A method and apparatus for accelerating optical circuit switched service restoration

Abstract

The application discloses a method and device for accelerating optical circuit switching service recovery, and relates to the technical field of optical communication. The method comprises the following steps: when optical path switching is needed, informing a source port and a destination port to enter a fast link establishment state before switching an optical path connection; the source port sends an alignment mark at a first sending interval; the destination port detects at the first sending interval; the first sending interval is smaller than a normal working interval. The optical switching unit is controlled to perform the optical path switching; after the switching, the destination port detects the alignment mark at the first sending interval; after a preset number of valid alignment marks are detected, the link establishment is confirmed; then, both ends return to the normal working state. The application can solve the problem that the service link establishment recovery time is long in the related art during optical switching, the sending interval and the detection interval of the alignment mark are shortened, the link establishment time of the physical coding sublayer is shortened, and the available bandwidth utilization of the optical circuit switching system is improved.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a method and apparatus for accelerating the recovery of optical circuit-switched services. Background Technology

[0002] In optical circuit switching (OCS) technology, each inlet or outlet can only establish a single optical path at any given time, with a one-to-one optical path connection between each inlet and outlet port. When handling low-latency, low-data-volume scenarios, frequent optical path reconfiguration is required, with reconfiguration times ranging from microseconds to tens of milliseconds. During OCS, the phase of both the clock and data alignment flags changes, inevitably leading to port re-establishment. Related technologies exhibit long service link establishment and recovery times during OCS, resulting in low utilization of the available bandwidth in the optical switching system.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] This application provides a method and apparatus for accelerating the recovery of optical circuit switching services, shortening the service link establishment time during OCS optical handover, and effectively accelerating port link establishment efficiency.

[0005] To solve the above-mentioned technical problems, this application provides the following technical solution: This application provides a method for accelerating the recovery of optical circuit-switched services, including: When an optical path switching requirement is determined, a state switching command is sent to the source port and destination port corresponding to the physical layer optical link to be established before switching the optical path connection, so that the source port transmitting side and the destination port receiving side enter the fast link establishment state. In fast link establishment mode, the source port transmitting side sends an alignment mark to the destination port receiving side according to a first transmission interval, and the destination port receiving side detects the alignment mark according to the first transmission interval; the first transmission interval is less than the second transmission interval used by the destination port in normal working mode. The optical switching unit is controlled to perform an optical path switching operation to establish a physical layer optical link between the source port and the destination port; After the optical path switching operation is completed, the receiving side of the destination port detects the alignment mark from the transmitting side of the source port according to the first transmission interval, and determines that the link establishment is completed after detecting a preset number of valid alignment marks; after the link establishment is completed, the receiving side of the destination port and the transmitting side of the source port switch from the fast link establishment state to the normal operation state.

[0006] Another aspect of this application provides an apparatus for accelerating the recovery of optical circuit-switched services, including an inbound service end, an optical circuit-switching controller, an optical circuit-switching unit, and an outbound service end; The link establishment accelerator at the inbound service end is connected to the optical circuit switching controller to receive state switching instructions and return the link establishment completion time; the physical medium connection sublayer or physical medium related sublayer at the inbound service end is connected to the optical circuit switching unit through a photoelectric converter. The optical circuit switching unit is connected to the optical circuit switching controller and is used to perform optical path switching operation after receiving a state switching command; The link establishment accelerator for the outgoing service end is connected to the optical circuit switching controller, and is used to receive state switching instructions and return the link establishment completion time; the physical medium connection sublayer or physical medium related sublayer for the outgoing service end is connected to the optical circuit switching unit through a photoelectric converter. The optical circuit switching controller is used to implement the steps of the above-described method for accelerating the recovery of optical circuit switching services when executing the computer program.

[0007] The advantage of the technical solution provided in this application is that, before the optical path switching operation is performed, the source port transmitting side and the destination port receiving side pre-enter a fast link establishment state with a first transmission interval for sending and receiving alignment marks. Since the first transmission interval is less than the second transmission interval used in normal operation, the destination port receiving side detects the alignment marks according to the first transmission interval after the optical path switching is completed. This shortens the time required for the destination port receiving side to search for and align to the alignment marks after the optical path switching is completed. This allows the destination port receiving side to continuously detect a preset number of valid alignment marks in a shorter time, thereby reducing the waiting time between the completion of the optical path switching and the detection of a preset number of valid alignment marks by the destination port receiving side to determine the completion of link establishment. This shortens the time occupied by the entire physical coding sublayer link establishment process, shortens the overall service recovery time during optical circuit switching, increases the effective time window available for transmitting service data per unit time in the optical circuit switching system, and improves the utilization rate of available bandwidth. Furthermore, by sending a status recovery notification to the optical circuit switching controller after link establishment is completed, the optical circuit switching controller determines the service recovery time based on the link establishment success time and the start link establishment time, and determines the switching efficiency based on the service recovery time and time slot duration. This allows for accurate assessment of the actual time consumption of each optical path switch, thereby optimizing optical path scheduling parameters and improving the available bandwidth utilization of the optical switching system. In addition, this application also provides a corresponding implementation apparatus for accelerating optical circuit switching service recovery, which has corresponding advantages.

[0008] The technical features mentioned above, those to be mentioned below, and those shown individually in the accompanying drawings can be arbitrarily combined, as long as the combined technical features are not contradictory. All feasible combinations of features are the technical content explicitly described in this application. Any one of the multiple sub-features contained in the same statement can be applied independently, without necessarily being applied together with other sub-features.

[0009] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A schematic diagram illustrating OCS switching efficiency; Figure 2 A flowchart illustrating a method for accelerating the recovery of optical circuit-switched services provided in this application; Figure 3 A comparative diagram illustrating the effects of the accelerated optical circuit-switched service recovery method provided in this application; Figure 4 A flowchart illustrating another method for accelerating the recovery of optical circuit-switched services provided in this application; Figure 5 A structural framework diagram of an exemplary embodiment of the apparatus for accelerating the recovery of optical circuit-switched services provided in this application; Figure 6 A schematic diagram of the framework of the apparatus for accelerating the recovery of optical circuit-switched services provided in this application in an exemplary application scenario; Figure 7 A schematic diagram illustrating the workflow of an OCS controller in an exemplary application scenario provided in this application; Figure 8 A schematic diagram illustrating the interaction during optical circuit switching in an exemplary application scenario provided in this application; Figure 9 This application provides a timing diagram of the OCS handover process in an exemplary application scenario. Figure 10 A schematic diagram of a typical high-speed port fast AM cycle and standard AM cycle in an exemplary application scenario provided in this application; Figure 11This application provides a schematic diagram of a 100G high-speed port fast AM cycle and a standard AM cycle in an exemplary application scenario. Detailed Implementation

[0012] To enable those skilled in the art to better understand the technical solutions of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The terms "first," "second," "third," "fourth," etc., used in the specification and the aforementioned drawings are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. The term "exemplary" means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0013] In principle, OCS (Optical Circuit Switching) allows only a single optical path to be established at any given time for each inlet or outlet; that is, each inlet and outlet port uses a one-to-one optical path connection. When handling low-latency, low-data-volume scenarios, frequent optical path reconfiguration is required. Typical reconfiguration times range from microseconds to tens of milliseconds. When the configuration cycle is comparable to the reconfiguration latency, overall transmission efficiency decreases.

[0014] During optical circuit switching (OCS) handover, the phase of both the clock and data alignment identifiers changes, inevitably leading to port re-establishment. The entire service recovery time includes OCS reconfiguration time, PMA (Physical Medium Attachment) layer training and clock locking time, and PCS (Physical Coding Sublayer) layer time. The PCS layer includes FEC (Forward Error Correction) locking and lane de-skew time. OCS implementations include MEMS (Micro-Electro-Mechanical System), PLC (Planar Lightwave Circuit), and WSS (Wavelength Selective Switch), with handover times ranging from microseconds to tens of milliseconds. With the maturation of fast handover technology, OCS handover times are expected to reach sub-microsecond levels, with PMA training and clock locking times in the sub-microsecond range and PMA link establishment time in the millisecond range. Figure 1 As shown, the key bottleneck in the entire process lies in the chain establishment time of the physical coding sublayer.

