A hybrid flow scheduling method and device for intelligent substation based on time-sensitive network

Abstract

The present invention provides a hybrid traffic scheduling method and device for a smart substation based on a time-sensitive network. The terminal device sends the hybrid traffic to a switch through a link. Based on an active packet loss mechanism and a flexible queue entry strategy, the periodic traffic and the key non-periodic traffic are stored in a protection queue, and the non-key non-periodic traffic is stored in a non-protection queue. The data packets of the periodic traffic are preferentially transmitted. When there is no periodic traffic in the protection queue, the switch determines whether there is key non-periodic traffic. If so, the corresponding protection queue is opened to transmit the data packets of the key non-periodic traffic. If not, the non-protection queue is opened to transmit the data packets of the non-key non-periodic traffic. The hybrid traffic scheduling method provided by the present invention can reduce the expiration rate of data packets and improve the resource utilization of the switch.

Description

Technical Field

[0001] The present invention relates to the field of intelligent substation communication technology, and in particular to a hybrid flow scheduling method and device for an intelligent substation based on a time-sensitive network. Background Art

[0002] With the rapid development of power networks represented by smart substation technology, traditional bus networks are difficult to provide high-reliability, high-bandwidth real-time transmission for power systems. For example, the sampled measured value (SMV) traffic in the substation requires its transmission delay to be less than 3ms. In order to further improve the reliability of data transmission in smart grids, a large number of works have attempted to introduce Ethernet technology into power networks. However, Ethernet technology provides forwarding services for data packets on a best-effort basis and cannot provide deterministic transmission services with delay guarantees for critical traffic. Time-Sensitive Networking (TSN), as a standard Open Systems Interconnection (OSI) layer 2 technology with time determinism, has become a recognized solution in recent years that is expected to provide deterministic transmission for smart grids.

[0003] TSN ensures the deterministic behavior of critical traffic in network transmission by adopting a unified clock synchronization protocol and a strict traffic scheduling algorithm. TSN standard technology is mainly aimed at periodic critical traffic. However, according to IEC 61580, the only international standard for substation automation systems, there are three types of critical traffic in substations: sampled measurement value SMV traffic, Generic Object Oriented Substation Events (GOOSE) traffic, and Manufacturing Message Specification (MMS) traffic, among which SMV traffic is time-triggered periodic traffic, and GOOSE traffic and MMS traffic are non-periodic traffic. The key difference between periodic traffic and non-periodic traffic is that the occurrence of non-periodic traffic cannot be determined, and it is difficult to schedule it through traffic scheduling algorithms.

[0004] In TSN, in order to provide highly reliable services for mixed traffic consisting of periodic and non-periodic traffic, current work can be mainly divided into two categories. The first category of work designs special traffic scheduling algorithms for different scenarios, such as E-TSN designs a probability-based traffic scheduling algorithm for scenarios with known non-periodic traffic distribution. However, in smart grids, the generation of GOOSE traffic and MMS traffic is driven by events such as tripping events and log files, which are difficult to obtain in advance, so they are not applicable. The second category of work provides storage and forwarding services for non-periodic traffic by reserving additional storage resources and bandwidth for it. However, this type of work simply reserves certain resources and still uses the first-in-first-out principle to provide forwarding services for non-periodic traffic, without considering the characteristics of non-periodic traffic itself to provide differentiated forwarding services, so it has an extremely high packet expiration rate. In addition, switch resources are very scarce, and it is also very difficult to reserve appropriate resources for non-periodic traffic, which is likely to cause a huge waste of resources. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a hybrid traffic scheduling method and device for a smart substation based on a time-sensitive network to eliminate or improve one or more defects existing in the prior art, and to solve the problems of high data packet expiration rate, low switch resource utilization, and resource waste existing in the existing smart substation traffic scheduling technical solutions.

