VLAN to which the optical signal frame belongs.

5. The method according to claim 3 or 4, characterized in that, The method also includes, Receive ARP protocol messages through any PON port; In the ARP table, find an ARP entry that matches the IP address of the sender of the ARP protocol message, and change the outgoing port of the ARP entry to the port of the ARP protocol message; or, If no matching ARP entry is found in the ARP table based on the sender's IP address of the ARP protocol message, a new ARP entry will be learned based on the sender's IP address, sender's MAC address, and receiver port of the ARP protocol message.

6. An apparatus for rapidly restoring services in an optical access network, the apparatus comprising a processor, a machine-readable storage medium, a switching chip, and a network interface; characterized in that, The processor performs the following operations by executing machine-executable instructions recorded on the machine-readable storage medium. The primary path of the optical access network has been switched to a backup path connected to the PON port of this device; Delete all MAC address entries learned in each virtual LAN VLAN that have been synchronized on this device; The received optical signal frames are broadcast within the virtual local area network, so that downstream devices can refresh their MAC address table entries on the ports that receive the downlink data packets on the backup path, thereby completing the rapid relearning of MAC address table entries.

7. The device according to claim 6, characterized in that, The processor also performs the following operations by executing machine-executable instructions recorded on the machine-readable storage medium: Identify the MAC address in each learned ARP entry and associate it with the corresponding MAC address entry in the MAC address table; Set the output port of each learned ARP entry to the PON port associated with the MAC address entry.

8. The device according to claim 7, characterized in that, The processor also performs the following operations by executing machine-executable instructions recorded on the machine-readable storage medium: Based on the destination IP address of the Ethernet packet to be forwarded at Layer 3, a matching ARP entry is found in the ARP table; Using the MAC address of this device as the source MAC address and the MAC address of the found ARP table entry as the destination MAC address, modify the source MAC address and destination MAC address of the Ethernet packet to be forwarded at Layer 3. In the MAC address table, find the matching MAC address entry for the destination MAC address of the modified Ethernet packet; The modified Ethernet packet is encapsulated into an optical signal frame; The optical signal frame is sent through the PON port of the found MAC address entry.

9. The device according to claim 7, characterized in that, The processor also performs the following operations by executing machine-executable instructions recorded on the machine-readable storage medium: Based on the destination IP address of the Ethernet packet to be forwarded at Layer 3, a matching ARP entry is found in the ARP table; Using the MAC address of this device as the source MAC address and the MAC address of the found ARP table entry as the destination MAC address, modify the source MAC address and destination MAC address of the Ethernet packet to be forwarded at Layer 3. No matching MAC address entry for the destination MAC address of the modified Ethernet packet was found in the MAC address table. The modified Ethernet packet is encapsulated into an optical signal frame; The optical signal frame is broadcast on all PON ports within the VLAN to which the optical signal frame belongs.

10. The device according to claim 8 or 9, characterized in that, The processor also performs the following operations by executing machine-executable instructions recorded on the machine-readable storage medium: Receive ARP protocol messages through any PON port; In the ARP table, find an ARP entry that matches the IP address of the sender of the ARP protocol message, and change the outgoing port of the ARP entry to the port of the ARP protocol message; Alternatively, if no matching ARP entry is found in the ARP table based on the sender's IP address of the ARP protocol message, a new ARP entry is learned based on the sender's IP address, sender's MAC address, and receiver port of the ARP protocol message.

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