[0015] The physical coding sublayer link establishment function is defined by the 802.3 standard, including the processing time for synchronization header locking, AM (Alignment Marker) locking, deskew (de-skew), and forward error correction decoding, as shown in Table 1. Taking a 100G rate as an example, using 20 PCS lanes (physical coding sublayer channels), an alignment mark is inserted at an interval of 16384×66 on each channel, with an insertion interval of approximately 210 microseconds. Alignment mark loss determination requires four consecutive alignment mark cycles, at least 840 microseconds; locking determination requires two consecutive valid alignment marks, approximately 420 microseconds. If a forward error correction layer exists, an alignment mark locking operation is also required, requiring at least two alignment mark cycles, approximately 420 microseconds. Taking a 200G rate as an example, using eight physical coding sublayer channels, the alignment mark insertion interval is approximately 105 microseconds. Taking 400G as an example, using 16 physical coding sublayer channels, the alignment mark insertion period is 163840×257, and the insertion interval is approximately 105 microseconds. The OCS switching efficiency of optical circuit switching (OCS) = effective transmission time / (effective transmission time + link establishment and recovery time). The effective transmission time is the time used for actual transmission of service data after the port link establishment is completed within one time slot period. For optical circuit switching systems that require optical path reconfiguration at the millisecond level, the effective bandwidth is approximately 50% of the port bandwidth. Therefore, a typical high-speed port requires milliseconds for a single link re-establishment, becoming a key bottleneck restricting the realization of high-speed optical circuit switching.

[0016] Table 1. Link establishment time of physical coding sublayer at different rates

[0017] Currently, some related technologies exist to shorten link synchronization time or accelerate link recovery, but they all have shortcomings when applied to optical circuit switching scenarios. For example, in one related technology, after the second communication device receives data from the first communication device and determines that synchronization has failed, it sends a loss-of-lock indication to the fourth communication device; subsequently, after receiving the second data and determining that synchronization has been locked, it sends a lock indication, enabling the second host to quickly enter the synchronization process. This scheme also replaces part of the data in the second data with a first preset sequence, allowing the second host to synchronize based on the replaced preset sequence, thereby avoiding a long wait for the first host to complete synchronization with a large-interval insertion of alignment mark sub-sequences. Although this scheme shortens the synchronization detection waiting time, its implementation requires replacing part of the data with a preset sequence in the intermediate stage, which significantly modifies the processing flow of the 802.3 standard, resulting in compatibility issues and complex implementation. In optical circuit switching scenarios, after optical path switching, the port is first disconnected and then reconnected; this scheme does not address how to shorten the loss-of-lock determination time. Furthermore, this solution only applies to traditional port direct connection scenarios and does not consider the switching time of optical switching units in optical circuit switching or the switching coordination process between different ports, thus failing to comprehensively optimize the service recovery time during the optical circuit switching switching process.

[0018] Another related technology involves an optical transceiver system comprising a mode generator and a data selector. The data selector selects either a first bit stream data from a first network device or a second bit stream data from the mode generator based on reconfiguration conditions associated with the optical switch, and then transmits the selected data to the second network device. The data stream generated by the mode generator stores information such as clock phase and equalization parameters, enabling the physical medium connection sublayer to quickly complete clock locking after optical switch reconfiguration using these pre-stored parameters. This scheme accelerates the recovery process of the physical medium connection sublayer through pre-stored parameters; however, the entire link establishment process also includes a link establishment phase in the physical coding sublayer, which consumes most of the time. This scheme does not propose acceleration measures for the link establishment process in the physical coding sublayer. Furthermore, this scheme mainly involves processing on the receiving side, lacking consideration for cooperation between the transmitting and receiving sides to accelerate link establishment.

[0019] In view of this, and addressing the issue of long service link establishment and recovery times during OCS optical handover, this invention provides a method to accelerate service link establishment during OCS optical handover. The control plane is instantiated as a physical device, i.e., a controller. The OCS controller pre-notifies the associated source-end transmitting and sink-end receiving ports during OCS optical circuit handover, instructing them to enter a fast link establishment state. Insertion and detection are performed according to a pre-set AM period, which is much smaller than the standard AM interval, thereby significantly shortening the PCS layer link establishment time and increasing available bandwidth. An adaptive mechanism coordinates seamless switching between the transmitting and receiving sides in the fast link establishment state and normal operation state, improving OCS handover efficiency. Simultaneously, this invention is largely compatible with the 802.3 standard protocol.

[0020] After introducing the technical solution of this application, the various non-limiting embodiments of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. Please refer to [link to previous text] first. Figure 2 According to the method for accelerating the recovery of optical circuit-switched services provided in this application, it can be implemented as a computer program product, installed and run in an optical circuit-switched controller (OCS) to accelerate the recovery process of OCS services. In some embodiments of this method, the method can be executed by the OCS or by a functional module integrated into the OCS. The OCS is a device in an optical circuit-switched network used for optical path scheduling and switching control. It is connected to the optical switching unit and each service port through a control interface. The OCS can be a physical device independent of the ports and optical switching units, or it can be different functional components within the same device. The method includes the following steps: S201: When it is determined that there is a need for optical path switching, before switching the optical path connection, send a state switching command to the source port and the destination port corresponding to the physical layer optical link to be established, so that the source port transmitting side and the destination port receiving side enter the fast link establishment state.

[0021] Optical path switching requirement refers to the optical circuit switching controller determining, based on time slot scheduling plans or service transmission demands, the need to change the optical path connection relationship within the optical switching unit, switching the data transmission path from one optical path to another. Optical path switching requirements can be triggered by timed events, changes in service bandwidth requirements, or changes in port status. A physical layer optical link to be established refers to the need to switch the internal connection of the optical switching unit from the current pair of inlet and outlet optical paths to a new physical layer optical path between the target source port and the target destination port, based on the optical path switching requirement. The physical layer optical link includes the complete optical signal transmission path from the source port's optoelectronic converter, through the internal optical path of the optical switching unit, to the destination port's optoelectronic converter. The source port is the inlet port where data flows into the optical circuit switching network, and the destination port is the outlet port where data flows out of the optical circuit switching network. The source port transmitting side is the side of the source port used for transmitting data, and the destination port receiving side is the side of the destination port used for receiving data. The status switching command is the instruction information sent by the optical circuit switching controller to the source port and the destination port to instruct the ports to change their operating status. State switching commands can be sent via management messages or directly transmitted via electrical signals. The content of the state switching command includes information instructing the port to switch from normal operating state to fast link establishment state. Fast link establishment state is the operating state in which the port uses shorter alignment mark transmission and detection intervals during optical path switching to accelerate link establishment, which differs from the operating state the port is in during normal service transmission. Normal operating state refers to the state in which the port sends and receives alignment marks at standard intervals specified by the communication protocol and carries service data transmission.

[0022] In this step, when an optical path switching requirement exists, the optical circuit switching controller sends a state switching command to the source and destination ports corresponding to the physical layer optical link to be established before controlling the optical switching unit to perform the physical optical path switching. The state switching command can be a management message or an electrical signal. After receiving the command, the transmitting side of the source port and the receiving side of the destination port enter the fast link establishment state respectively.

[0023] S202: In the fast link establishment state, the source port transmitting side sends an alignment mark to the destination port receiving side according to the first transmission interval, and the destination port receiving side detects the alignment mark according to the first transmission interval.

[0024] The alignment mark is a special data block in the physical coding sublayer used for channel identification and providing forward error correction codeword boundaries. The first transmission interval is the time interval between transmitting and inserting the alignment mark in fast link establishment mode. The second transmission interval refers to the number of coding blocks or the time length between two adjacent insertions of the alignment mark on the transmitting side in normal operation mode, which is the standard alignment mark insertion interval specified by the communication protocol. The first transmission interval is less than the second transmission interval used by the destination port in normal operation mode.

[0025] In this step, after entering the fast link establishment state, the source port transmitter begins to continuously send alignment markers to the destination port receiver at a first transmission interval. The destination port receiver also uses this first transmission interval as a detection reference to detect the alignment markers. The value of the first transmission interval can be configured according to different port rates. At 100G rate, the first transmission interval can be set to the transmission time of sixteen codewords, approximately 0.8 microseconds; at 200G rate, the first transmission interval can be set to the transmission time of sixteen codewords, approximately 0.4 microseconds; at 400G rate, the first transmission interval can be set to the transmission time of thirty-two codewords, approximately 0.4 microseconds. Compared with the standard alignment marker interval, the standard interval at 100G is approximately 210 microseconds, and the standard interval at 200G and 400G rates is approximately 105 microseconds, indicating that the first transmission interval is significantly shorter than the second transmission interval.

[0026] S203: Control the optical switching unit to perform optical path switching operations to establish a physical layer optical link between the source port and the destination port.

[0027] The optical switching unit is a device that provides multi-path optical line switching functionality, offering multiple optical input / output interfaces to connect multiple incoming and outgoing service units. The optical circuit switching controller sends switching commands to the optical switching unit, controlling it to perform internal optical path switching operations, changing the physical optical path from its original connection to a new connection between the source and destination ports. The optical switching unit can be implemented as a microelectromechanical system (MEMS) optical switch, a planar waveguide optical switch, or a wavelength selective switch; none of these affect the implementation of this invention. For MEMS optical switching units, the typical switching time is several milliseconds; for planar waveguide optical switching units, the switching time can reach several microseconds; for wavelength selective switch optical switching units, the switching time is also in the range of microseconds to milliseconds. During the optical path switching operation, the source and destination ports are in an open-circuit state until the optical switching unit completes the switching.