[0006] On the one hand, the present invention provides a hybrid flow scheduling method for a smart substation based on a time-sensitive network, the method comprising the following steps:

[0007] The terminal device sends mixed traffic to the switch through a link; the mixed traffic includes periodic traffic and non-periodic traffic; the periodic traffic and key non-periodic traffic are stored in a protection queue, and the non-key non-periodic traffic is stored in a non-protection queue;

[0008] Prioritize the transmission of data packets of the periodic traffic; when there is no periodic traffic in the protection queue, the switch determines whether there is the critical non-periodic traffic, if yes, opens the corresponding protection queue to transmit the data packets of the critical non-periodic traffic, if no, opens the non-protection queue to transmit the data packets of the non-critical non-periodic traffic;

[0009] Among them, when the data packet of the critical non-periodic traffic arrives at the switch, its remaining processing time is obtained, and the remaining processing time is compared with the shortest time required for it to reach the target node. If the remaining processing time is less than the shortest time, the data packet is discarded; if the remaining processing time is greater than or equal to the shortest time, the expected arrival time of the data packet at the next-hop switch is calculated, and if the actual arrival time at the next-hop switch is not later than the expected arrival time at the next-hop switch, the protection queue corresponding to the data packet is put into an expected queue set; if the expected queue set is not empty, the latest sent protection queue in the expected queue set is selected for the data packet; if it is empty, the earliest sent protection queue in the protection queue set is selected for the data packet.

[0010] In some embodiments of the present invention, before executing the method, the method further includes:

[0011] Collecting information of the periodic traffic and calculating a gating list according to a preset traffic planning algorithm;

[0012] The gating list is sent to the switch to open a corresponding protection queue for the periodic traffic according to the arrival time and the sending time of the periodic traffic.

[0013] In some embodiments of the present invention, modeling a smart substation network topology includes:

[0014] The time-sensitive network topology is abstracted into a graph; the graph includes nodes and edges, all terminal devices and switches are regarded as nodes, and the links between any nodes are regarded as edges;

[0015] The definition formula of the nodes and the edges is:

[0016] V = ES ∪ SE;

[0017] E={e j =(v j ,v i )||v j ,v i ∈V,i≠j};

[0018] Wherein, V represents the node set; ES represents the terminal device set; SE represents the switch set; E represents the edge set; e j Represents node v j To node v i link.

[0019] In some embodiments of the present invention, modeling the smart substation flow includes:

[0020] Assuming unicast traffic and the same link rate for all links, a non-periodic traffic is modeled as:

[0021] f i ={o i ,d i ,st i ,l i ,ddl i ,path i};

[0022] Among them, i Indicates the sending node; d i Indicates the target node; st i Indicates the sending time; i Indicates the time required for sending; ddl i Indicates the deadline; path i Represents a collection of path nodes.

[0023] In some embodiments of the present invention, obtaining the remaining processing time, comparing the remaining processing time with the shortest time required for the data packet to reach the target node, and discarding the data packet if the remaining processing time is less than the shortest time, further includes:

[0024] The remaining processing time is calculated according to the deadline time and current time of the data packet of the critical non-periodic traffic;

[0025] For any queue, determine whether the time length from the current time to the time of sending the next data packet is greater than or equal to the time required to send the data packet. If so, add the queue to the protection queue set that can accommodate the data packet;

[0026] Calculate the shortest time for the data packet to reach the target node; the shortest time includes the minimum queuing time of the data packet at the port, the minimum queuing time at the switch and the minimum transmission time on the link;

[0027] When the protection queue set is empty, the data packet is discarded; when the protection queue set is not empty, the remaining processing time and the shortest time are compared, and if the remaining processing time is less than the shortest time, the data packet is discarded; if the remaining processing time is not less than the shortest time, the method continues to be executed.

[0028] In some embodiments of the present invention, the shortest time includes the minimum queuing time of the data packet at the port, the minimum queuing time at the switch and the minimum transmission time on the link, and also includes:

[0029] The minimum queuing time at a port is calculated as:

[0030]

[0031] Among them, legalQueue i represents the protection queue set; Indicates link e j The time required for the data packet being sent by the vth protection queue to be sent starting from time rt;

[0032] The minimum transmission time on a link is the sum of the propagation delays of all links, calculated as:

[0033]

[0034] Among them, |path i |Represents the path node set path i The number of nodes in ; Indicates link e j In the non-periodic flow f i The index in the path; j' represents the node Corresponding output port; PD j' Indicates link e j' of propagation delay.