[0028] S204: After the optical path switching operation is completed, the receiving side of the destination port detects the alignment mark from the transmitting side of the source port according to the first transmission interval, and determines that the link establishment is completed after detecting a preset number of valid alignment marks; after the link establishment is completed, the receiving side of the destination port and the transmitting side of the source port switch from the fast link establishment state to the normal operation state.

[0029] The normal working state is the regular working state in which the port sends and detects alignment marks according to the standard alignment mark interval after the link is established. The preset number refers to the number of valid alignment marks that the receiving side needs to continuously detect in order to determine that the alignment mark is locked.

[0030] In this step, after the optical path switching operation is completed and the optical signal is re-illuminating the photodetector at the destination port, the receiving side at the destination port first undergoes photoelectric conversion in the physical medium correlation sublayer and clock data recovery in the physical medium connection sublayer. Then, in the physical coding sublayer, it performs synchronization header detection, alignment mark detection, channel alignment, and forward error correction decoding. The alignment mark detection cycle is counted according to the first transmission interval. Because the first transmission interval is short, the alignment mark appears frequently in the data stream, and the receiving side at the destination port can continuously detect a preset number of valid alignment marks in a short time. When the number of detected valid alignment marks reaches the preset number (e.g., two valid alignment marks), after at least two consecutive detections of valid alignment marks, it enters a locked state. The locking time of the physical coding sublayer is significantly shortened. For example, at a 100G rate, the standard connection establishment time is approximately 1.26 milliseconds; with the first transmission interval, the theoretical connection establishment time can be shortened to the microsecond level. Figure 3 As shown. The receiving side of the destination port determines that the alignment mark is locked. After combining the channel de-skew and forward error correction codeword boundary locking, it confirms that the physical coding sublayer link establishment is complete. After the link establishment is completed, the receiving side of the destination port and the transmitting side of the source port switch from the fast link establishment state back to the normal working state. Subsequently, they send and receive alignment marks and perform service data transmission according to the second transmission interval.

[0031] In the technical solution provided in this application embodiment, before the optical path switching operation is executed, the source port transmitting side and the destination port receiving side pre-enter a fast link establishment state with a first transmission interval for transmitting and receiving alignment marks. Since the first transmission interval is less than the second transmission interval used in normal operation, the destination port receiving side detects the alignment marks according to the first transmission interval after the optical path switching is completed. This shortens the time required for the destination port receiving side to search for and align to the alignment marks after the optical path switching is completed. This allows the destination port receiving side to continuously detect a preset number of valid alignment marks in a shorter time, thereby reducing the waiting time between the completion of the optical path switching and the detection of a preset number of valid alignment marks by the destination port receiving side to determine the completion of the link establishment. This shortens the time occupied by the entire physical coding sublayer link establishment process, shortens the overall service recovery time during optical circuit switching, increases the effective time window available for transmitting service data per unit time in the optical circuit switching system, and improves the utilization rate of available bandwidth. Furthermore, by sending a status recovery notification to the optical circuit switching controller after the link establishment is completed, the optical circuit switching controller determines the service recovery time based on the link establishment success time and the start link establishment time, and determines the switching efficiency based on the service recovery time and the time slot duration. This allows for an accurate assessment of the actual time consumed by each optical path switching, thereby optimizing the optical path scheduling parameters and improving the available bandwidth utilization of the optical switching system.

[0032] Considering that during optical path switching, the receiving side of the destination port cannot detect the optical signal interruption in time and maintains the alignment mark locked state until multiple alignment mark detection cycles fail before determining that the lock has been lost, resulting in the lock loss process itself taking up extra time, based on this, the present invention also provides the following implementation method: During the optical path switching operation, the source port transmitting side continuously sends alignment markers; if the destination port receiving side detects optical signal loss or optical signal degradation during the optical path switching process, it resets the link establishment state to accelerate the entry into the unlocked state.

[0033] Among them, optical signal loss refers to the optical power detected by the receiver at the destination port being lower than a preset threshold, and optical signal degradation refers to the bit error rate of the received optical signal exceeding a preset threshold. Resetting the link establishment state means directly resetting the alignment mark locking state machine of the physical coding sublayer from the locked state or the partially locked state to the initial search state, without waiting for multiple alignment mark detection failures before determining loss of lock.

[0034] In this embodiment, during the optical path switching operation performed by the optical circuit switching unit, the source port transmitting side does not know when the physical switching of the optical path is completed, and therefore continues to transmit alignment marks according to the first transmission interval. During the optical path switching process, the destination port receiving side may detect optical signal loss or degradation due to the physical optical path being disconnected or switched. At this time, the destination port receiving side can transmit the detection result of optical signal loss or degradation to the physical coding sublayer, which then directly resets the locking state machine of the alignment mark and jumps to the initial search state. After the optical path switching is completed and the optical signal is restored, the destination port receiving side directly starts from the initial search state and detects alignment marks according to the first transmission interval. This avoids the process where the physical coding sublayer still counts multiple invalid alignment marks according to the periodicity of the first transmission interval before determining that the lock has been lost when the optical signal is interrupted, thereby further shortening the waiting time between the optical path switching and the start of re-searching for alignment marks.

[0035] As can be seen from the above, this embodiment actively resets the link establishment state when optical signal loss or degradation is detected, so that the receiving side of the destination port can immediately enter the initial search state, eliminating the waiting time consumed by the loss of lock determination, and can immediately start searching for alignment marks after the optical signal is restored, further shortening the overall service recovery time.

[0036] Based on the above embodiments, the present invention further defines the relationship between the second transmission interval and the first transmission interval, which may include the following: For example, the second transmission interval is an integer multiple of the first transmission interval. That is, the number of interval coding blocks between two adjacent alignment marks in normal operation is an integer multiple of the number of interval coding blocks between two adjacent alignment marks in fast link establishment mode. Taking a 100G port as an example, the second transmission interval specified by the 802.3 standard is to insert one alignment mark every 4096 forward error correction codewords. In fast link establishment mode, the first transmission interval can be configured to insert one alignment mark every 16 forward error correction codewords, in which case the second transmission interval is 256 times the first transmission interval. Taking a 200G port as an example, the standard second transmission interval is to insert one alignment mark every 4096 forward error correction codewords, and the first transmission interval can be configured to insert one alignment mark every 16 forward error correction codewords. Taking a 400G port as an example, the standard second transmission interval is to insert one alignment mark every 8192 forward error correction codewords, and the first transmission interval can be configured to insert one alignment mark every 32 forward error correction codewords.

[0037] If there is no integer multiple relationship between the first and second transmission intervals, the insertion position of the alignment mark will shift irregularly when the transmitting side switches from the fast link establishment state to the normal operation state, which may cause a temporary loss of lock on the receiving side. In this embodiment, the second transmission interval is set to be an integer multiple of the first transmission interval. This relationship allows the transmitting side to directly switch the transmission interval of the alignment mark from the first to the second transmission interval when switching from the fast link establishment state to the normal operation state. Since the second transmission interval is an integer multiple of the first transmission interval, the insertion position of the alignment mark after the switch still coincides with some alignment mark positions corresponding to the previous first transmission interval. During the transition period, the receiving side can simultaneously detect both intervals based on this integer multiple relationship, without losing the lock of the alignment mark due to the interval change.

[0038] As can be seen from the above, this embodiment guarantees the integer multiple relationship between the two intervals, making the phase relationship of the alignment mark predictable when the transmission interval is switched, and the receiving side can smoothly follow the interval change without losing the lock, thus achieving a seamless transition of the link establishment state.

[0039] Furthermore, considering that the value of the first transmission interval needs to ensure that the insertion of the alignment mark does not destroy the structural integrity of the forward error correction codeword, and that the complete alignment mark code group can be accommodated on each parallel coding channel, this embodiment also limits the first transmission interval to be configured based on the duration of a single forward error correction codeword as the basic unit, and based on the product of the number of forward error correction coding channels, the alternation period of odd and even codewords, and the adjustable positive integer coefficient.

[0040] The forward error correction codeword duration refers to the time required to transmit a complete forward error correction codeword. A forward error correction codeword contains the original data information and parity redundancy information. For RS-FEC (544,514) encoding, a codeword contains 5140 bits of original data and 300 bits of parity redundancy, totaling 5440 bits. The number of forward error correction coding channels refers to the number of parallel coding channels to which the physical coding sublayer distributes the data. The parity codeword alternation period reflects the arrangement of parity codewords; a value of 2 indicates that an alignment mark consists of two consecutive coding blocks. The adjustable positive integer coefficient is a variable parameter used to adjust the size of the first transmission interval.

[0041] In this embodiment, the first transmission interval is based on the duration of a single forward error correction codeword, and is equal to the product of the number of forward error correction coding channels, the parity codeword alternation period, and the adjustable positive integer coefficient. For example, if the number of forward error correction coding channels is M, the parity codeword alternation period is 2, and the adjustable positive integer coefficient is N, then the first transmission interval is equal to M multiplied by 2 multiplied by N codewords. Taking a 100G rate port as an example, the number of forward error correction coding channels is 4, the parity codeword alternation period is 2, and if N is chosen to be equal to 2, then the first transmission interval is equal to 4 × 2 × 2, that is, 16 forward error correction codewords. Taking a 400G rate port as an example, the number of forward error correction coding channels is 16, the parity codeword alternation period is 2, and if N is chosen to be equal to 1, then the first transmission interval is equal to 16 multiplied by 2 multiplied by 1, that is, 32 forward error correction codewords.

[0042] As can be seen from the above, the first transmission interval is set to an integer multiple of the product of the number of forward error correction coding channels and the alternation period of odd and even codewords. This ensures that alignment marks can be inserted at the same position on each coding channel, and that the alignment marks do not cross the codeword boundary, thus guaranteeing the standardization of the physical coding sublayer coding format in the fast link establishment state.

[0043] Considering that in a bidirectional optical link, the source port transmitting side cannot directly know the link establishment status of the destination port receiving side, if the source port transmitting side starts sending service data before the destination port receiving side has completed link establishment, data loss will occur. Based on this, the present invention solves this problem through the following implementation method, which may include the following: The process of the receiving side of the destination port and the sending side of the source port switching from the fast link establishment state to the normal working state includes: the receiving side of the destination port, after confirming that the link establishment is completed, sends a link establishment indication message to the receiving side of the source port through the sending side of the destination port, and switches from the fast link establishment state to the normal working state; the sending side of the source port receives the link establishment indication message and switches from the fast link establishment state to the normal working state.

[0044] The established link indication information is a notification signal sent from the destination port receiver to the source port receiver via the destination port transmitter after confirming that the physical coding sublayer link has been established. This information can be carried in a specific code group of the physical coding sublayer or represented by control code blocks transmitted on the optical link.

[0045] In this embodiment, after the receiving side of the destination port detects a preset number of valid alignment markers according to the first transmission interval, it completes alignment marker locking, channel deskewing, and forward error correction codeword boundary locking, confirming that the physical coding sublayer link establishment is complete. At this time, the receiving side of the destination port notifies the transmitting side of the destination port of the link establishment completion status. The transmitting side of the destination port uses this status as a link establishment indication information and sends it to the receiving side of the source port through the established optical link. After sending the link establishment indication information, the receiving side of the destination port switches from the fast link establishment state to the normal working state. After completing its own physical coding sublayer link establishment, the receiving side of the source port can correctly parse the data stream from the transmitting side of the destination port and extract the link establishment indication information from it. The receiving side of the source port transmits this information to the transmitting side of the source port, and the transmitting side of the source port knows that the receiving side of the destination port has completed the link establishment, and then switches from the fast link establishment state to the normal working state.

[0046] In one implementation, the established link indication information can be carried using the local fault and remote fault mechanisms defined in the 802.3 standard. While the receiving side of the destination port has not completed link establishment, the sending side of the destination port continuously sends a remote fault code stream to the source port. Once the receiving side of the destination port completes link establishment, the sending side of the destination port stops sending the remote fault code stream and switches to sending a normal idle code stream. The receiving side of the source port determines that the destination port has completed link establishment once it detects that the code stream has changed from remote fault to normal idle.

[0047] As can be seen from the above, in this embodiment, the destination port sends a link establishment indication information to the source port through the reverse link, so that the sending side of the source port can accurately know the time point when the link establishment of the other end is completed. Only after this does it switch to normal working state and start transmitting service data, ensuring that the receiving side of the destination port is in a normal receiving state when the service data is sent.

[0048] Furthermore, considering that the switching timing of the source port transmitting side and the destination port receiving side is not completely synchronized, during the switching process, there may be a situation where one side has already transmitted according to the new interval while the other side is still detecting according to the old interval, resulting in the loss of alignment mark lock. Based on this, the present invention solves this problem through the following implementation method, which may include the following: Before the receiving side of the destination port switches from the fast link establishment state to the normal operation state, it first enters the transition state. In the transition state, the sending side of the source port sends an alignment mark at a first transmission interval or a second transmission interval, and the receiving side of the destination port simultaneously detects the alignment mark at the first transmission interval and the second transmission interval. After detecting the alignment mark sent according to the second transmission interval, the receiving side of the destination port switches from the transition state to the normal operation state.

[0049] The transition state is an intermediate working state between the fast link establishment state and the normal working state. In the transition state, the alignment mark detection logic on the receiving side of the destination port is compatible with both the first transmission interval and the second transmission interval, and can correctly identify the alignment mark transmitted in either interval and maintain the locked state of the alignment mark.

[0050] In the specific implementation, after establishing a link, the receiving side of the destination port does not immediately switch to the normal working state where alignment markers are detected only at the second transmission interval. Instead, it enters a transition state. Upon receiving the established link indication, the transmitting side of the source port may switch its transmission interval from the first to the second transmission interval at a certain alignment marker insertion boundary. Before the switch, the source port transmitting side still transmits alignment markers at the first transmission interval; after the switch, it transmits alignment markers at the second transmission interval. During the transition state, the receiving side of the destination port maintains two sets of alignment marker detection counters. One set detects according to the period of the first transmission interval, and the other according to the period of the second transmission interval. As long as one set of counters detects a valid alignment marker, the receiving side of the destination port maintains the alignment marker locked state. When the receiving side of the destination port detects a valid alignment marker transmitted according to the second transmission interval for the first time, it confirms that the transmitting side of the source port has completed the transmission interval switch. At this point, the receiving side of the destination port exits the transition state and officially enters the normal working state, subsequently detecting alignment markers only according to the second transmission interval.

[0051] As can be seen from the above, this embodiment introduces a transition state so that the receiving side of the destination port can simultaneously accommodate the detection of two intervals during the handover. It only completes the final handover after confirming that the other end has completed the interval handover, thereby ensuring a smooth transition from the fast link establishment state to the normal working state and avoiding the link being disconnected again due to the asynchronous interval handover.

[0052] Considering that if the optical circuit switching controller lacks accurate link establishment time data when scheduling time slots, it cannot perform differentiated scheduling based on the actual link establishment time of different optical path combinations, resulting in low overall bandwidth utilization efficiency, this embodiment also provides the following implementation method, which may include the following: When a status recovery notification is received from the source port transmitting side or the destination port receiving side after switching to normal working state, the link establishment success time is determined based on the status recovery notification; the service recovery time is determined based on the link establishment success time and the start link establishment time; the switching efficiency is determined based on the service recovery time and the time slot duration, and the optical path scheduling parameters are optimized based on the switching efficiency.

[0053] The "State Recovery Notification" refers to a notification signal sent by the source port transmitting side or the destination port receiving side to the optical circuit switching controller after successfully switching to normal operating status. This notification signal can be a management message or an electrical signal, used to inform the optical circuit switching controller that the link establishment process has been completed. The "Link Establishment Success Time" is the moment the optical circuit switching controller receives the "State Recovery Notification." The "Link Establishment Start Time" is the moment the optical circuit switching controller sends state switching commands to the source and destination ports. The "Service Recovery Time" is the length of time between the "Link Establishment Start Time" and the "Link Establishment Success Time." "Switching Efficiency" refers to the proportion of effective transmission time to the total time slot duration within a time slot period. "Optical Path Scheduling Parameters" are the parameters used by the optical circuit switching controller when allocating time slots and planning optical paths, including the time slot duration allocation for each optical path and the switching order between optical paths.

[0054] In this embodiment, when the receiving side of the destination port and the transmitting side of the source port switch from the fast link establishment state to the normal operation state, the destination port or the source port sends a status recovery notification to the optical circuit switching controller. Upon receiving the status recovery notification, the optical circuit switching controller records the moment of receipt as the link establishment success time. The optical circuit switching controller compares this link establishment success time with the previously recorded start link establishment time of this optical path switch; the difference between the two is the service recovery time of this optical path switch. The optical circuit switching controller updates the service recovery time to the record corresponding to this optical path in the link establishment time table. The optical circuit switching controller calculates the switching efficiency of this switch based on the service recovery time and the time slot duration allocated for this optical path connection. The switching efficiency can be obtained by subtracting the service recovery time from the time slot duration and then dividing by the time slot duration. The optical circuit switching controller adjusts the allocation of subsequent time slots based on the switching efficiency data accumulated from multiple optical path switches. For example, for optical path combinations with long service recovery times, the optical circuit switching controller can allocate longer time slot durations to reduce switching frequency; for optical path combinations with short service recovery times, the optical circuit switching controller can allocate shorter time slot durations to improve the flexibility of optical path utilization.