[0035] In some embodiments of the present invention, if the remaining processing time is greater than or equal to the shortest time, then calculating the expected arrival time of the data packet at the next hop switch further includes:

[0036] The calculation formula for the expected arrival time at the next hop switch is:

[0037]

[0038] Among them, st i Indicates the sending time; ave i Indicates the average time the data packet spends at each hop node; Indicates link e j+1 In the non-periodic flow f i The index in the path of

[0039] The average time that the data packet spends at each hop node is calculated based on the sending time and deadline of the data packet. The calculation formula is:

[0040]

[0041] Among them, st i Indicates the sending time; ddl i Indicates the deadline; |path i |Represents the path node set path i The number of nodes in .

[0042] In some embodiments of the present invention, a suitable protection queue is selected according to whether the expected queue set is empty. After the data packet enters the protection queue, the switch updates the sending time of the protection queue, and the calculation formula is:

[0043]

[0044] in; Indicates link e j Protection queue selection i The time required for the data packet being sent to be sent starting from time rt; l i Indicates the time required for sending.

[0045] On the other hand, the present invention also provides a hybrid flow scheduling device for a smart substation based on a time-sensitive network, the device comprising:

[0046] A traffic transmission module, used for a terminal device to send mixed traffic to a switch through a link; the mixed traffic includes periodic traffic and non-periodic traffic; the periodic traffic and key non-periodic traffic are stored in a protection queue, and the non-key non-periodic traffic is stored in a non-protection queue;

[0047] An active packet dropping module, configured to obtain the remaining processing time of the data packet of the critical non-periodic traffic when the data packet arrives at the switch, compare the remaining processing time with the shortest time required for the data packet to reach the target node, and discard the data packet if the remaining processing time is less than the shortest time;

[0048] A flexible queue entry module is used to calculate the expected arrival time of the data packet at the next-hop switch if the remaining processing time is greater than or equal to the shortest time, and if the actual arrival time at the next-hop switch is not later than the expected arrival time at the next-hop switch, put the protection queue corresponding to the data packet into the expected queue set; if the expected queue set is not empty, select the latest sent protection queue in the expected queue set for the data packet; if it is empty, select the earliest sent protection queue in the protection queue set for the data packet;

[0049] A traffic scheduling module is used to give priority to transmitting data packets of the periodic traffic; when the protection queue does not contain the periodic traffic, the switch determines whether there is the critical non-periodic traffic, and if so, opens the corresponding protection queue to transmit the data packets of the critical non-periodic traffic; if not, opens the non-protection queue to transmit the data packets of the non-critical non-periodic traffic.

[0050] On the other hand, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the methods mentioned above.

[0051] The beneficial effects of the present invention are at least:

[0052] The present invention provides a hybrid traffic scheduling method and device for a smart substation based on a time-sensitive network. The terminal device sends the hybrid traffic to the switch through a link; based on an active packet loss mechanism and a flexible queue entry strategy, the periodic traffic and the key non-periodic traffic are stored in a protection queue, and the non-key non-periodic traffic is stored in a non-protection queue; the data packets of the periodic traffic are preferentially transmitted; when there is no periodic traffic in the protection queue, the switch determines whether there is key non-periodic traffic, if so, the corresponding protection queue is opened to transmit the data packets of the key non-periodic traffic, if not, the non-protection queue is opened to transmit the data packets of the non-key non-periodic traffic. The hybrid traffic scheduling method provided by the present invention couples the attributes of the data packets of the non-periodic traffic with the queue entry logic, and utilizes the remaining queue resources of the periodic traffic to absorb the non-periodic traffic, effectively improving the resource utilization rate. Further, the design of the active packet loss mechanism can actively discard the data packets of the non-periodic traffic that has no hope of reaching the destination, reduce useless data transmission, and prompt the system efficiency. Further, the design of the flexible queue entry strategy can put the data packets of different non-periodic traffic into the appropriate queue, protect more urgent non-periodic traffic, and reduce the expiration rate of data packets.

[0053] Additional advantages, purposes, and features of the present invention will be described in part in the following description, and will become apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The purposes and other advantages of the present invention may be achieved and obtained by the structures specifically indicated in the specification and the accompanying drawings.

[0054] Those skilled in the art will appreciate that the objectives and advantages that can be achieved with the present invention are not limited to the above specific description, and the above and other objectives that can be achieved by the present invention will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute a limitation of the present invention. In the drawings:

[0056] Figure 1 The present invention is a schematic diagram of the steps of a hybrid flow scheduling method for a smart substation based on a time-sensitive network in one embodiment of the present invention.