[0055] As can be seen from the above, this embodiment can obtain the accurate link establishment success time for each switch through the optical circuit switching controller, calculate the accurate switching efficiency, and dynamically adjust the subsequent optical path scheduling parameters accordingly, so that the time slot allocation matches the actual link establishment time of each optical path, thereby improving the overall bandwidth utilization efficiency of the optical circuit switching system.

[0056] Considering that the transmission paths and response delays of the commands sent by the optical circuit switching controller to each port and optical switching unit may differ, resulting in a misalignment between the time when the port enters the fast link establishment state and the time when the optical switching unit completes the optical path switching, this invention also provides the following implementation, which may include the following: Send a state switching command carrying time information to the source port and the destination port. When the timer reaches the time indicated by the time information, the sending side of the source port and the receiving side of the destination port enter the fast link establishment state.

[0057] The time information refers to a time value carried in the state transition instruction, which specifies the exact moment when the source port and destination port perform the state transition. The timer is an internal timing module within the port, used to track the current time and compare it with the time information.

[0058] In one implementation, when the optical circuit switching controller sends a state switching command to the source and destination ports, it includes time information in the command. This time information indicates a future moment that is coordinated with the expected completion time of the optical switching unit's switchover. Upon receiving the state switching command with the time information, the source and destination ports do not immediately enter the fast link establishment state. Instead, they start or check their respective timers. When the current moment indicated by the timer reaches the moment indicated by the time information, the source port transmitting side and the destination port receiving side simultaneously enter the fast link establishment state. This method allows the optical circuit switching controller to send the state switching command to each port in advance, without waiting for the optical switching unit to be ready. The unified state switching of each port at the specified time precisely coordinates with the optical path switching action of the optical switching unit, avoiding mismatches between the link establishment state and the optical path state caused by command transmission delays or inconsistent response times of different modules.

[0059] As can be seen from the above, this embodiment carries time information in the state switching command. Each port enters the fast link establishment state synchronously at a preset time according to the same time base, which ensures the timing coordination between port state switching and optical path switching and avoids invalid transmission or invalid waiting of alignment marks caused by entering the fast link establishment state in advance or in a late manner.

[0060] If the optical circuit switching controller does not pre-assess the link establishment time during time slot allocation, it may result in an allocated time slot being too short to complete link establishment, or an allocated time slot being too long, wasting bandwidth resources. Based on this, the present invention also provides the following implementation method, which may include the following: Obtain the estimated establishment time of the physical layer optical link to be established: If the physical layer optical link to be established is being established for the first time, the initial establishment time corresponding to the physical layer optical link to be established is read from the initial reference data, and the initial establishment time is used as the estimated establishment time of the physical layer optical link to be established; the initial reference data is generated during initialization by traversing and configuring each physical layer optical link and based on the initial establishment time of each physical layer optical link obtained through training; if the physical layer optical link to be established is not being established for the first time, the historical establishment data of the physical layer optical link to be established within the historical time period is read from the establishment time table, and the establishment time of the physical layer optical link to be established is determined based on the historical establishment data. The estimated link establishment time is recorded in the link establishment timetable, which records the actual historical link establishment completion time and corresponding start time of each physical layer optical link. Based on the bandwidth requirements, port rate, and estimated link establishment time of the service to be transmitted, the new time slot duration allocated to the physical layer optical link to be established is determined. Based on the new time slot duration, port rate, and estimated switching efficiency determined by the estimated link establishment time, the estimated total amount of data to be transmitted within the new time slot duration is calculated, and the new time slot duration is determined to be valid when the estimated total amount of data to be transmitted meets the bandwidth requirements. When the time slot corresponding to the new time slot duration begins, a state switching command is sent to the source port and destination port corresponding to the physical layer optical link to be established.

[0061] The estimated link establishment time refers to the preliminary estimate made by the optical circuit switching controller (OCS) based on historical data before performing the optical path handover, regarding the service recovery time required for this handover. Initial reference data is a set of data generated during the system initialization phase, recording the link establishment time spent on each physical layer optical link during its initial establishment. The link establishment timetable is a data table maintained by the OCS, recording the actual link establishment time of each physical layer optical link during each handover process. The new timeslot duration refers to the length of the timeslot allocated by the OCS for this optical path connection. The estimated total data transmission volume refers to the amount of data that can be transmitted within the new timeslot duration, after deducting the estimated link establishment time, and is calculated jointly by the new timeslot duration, port rate, and estimated link establishment time.

[0062] After determining that an optical path switching requirement exists, the optical circuit switching controller first obtains the estimated establishment time of the physical layer optical link to be established. If the optical link is being established for the first time, i.e., no optical path switching from the source port to the destination port has been performed before, the initial establishment time corresponding to the optical link is read from the initial reference data and directly used as the estimated establishment time. The initial reference data is generated as follows: during the system power-on initialization phase, the optical circuit switching controller traverses and configures all optical paths, establishing optical path connections between each source port and each destination port one by one, recording the initial establishment time of each optical path, integrating these time data into the initial reference data, and storing it. If the optical link is not being established for the first time, the optical circuit switching controller reads multiple historical establishment data of the optical link within a historical time period from the establishment time table. Each record in the establishment time table contains the actual completion time of the establishment of a certain optical link in a certain switch and the start time of the establishment of the connection in that switch; the difference between the two is the actual establishment time of that switch. The controller can take the average of multiple historical chain establishment times, or take the maximum value plus a protection margin, as the estimated chain establishment time for this switchover.

[0063] After obtaining the estimated link establishment time, the optical circuit switching controller (OCS) determines the new time slot duration allocated to the new optical path connection based on the bandwidth requirements of the service to be transmitted, the port rate, and the estimated link establishment time. For example, the determination method may include: first calculating the basic transmission time based on the data volume of the service to be transmitted and the port rate; then adding a protection margin to the larger of the basic transmission time and the estimated link establishment time as the new time slot duration. After the new time slot duration is determined, the OCS calculates the estimated total data volume to be transmitted within the new time slot duration based on the new time slot duration, the port rate, and the estimated switching efficiency determined by the estimated link establishment time. The estimated switching efficiency is equal to the difference between the new time slot duration and the estimated link establishment time, divided by the new time slot duration. The estimated total data volume to be transmitted is equal to the port rate multiplied by the new time slot duration and then multiplied by the estimated switching efficiency. When the estimated total data volume to be transmitted is greater than or equal to the data volume of the service to be transmitted, the new time slot duration is deemed valid. When the time slot corresponding to the new time slot duration arrives, the optical circuit switching controller sends a state switching command to the source port and destination port corresponding to the physical layer optical link to be established at the start of the time slot, thus initiating the optical path switching and fast link establishment process.

[0064] As can be seen from the above, the optical circuit switching controller in this embodiment uses historical link establishment data to estimate the link establishment time of this switch before each switch, and calculates a reasonable time slot length accordingly, ensuring that the time slot length can cover the link establishment time and meet the service bandwidth requirements, thereby improving the utilization efficiency of bandwidth resources while avoiding link establishment failure.

[0065] Based on the above embodiments, this embodiment also provides an exemplary implementation of the technical solution of the present invention, such as... Figure 4As shown, in this embodiment, the OCS control plane is instantiated as an OCS controller. The interaction process between the OCS controller and the source port, destination port, and optical switching unit is as follows: A1: The OCS controller allocates the OCS optical switching path and time slot duration in real time.

[0066] In one possible implementation, the OCS controller traverses and configures all OCS paths during initialization, trains to obtain the initial link establishment time of each path, and stores it in the corresponding table entry as initial reference data for OCS switching efficiency; in another possible implementation, the OCS controller comprehensively derives the optical switching path and the time slot duration of the path based on information such as service bandwidth requirements, port rates, and switching efficiency.

[0067] A2: The OCS controller notifies both the sending and receiving sides of the link to switch to fast link establishment mode.

[0068] In one possible implementation, the OCS controller and the two side ports are independent devices, and the handover request can be notified to the two side ports of the link via messages. In another possible implementation, the OCS controller and the two side ports are different components in the same device, and can be notified via signal connections. In one possible implementation, after the OCS controller issues a handover instruction, the two side ports immediately switch to fast link establishment state. In another possible implementation, the handover instruction issued by the OCS controller carries time information, and the two side ports switch to fast link establishment state when the timer expires. In one possible implementation, the port shortens the AM transmission and detection cycle of the PCS layer, and may also include the FEC sublayer, in fast link establishment state. When the transmitting side is in fast link establishment state, it continuously notifies the PCS layer to insert the identifier-aligned AM code interval according to the preset first transmission interval, and notifies the other end of the status of the receiving side. When the receiving side is in fast link establishment state, it continuously notifies the PCS layer to perform identifier-aligned AM code detection using the first transmission interval.

[0069] A3: The OCS controller notifies the OCS of the optical switching unit switching, the OCS rebuilds the physical layer optical link, and the receiving side accelerates the link down (link disconnection).

[0070] In one possible implementation, the OCS controller and the OCS optical switching unit are independent devices, and the switching request can be notified to the OCS optical switching unit via messages. In another possible implementation, the OCS controller and the OCS optical switching unit are different components in the same device, and can be notified via internal signal connections. OCS optical link reconstruction takes a certain amount of time. In one possible implementation, the PCS layer state machine can be quickly notified of information such as OCS optical signal loss, degradation, and physical layer PMA clock lock-out. In another possible implementation, the OCS optical link reconstruction time is extremely short, and the PCS layer synchronization header detection has not reached the lock-out condition. The receiving PCS layer cannot receive a valid identifier-aligned AM code within a preset time interval. Since the first transmission interval is much smaller than the standard time interval, the PCS layer AM will quickly lose lock-out. A4: The optical switching unit of the OCS completes the establishment of the optical link, and the destination port receives the data stream carrying fast link establishment information, thus accelerating the link establishment.

[0071] In one possible implementation, during the OCS optical path reconstruction process, the link source port can continuously send fast AM information. Once the OCS completes the optical link establishment, the receiving side of the destination port first goes through the PMA layer clock and data recovery, serial-to-parallel conversion, etc., and then performs synchronization header detection, AM detection, channel alignment, FEC decoding, etc. at the PCS layer. The AM detection period is counted according to a preset value. Since the preset period is less than the standard time interval, the PCS layer accelerates the locking.

[0072] A5: After the destination port successfully establishes a link, it sends a link establishment indication message to the source port via OCS and automatically switches to normal working status.

[0073] In one possible implementation, after successful link establishment at the PCS layer of the receiving port, the system automatically enters normal operation and sends a local lock information message to the source port via the OCS. This message can be correctly identified after successful link establishment at the receiving PCS layer of the source port. In another possible implementation, a transitional state can be performed before entering normal operation. Since it is uncertain whether the receiving side of the destination port or the transmitting side of the source port will establish the link first, in the transitional state, the transmitting side may transmit according to a preset value or a standard AM value. The receiving side can be compatible with both preset and standard AM values, and the two values ​​satisfy an integer multiple relationship. Therefore, as long as either one is satisfied, the link establishment can remain normal. Starting from a certain AM boundary, the AM interval of the transmitting side changes from the preset value to the standard interval. After detecting the first standard interval, the receiving side enters normal operation and performs detection according to the standard AM value, thus achieving a seamless switch from rapid link establishment to normal operation. In one possible implementation, after successful link establishment at the receiving port, the OCS controller can be notified immediately via a message or signal connection so that the OCS controller can obtain the time of successful link establishment at the receiving side.

[0074] A6: After the source port receives the successful connection establishment indication from the destination port, it also switches to normal working state and allows sending services until the end of this time slot.

[0075] In one possible implementation, after the source port switches to normal operating state, it also includes notifying the PCS layer to switch to standard AM interval insertion from the next AM cycle and allowing the transmission of service data; selecting different data and AM to be transmitted in different states through a selector; in another possible implementation, after the source port switches to normal operating state, it also includes immediately notifying the OCS controller via a message or signal connection so that the OCS controller can obtain the time when the link was successfully established on the transmitting side.

[0076] A7: The OCS controller calculates the switching efficiency based on the connection establishment time and optimizes the relevant parameters of the scheduling algorithm.

[0077] In one possible implementation, the OCS controller calculates the exact time consumed by the entire link establishment process based on the successful link establishment time on the transmitting or receiving side and the start time of OCS handover. For example, the handover efficiency can be further calculated using the relational formula: handover efficiency = 1 - (link establishment completion time - link establishment start time) / time slot duration. Then, the maximum bandwidth throughput = port rate can be used to calculate the handover efficiency. Time slot duration The switching efficiency is then used to determine the maximum bandwidth throughput of the optical switch. In one possible implementation, the OCS controller can also maintain link establishment time entries between each path in the OCS; and evaluate the average optical line switching efficiency and bandwidth based on data from multiple training iterations, and further optimize the scheduling algorithm.

[0078] As can be seen from the above, this embodiment accelerates port link establishment by having the OCS controller notify the associated source and destination ports to enter a fast link establishment state in advance during OCS optical circuit switching, which can significantly shorten the service recovery time in OCS switching scenarios. By returning the precise time of each link establishment completion to the OCS controller, it can accurately evaluate the OCS switching efficiency, optimize the OCS scheduling algorithm, and improve the utilization rate of OCS switching bandwidth. This relatively simple method of accelerating PCS link establishment can achieve adaptive switching in physical layer working mode without defining special AM and additional mechanisms, and has strong standard protocol compatibility.

[0079] It should be noted that there is no strict order of execution for the steps in this application. As long as they conform to a logical order, these steps can be executed simultaneously or in a certain preset order. Figure 2 This is just an illustrative example and does not mean that this is the only possible execution order.

[0080] Furthermore, this application also provides an apparatus for accelerating the recovery of optical circuit-switched services; please refer to [link to relevant documentation]. Figure 5 The system may include an inbound service terminal 51, an optical circuit switching controller 52, an optical circuit switching unit 53, and an outbound service terminal 54. The link establishment accelerator of the inbound service terminal 51 is connected to the optical circuit switching controller 52, and is used to receive state switching instructions and return the link establishment completion time. The physical medium connection sublayer or physical medium related sublayer of the inbound service terminal is connected to the optical circuit switching unit via an optoelectronic converter. The optical circuit switching unit 53 is connected to the optical circuit switching controller 52, and is used to perform optical path switching operations after receiving a state switching instruction. The link establishment accelerator of the outbound service terminal 54 is connected to the optical circuit switching controller 52, and is used to receive state switching instructions and return the link establishment completion time. The physical medium connection sublayer or physical medium related sublayer of the outbound service terminal is connected to the optical circuit switching unit via an optoelectronic converter. The optical circuit switching controller 52 is used to execute a computer program to implement the steps of the method for accelerating optical circuit switching service recovery as described in any of the above embodiments.

[0081] Among them, the inbound service terminal 51 is a port device located on the ingress side in the optical circuit switching network, such as... Figure 5As shown, there can be multiple of these modules, used to convert the data to be exchanged from electrical signals to optical signals and send them to the optical switching unit. The incoming service end internally includes a service transmission processing module, a media access control layer and coordination sublayer transmission processing module, a link establishment accelerator, a selector, a physical coding sublayer transmission processing module, a physical media connection sublayer and physical media related sublayer transmission processing module, and an electro-optical converter. The link establishment accelerator is a functional module in the incoming service end 51 used to manage the switching between the fast link establishment state and the normal operation state. Internally, it runs a state machine, determining the current state based on information such as whether OCS switching is required, whether the local end is locked, and whether the peer end is locked. Based on the current state, it transmits information carrying the standard AM or fast link establishment AM cycle flag to the PCS transmission side and notifies the peer end of whether the local end is locked. Simultaneously, if link establishment is complete, it immediately notifies the OCS controller of the completion flag. The transmission of the PCS and FEC sublayers is processed according to the corresponding protocol based on the AM cycle value, and after PMA and PMD transmission processing and electro-optical conversion, it is connected to the OCS optical switching unit. The selector chooses to import data streams from the link building accelerator or from the media access control layer and coordination sublayer, depending on the current operating status.

[0082] The optical circuit switching controller 52 is a control device for optical path scheduling and switching management, providing bidirectional interfaces connected to the optical circuit switching unit 53, multiple inbound service terminals 51, and multiple outbound service terminals 54. The steps of the method for accelerating optical circuit switching service recovery executed by the optical circuit switching controller 52 may include or be divided into one or more program modules. These program modules are stored in a storage medium and executed by the OCS controller to complete the corresponding steps of the method for accelerating optical circuit switching service recovery disclosed in this embodiment. In this embodiment, a program module refers to a series of computer program instruction segments capable of performing a specific function. The optical circuit switching unit 53 is a device for connecting multiple optical signals, providing multiple optical input interfaces and optical output interfaces, respectively connected to the optoelectronic converters at the inbound and outbound service terminals. The optical circuit switching unit has a control interface connected to the optical circuit switching controller, receiving switching commands issued by the optical circuit switching controller and performing internal optical path switching.