[0057] Figure 2 It is a schematic diagram of an existing hybrid traffic scheduling technical solution in one embodiment of the present invention.

[0058] Figure 3 The figure is a schematic diagram of the overall structural flow of a hybrid flow scheduling method for a smart substation based on a time-sensitive network in one embodiment of the present invention.

[0059] Figure 4 The figure is a schematic diagram of the process (working principle) of a hybrid flow scheduling method for a smart substation based on a time-sensitive network in one embodiment of the present invention.

[0060] Figure 5 The figure is a flow chart of an active packet loss mechanism in one embodiment of the present invention.

[0061] Figure 6 The figure is a flow chart of a flexible queue entry strategy in one embodiment of the present invention. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0063] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0064] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0065] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection involving an intermediate.

[0066] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0067] It should be emphasized here that the step marks mentioned below are not intended to limit the order of the steps, but it should be understood that the steps can be executed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be executed simultaneously.

[0068] In order to solve the problems of high data packet expiration rate, low switch resource utilization and resource waste in the existing intelligent substation traffic scheduling technical solutions, the present invention proposes a hybrid traffic scheduling method for intelligent substation based on time-sensitive network, such as Figure 1 As shown, the method includes the following steps S101 to S103:

[0069] Step S101: The terminal device sends mixed traffic to the switch through a link, wherein the mixed traffic includes periodic traffic and non-periodic traffic.

[0070] Step S102: Based on the active packet loss mechanism and the flexible queue entry strategy, the periodic traffic and the key non-periodic traffic are stored in the protection queue, and the non-key non-periodic traffic is stored in the non-protection queue.

[0071] Step S103: Prioritize the transmission of data packets of periodic traffic; when there is no periodic traffic in the protection queue, the switch determines whether there is critical non-periodic traffic, if so, the corresponding protection queue is opened to transmit data packets of critical non-periodic traffic, if not, the non-protection queue is opened to transmit data packets of non-critical non-periodic traffic.

[0072] Among them, when the data packet of the critical non-periodic traffic arrives at the switch, its remaining processing time is obtained, and the remaining processing time is compared with the shortest time required for it to reach the target node. If the remaining processing time is less than the shortest time, the data packet is discarded; if the remaining processing time is greater than or equal to the shortest time, the expected arrival time of the data packet at the next hop switch is calculated, and if the actual arrival time at the next hop switch is not later than the expected arrival time at the next hop switch, the protection queue corresponding to the data packet is placed in the expected queue set; if the expected queue set is not empty, the protection queue with the latest transmission in the expected queue set is selected for the data packet; if it is empty, the protection queue with the earliest transmission in the expected queue set is selected for the data packet.

[0073] For a better understanding, the existing hybrid traffic scheduling technology solution based on time-sensitive network is further explained. The existing solution adopts additional queue space to accommodate non-periodic traffic, and the representative ones are EnhancedMulti-CQF and reTSN. When non-periodic traffic arrives, it is first placed in a dedicated queue space, and the remaining bandwidth of the periodic traffic is used to forward the non-periodic traffic without affecting the planned periodic traffic. Figure 2As shown in the figure, when periodic traffic arrives, it enters the queue (Q1, Q2 queue) specified by the traffic planning algorithm and is forwarded according to the sending time planned by the traffic planning algorithm; when non-periodic traffic arrives, it enters the queue reserved for it (Q3 queue) and uses the remaining bandwidth to send it when there is no periodic traffic to be forwarded. Although this solution can provide transmission services for non-periodic traffic in a large number of scenarios, the following two problems still exist: (1) Since the first-in-first-out (FIFO) principle is used to provide forwarding services for both periodic and non-periodic traffic, urgent non-periodic traffic data packets are easily blocked by other non-periodic traffic. Figure 2 As shown in Figure 1, when a non-periodic traffic data packet with a remaining time of 20 arrives, it will first enter Q3 and wait for transmission. The subsequent non-periodic traffic data packet with a remaining time of 5 will be blocked and expired. (2) When there is only a small amount of non-periodic traffic in the system, the reserved queue resources are mostly wasted, so the resource utilization of the switch is low.