[0083] The outgoing service end 54 is a port device located on the egress side of the optical circuit-switched network. Multiple devices can exist within this end, used to receive optical signals from the optical switching unit and convert them into electrical signals for data reception and processing. Internally, the outgoing service end includes an opto-to-electrical converter, a physical media correlation sublayer and physical media connection sublayer receiving and processing module, a physical coding sublayer receiving and processing module, a link establishment accelerator, a media access control layer and coordination sublayer receiving and processing module, and a service reception and processing module. After opto-to-electrical conversion, the light output from the OCS optical switching unit enters the PMD and PMA receiving and processing of the outgoing service end 54. Then, the PCS and FEC receiving sides perform corresponding protocol processing based on the current AM cycle value. The link establishment accelerator on the outgoing service end also runs a state machine, which determines whether the current state is fast link establishment or normal operation based on information such as whether OCS fast handover is required and whether the local end is locked. Based on the current state, it determines whether the PCS and FEC receiving sides use the standard AM or fast link establishment AM cycle. By introducing fast link establishment AM cycle detection during OCS handover, the unlocking and locking processes on the PCS receiving side can be accelerated, thereby shortening the overall service establishment time.

[0084] As can be seen from the above, this embodiment sets up link establishment accelerators in the inbound and outbound service ends and establishes a control path with the optical circuit switching controller, so that the controller can coordinate the action timing of each port and optical switching unit, pre-configure the port alignment mark transmission and reception parameters before optical path switching, and collect link establishment time data after switching is completed and feed it back to the scheduling process, thereby realizing the function of accelerating the recovery of optical circuit switching services at the device level.

[0085] Finally, in an OCS optical circuit switching network, optical circuit management is typically performed using time-slot scheduling by the OCS controller. Connections between different optical ports are switched in a time-division manner. To make the technical solution of this invention clearer to those skilled in the art, this embodiment uses the example of switching from OCS inbound port 1 to outbound port 2 and then to inbound port 3 to outbound port 2, which may include the following: When the system is powered on and initialized, the OCS controller traverses and configures all OCS paths, trains and obtains the initial link establishment time of each path, and stores it in the corresponding table entry as the initial reference data for OCS switching efficiency.

[0086] During normal operation, the OCS controller determines the bandwidth requirement for the next time slot, based on information such as service bandwidth demand, port rate, and switching efficiency, to switch from connecting inbound port 1 to outbound port 2 to connecting inbound port 3 to outbound port 2, and calculates the duration of the time slot. For example, the duration of the time slot = max(service data volume / port rate, estimated link establishment time) + protection margin). The estimated link establishment time is obtained by querying initial reference data or a link establishment schedule established during operation. For the link establishment schedule, the average (or maximum) time historically recorded for this path can be used as the estimated link establishment time. The link establishment schedule records the completion time and start time of each optical link establishment. The start time is the moment the state switching command is issued. The switching efficiency = 1 - (completion time - start time) / time slot duration is used to calculate the total time consumed in the link establishment process. The link establishment schedule can also store the calculated switching efficiency for later querying. The maximum amount of data switched in a time slot is determined by the time slot duration, switching efficiency, and port rate: Maximum amount of data switched = Port rate Time slot duration Switching efficiency.

[0087] At the start of the next time slot, the OCS controller notifies the transmitting side of port 3 and the receiving side of port 2 to switch to fast link establishment mode, and notifies the OCS to perform optical line reconstruction, as follows: Figure 7 As shown. The detailed procedures for the transmitting side (port 3) and the receiving side (port 2) during this process are as follows: Figure 8 As shown, the state timing diagram of each stage during the entire implementation process is as follows: Figure 9 As shown.

[0088] On the port 3 transmitting side: After receiving the switching command from the OCS controller, the state machine enters the fast link establishment state. In this state, it continuously notifies the PCS layer to insert AM code intervals according to the preset fast identifier alignment. The preset AM code interval is also the first transmission interval in the above embodiment, and the 802.3 standard AM interval is the second transmission interval in the above embodiment. For example, the standard AM interval is an integer multiple of the preset AM code interval, and the preset value is usually shorter. The state of the local receiving side is then notified to the peer side through the OCS path. In some embodiments, the peer side can be notified through the Local Fault and Remote Fault mechanisms in 802.3. For example, when the local end loses lock, a Remote Fault data stream is continuously sent; after the local end has locked, a normal IDLE or data stream is sent. In the 802.3 standard, the role of AM is channel identification and to provide boundary references for FEC and PCS. The standard AM interval T inserts a group every 4096 codewords for 100G / 200G and every 8192 codewords for 400G. Each codeword in RS-FEC(544, 514) is 5440 bits, containing 5140 bits of original information and 300 bits of redundant information, such as... Figure 10 As shown. In this embodiment, the fast AM interval T1 can be the number of FEC lanes. 2 Integer multiples of codewords, i.e., T1=N 4 2 codewords. Furthermore, it satisfies that the fast AM interval T1 is a divisor of the standard AM period T; that is, T1 M=T ensures that even if the receiving side uses T as the AM detection cycle and the transmitting side uses T1 as the AM transmission cycle, the receiving side can still maintain a locked state and seamlessly transition from fast AM to standard AM intervals. When port 3 receives the link establishment success flag from port 2, it indicates that the link from port 3 to port 2 via the OCS optical switch is normal. The transmitting side of port 3 can switch to normal operation, switch to standard AM interval insertion from the next AM cycle, and allow services to be transmitted through port 3. At the same time, the switching time information is notified to the OCS controller, which reflects the actual start time of service transmission.

[0089] OCS Optical Circuit Switching: After receiving the switching command from the OCS controller, the optical circuit switching begins. The switching time varies depending on the different technical implementation methods. For example, for MEMS (Micro-Electro-Mechanical Systems) OCS, the typical switching time is several milliseconds, while for silicon waveguide OCS, the switching time can reach several microseconds. During this process, port 3 and port 2 are disconnected until the OCS completes the switching. On the receiving side of Port 2: After receiving the switching command from the OCS controller, the state machine enters the fast link establishment state. In this state, it continuously notifies the PCS layer to align the AM code interval detection according to the preset fast identifier. The preset AM code interval is consistent with that negotiated with the transmitting side. During the OCS switching process, the receiving side of Port 2 will detect optical signal loss or degradation, which may lead to the loss of lock in the PMA layer clock phase-locked loop. In some embodiments, the PCS layer can directly reset the PCS layer state machine to the initial state based on the above information to accelerate the AM loss. In other embodiments, the PCS layer may use a local clock or continue to run the protocol state machine. When the preset fast AM code interval counter expires, it must detect invalid AM at least four times before entering the loss state and re-sliding the AM window. After the OCS handover is completed, the optical signal recovers and stabilizes. The receiving side at port 2 first undergoes clock and data recovery at the PMA layer, serial-to-parallel conversion, etc., followed by synchronization header detection, AM detection, channel alignment, and FEC decoding at the PCS layer. The AM detection cycle is counted according to a preset value; at least two consecutive valid AM detections are required to enter a locked state. Because the preset AM cycle is much shorter than the standard time interval, the PCS layer locking time is significantly shortened. After successful link establishment at the PCS layer on the receiving side of port 2, a locked information message can be sent to source port 3 via the OCS. This message can be correctly recognized and used to initiate a state machine transition on the transmitting side after successful link establishment at the receiving PCS layer of source port 3.

[0090] In this embodiment, before the receiving side of port 2 enters the normal operating state, it can first go through a transition state. The source port 3 may switch from the preset AM period to the standard AM period at some point. During the transition state of the receiving side of port 2, it can simultaneously perform detection according to the preset value and the standard AM value. The two satisfy an integer multiple relationship, so as long as one condition is met, the link establishment can be maintained normally. Starting from a certain AM, after the receiving side detects the first standard interval, it enters the normal operating state and performs detection according to the standard AM value, thereby realizing a seamless switch from fast link establishment to the normal operating state.

[0091] In this embodiment, for 100G, fast AM can be inserted once every 16 codewords, with a time interval of approximately 0.8µs. During fast link establishment, the receiver detects at 16 codewords. After locking, in the transition state, it detects simultaneously at both 16 and 4096 codeword intervals. At this time, the transmitter may still transmit at 16 codewords. After a certain point, the transmitter switches to the standard 4096 codeword transmission interval. After detecting the standard AM interval in the transition state, it enters the working state and detects at the standard AM interval, such as... Figure 11 As shown.

[0092] Furthermore, this application also provides an electronic device, described from a hardware perspective. The electronic device includes a memory and an OCS controller. The memory stores a computer program, and the OCS controller is configured to run the computer program to perform the relevant steps executed by the OCS controller in any of the above-described embodiments of the method for accelerating the recovery of optical circuit-switched services.

[0093] It is understood that if the method for accelerating optical circuit-switched service recovery in the above embodiments is implemented as a software functional unit and sold or used as an independent product, it can be stored in a non-volatile storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the related technology, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and executes all or part of the steps of the methods in the various embodiments of this application. The aforementioned storage medium includes, but is not limited to, various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memory (ROM), random access memory (RAM), electrically erasable programmable ROM, registers, hard disks, multimedia cards, card-type memories (such as SD or DX memories), magnetic memories, removable disks, CD-ROMs, magnetic disks, or optical disks. Based on this, this application also provides a non-volatile storage medium storing a computer program, which, when executed by a processor, performs the steps of the method for accelerating optical circuit-switched service recovery as described in any of the above embodiments.

[0094] It is understood that if the method for accelerating optical circuit-switched service recovery in the above embodiments is implemented as a software functional unit and sold or used as an independent product, the computer software product may not need to be stored in a physical storage medium. For example, it can be directly transmitted to a computer or other device with information processing capabilities via a wired or wireless network to execute all or part of the steps of the methods in the various embodiments of this application. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the related technology, or all or part of the technical solution, can be embodied in the form of a software product. Based on this, this application also provides a computer program product storing a computer program, which, when executed by a processor, performs the steps of the method for accelerating optical circuit-switched service recovery as described in any of the above embodiments.

[0095] Any of the components, modules, units, parts, methods, and operations described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or any combination thereof. Alternatively or additionally, any functionality described herein can be performed at least in part by one or more hardware logic components, such as, but not limited to, a central processing unit (CPU), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), an application-specific standard product (ASSP), a system-on-a-chip (SoC), a complex programmable logic device (CPLD), a microprocessor (MCU), etc. The systems, computing devices, or apparatuses described herein encompass a wide range of means, devices, and machines for processing data, including, for example, one or more programmable processors, computers, SoCs, or combinations thereof. The apparatus may also include code that creates an execution environment for the computer program in question, such as code constituting processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or one or more combinations thereof. The aforementioned computer program (also known as a program, software, software application, app, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and can be deployed in any form, including as a standalone program or as a module, component, subroutine, object, or other unit suitable for a computing environment.

[0096] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this specification can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0097] The foregoing has provided a detailed description of a method, apparatus, electronic device, computer-readable storage medium, and computer program product for accelerating the recovery of optical circuit-switched services. The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Several improvements and modifications can be made to this application without departing from the principles thereof, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A method for accelerating the recovery of optical circuit-switched services, characterized in that, include: When it is determined that there is a need for optical path switching, before switching the optical path connection, a state switching command is sent to the source port and the destination port corresponding to the physical layer optical link to be established, so that the source port sending side and the destination port receiving side enter the fast link establishment state. In fast link establishment mode, the source port transmitting side sends an alignment mark to the destination port receiving side according to a first transmission interval, and the destination port receiving side detects the alignment mark according to the first transmission interval; the first transmission interval is less than the second transmission interval used by the destination port in normal working mode. The optical switching unit is controlled to perform an optical path switching operation to establish a physical layer optical link between the source port and the destination port; After the optical path switching operation is completed, the receiving side of the destination port detects the alignment mark from the transmitting side of the source port according to the first transmission interval, and determines that the link establishment is completed after detecting a preset number of valid alignment marks; After the link is established, the receiving side of the destination port and the sending side of the source port switch from the fast link establishment state to the normal working state.

2. The method for accelerating the recovery of optical circuit-switched services according to claim 1, characterized in that, During the optical path switching operation, the source port transmitting side continuously sends alignment markers; if the destination port receiving side detects optical signal loss or optical signal degradation during the optical path switching process, it resets the link establishment state to accelerate the entry into the unlocked state.

3. The method for accelerating the recovery of optical circuit-switched services according to claim 1, characterized in that, The second transmission interval is an integer multiple of the first transmission interval.

4. The method for accelerating the recovery of optical circuit-switched services according to claim 3, characterized in that, The first transmission interval is configured based on the duration of a single forward error correction codeword, using the duration of the forward error correction coding channel, the alternation period of the odd and even codewords, and the product of an adjustable positive integer coefficient.

5. The method for accelerating the recovery of optical circuit-switched services according to claim 1, characterized in that, The switching from fast link establishment state to normal operation state for both the destination port receiving side and the source port sending side includes: Once the connection establishment is completed, the receiving side of the destination port sends a connection establishment indication message to the receiving side of the source port through the sending side of the destination port, switching from the fast connection establishment state to the normal working state. Upon receiving the established link indication information, the source port sending side switches from the fast link establishment state to the normal working state.

6. The method for accelerating the recovery of optical circuit-switched services according to any one of claims 1 to 5, characterized in that, Before the receiving side of the destination port switches from the fast connection establishment state to the normal working state, it first enters a transition state. In the transition state, the source port transmitting side transmits an alignment mark at the first transmission interval or the second transmission interval, and the destination port receiving side simultaneously detects the alignment mark at both the first transmission interval and the second transmission interval; After detecting the alignment mark sent according to the second transmission interval, the receiving side of the destination port switches from the transition state to the normal operating state.

7. The method for accelerating the recovery of optical circuit-switched services according to any one of claims 1 to 5, characterized in that, Also includes: When a status recovery notification is received from the source port sending side or the destination port receiving side after switching to the normal working state, the successful connection establishment time is determined according to the status recovery notification. The business recovery time will be determined based on the successful chain establishment time and the chain establishment start time. Based on the service recovery time and time slot duration, the switching efficiency is determined, and the optical path scheduling parameters are optimized based on the switching efficiency.

8. The method for accelerating the recovery of optical circuit-switched services according to any one of claims 1 to 5, characterized in that, Send state switching commands to the source and destination ports corresponding to the physical layer optical link to be established, including: A state switching command carrying time information is sent to the source port and the destination port. When the timer reaches the time indicated by the time information, the source port sending side and the destination port receiving side enter the fast link establishment state.

9. The method for accelerating the recovery of optical circuit-switched services according to any one of claims 1 to 5, characterized in that, When an optical path switching requirement is determined, before switching the optical path connection, a state switching command is sent to the source port and destination port corresponding to the physical layer optical link to be established, including: Obtain the estimated establishment time of the physical layer optical link to be established: If the physical layer optical link to be established is being established for the first time, the initial establishment time corresponding to the physical layer optical link to be established is read from the initial reference data, and the initial establishment time is used as the estimated establishment time of the physical layer optical link to be established; the initial reference data is generated during initialization by traversing and configuring each physical layer optical link and based on the initial establishment time of each physical layer optical link obtained through training. If the physical layer optical link to be established is not being established for the first time, the historical link establishment data of the physical layer optical link to be established within the historical time period is read from the link establishment schedule, and the estimated link establishment time of the physical layer optical link to be established is determined based on the historical link establishment data; the link establishment schedule records the actual historical link establishment completion time and the corresponding link establishment start time of each physical layer optical link. Based on the bandwidth requirements of the service to be transmitted, the port rate, and the estimated link establishment time, the new time slot duration allocated to the physical layer optical link to be established is determined. Based on the new time slot duration, port rate, and estimated switching efficiency determined by the estimated link establishment time, calculate the estimated total amount of data to be transmitted within the new time slot duration, and determine the validity of the new time slot duration when the estimated total amount of data to be transmitted meets the bandwidth requirements. When the time slot corresponding to the new time slot duration begins, a state switching command is sent to the source port and destination port corresponding to the physical layer optical link to be established.

10. An apparatus for accelerating the recovery of optical circuit-switched services, characterized in that, It includes the inbound service terminal, optical circuit switching controller, optical circuit switching unit, and outbound service terminal; The link establishment accelerator at the inbound service end is connected to the optical circuit switching controller to receive state switching instructions and return the link establishment completion time; the physical medium connection sublayer or physical medium related sublayer at the inbound service end is connected to the optical circuit switching unit through a photoelectric converter. The optical circuit switching unit is connected to the optical circuit switching controller and is used to perform optical path switching operation after receiving a state switching command; The link establishment accelerator for the outgoing service end is connected to the optical circuit switching controller, and is used to receive state switching instructions and return the link establishment completion time; the physical medium connection sublayer or physical medium related sublayer for the outgoing service end is connected to the optical circuit switching unit through a photoelectric converter. The optical circuit switching controller is used to implement the corresponding steps of the method for accelerating optical circuit switching service recovery as described in any one of claims 1 to 9 when executing the computer program.

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