[0074] Based on the defects of the above-mentioned prior art solutions, the present invention proposes a hybrid flow scheduling method for smart substations based on time-sensitive networks, such as Figure 3 As shown in the figure, the traffic of smart substation is divided into periodic traffic and non-periodic traffic. The active packet loss mechanism designed in the switch discards some data packets, and the data packets that are not discarded enter the corresponding TAS (TimeAware Shaper) queue through the flexible queue entry strategy.

[0075] like Figure 4 As shown, it is a flow chart of the hybrid flow scheduling method of smart substation based on time-sensitive network.

[0076] In step S101, the terminal device sends mixed traffic to the switch through a link.

[0077] In smart grid, it mainly includes sampled measured value (SMV) traffic, general object-oriented substation event (GOOSE) traffic and manufacturing message specification (MMS) traffic. Among them, SMV traffic is time-triggered periodic traffic, while GOOSE traffic and MMS traffic are non-periodic traffic that combines time triggering and event triggering. GOOSE traffic can be further divided according to business type, as shown in Table 1.

[0078] Table 1

[0079]

[0080] In the present invention, GOOSE 1A traffic is regarded as critical non-periodic traffic, and GOOSE 1B traffic and MMS traffic are regarded as non-critical non-periodic traffic.

[0081] In step S102, based on the active packet loss mechanism and the flexible queue entry strategy, periodic traffic and critical non-periodic traffic are stored in the protection queue, and non-critical non-periodic traffic is stored in the non-protection queue, that is, SMV traffic and GOOSE 1A traffic are stored in the protection queue, and MMS traffic and GOOSE 1B traffic are stored in the non-protection queue, and transmitted as best-effort traffic.

[0082] It should be noted that the TAS mechanism divides the entire transmission process into multiple equal-length time slots, each of which is further divided into a protection window and a non-protection window, where the protection window and the non-protection window correspond to the protection queue and the non-protection queue mentioned above, respectively. In comparison, SMV traffic and GOOSE 1A traffic are critical traffic, and transmission within the protection window can ensure the certainty of transmission, so they are placed in the protection queue, whereas other traffic is placed in the non-protection queue.

[0083] In step S103, the protection queue is used to preferentially transmit data packets of periodic traffic (SMV traffic); when there is no periodic traffic in the protection queue, the switch determines whether there is critical non-periodic traffic (GOOSE 1A traffic). If so, the corresponding protection queue is opened to transmit data packets of the critical non-periodic traffic; if not, the non-protection queue is opened to transmit data packets of non-critical non-periodic traffic (MMS traffic and / or GOOSE 1B traffic).

[0084] The active packet loss mechanism and flexible queue entry strategy mentioned in step S102 are further explained below.

[0085] Firstly, the smart substation network topology is modeled.

[0086] In some embodiments, the time-sensitive network topology is abstracted into a graph, which includes nodes and edges. For example, the graph is denoted as G=(V, E), all terminal devices and switches are regarded as nodes, and links between any nodes are regarded as edges, as shown in formula (1) and formula (2):

[0087] V=ES∪SE; (1)

[0088] E={e j =(v j ,v i )|v j ,v i ∈V,i≠j}; (2)

[0089] Where V represents the node set; ES represents the terminal device set; SE represents the switch set; E represents the edge (link) set; e j Represents node v j To node v i link.

[0090] Then the smart substation transmission queue is modeled.

[0091] The hybrid traffic scheduling method provided by the present invention works based on multiple protection queues, using multiple protection queues to simultaneously accept and forward periodic traffic and key non-periodic traffic. The core of the TAS mechanism lies in the gating list, which is used to open or close each queue at each time point.

[0092] In some embodiments, before executing the traffic scheduling method, periodic traffic information is first collected, and a gating list is calculated according to a preset traffic planning algorithm, and the obtained gating list is sent to all switches, so that the switches can open the corresponding queue at the time when the periodic traffic needs to be sent. At the same time, according to the gating list, the arrival time and sending time of the current egress periodic traffic can be obtained, and the appropriate queue can be further selected for the critical non-periodic traffic.

[0093] use Indicates link e j The length of time from time t to the next data packet sending time of the vth protection queue; use Indicates link e j The time required for the data packet being sent by the vth protection queue to be sent starting from time t. j The vth protection queue has no traffic being sent at time t, so let

[0094] Then the smart substation traffic is modeled.

[0095] Assuming unicast traffic and the same link rate for all links, a non-periodic flow f i Modeled as formula (3):

[0096] f i ={o i ,d i ,st i ,l i ,ddl i ,path i}; (3)

[0097] Among them, i Indicates the sending node; d i Indicates the target node; st i Indicates the sending time; i Indicates the time required for sending; ddl i Indicates the deadline; path i Represents a collection of path nodes.

[0098] The active packet loss mechanism designed in the present invention is mainly used to solve the problem of resource waste caused by expired traffic in smart substations. Figure 5 As shown, it is a flowchart of the active packet loss mechanism.

[0099] When a data packet of non-periodic traffic arrives at the switch, the switch determines whether the data packet has a hope of reaching the destination. If there is no hope of reaching the destination, the data packet is directly discarded. Indicates link e j In the non-periodic flow f i The active packet loss mechanism specifically includes the following steps S10210 to S10213:

[0100] Step S10210: Calculate the remaining processing time according to the deadline and current time of the data packet of the key non-periodic traffic, and the calculation formula is shown in formula (4):

[0101] remain i =ddl i -rt; (4)

[0102] Among them, ddl i Indicates the deadline; rt indicates the current time.

[0103] Step S10211: For any queue, it can be recorded as the queue set Q for port j j For each queue v in the queue, determine the length of time from the current time to the time when the next data packet is sent. Is it greater than or equal to the time required to send the data packet? i If yes, then add the queue v to the protection queue set legalQueue that can accommodate the data packet i .

[0104] Step S10212: If there is no protection queue that can accommodate the data packet, that is, the protection queue set is empty, then the data packet is discarded; if there is a protection queue that can accommodate the data packet, that is, the protection queue set is not empty, then the shortest time for the data packet to reach the target node is calculated. For example, the shortest time is recorded as least i The shortest time consists of three parts: the minimum queuing time of the data packet at the port, the minimum queuing time at the switch, and the minimum transmission time on the link. It should be noted that for simplicity, the queuing time of the data packet of non-periodic traffic at the subsequent switch is 0, that is, when the data packet arrives at the subsequent switch, it will be forwarded immediately.

[0105] In some embodiments, let minQueue iis the minimum queuing time of all protection queues in the protection queue set that can accommodate the data packet, and the calculation formula is shown in formula (5):

[0106]

[0107] Among them, legalQueue i Represents the protection queue set; Indicates link e j The time required for the data packet being sent by the vth protection queue to be sent starting from time rt.

[0108] In some embodiments, let minTrans i is the sum of the propagation delays of all subsequent links, and the calculation formula is shown in formula (6):

[0109]

[0110] Among them, |path i |Represents the path node set path i The number of nodes in ; Indicates link e j In the non-periodic flow f i The index in the path; j' represents the node Corresponding output port; PD j' Indicates link e j' of propagation delay.

[0111] Step S10213: After obtaining the shortest time, compare the remaining processing time and the shortest time. If the remaining processing time is less than the shortest time, it means that the data packet can no longer reach the target node before the deadline, and the data packet is discarded; if the remaining processing time is not less than the shortest time, continue to execute the subsequent flexible queue entry strategy.

[0112] In the present invention, a flexible queue entry strategy is designed according to the deadline of non-periodic traffic, path length and current queue resources to protect more urgent non-periodic traffic. Figure 6 As shown, it is a schematic diagram of the process of the flexible team entry strategy, which specifically includes the following steps S10220 to S10223:

[0113] Step S10220: The switch calculates the average time that the key non-periodic traffic data packet spends at each hop node according to the sending time and deadline of the data packet, and further calculates the expected arrival time of the data packet at the next hop switch.

[0114] In some embodiments, the average time a data packet spends at each hop node is calculated as shown in formula (7):

[0115]

[0116] Among them, st i Indicates the sending time; ddl i Indicates the deadline; |path i |Represents the path node set path i The number of nodes in .

[0117] The calculation formula for the expected arrival time of the data packet at the next hop switch is shown in formula (8):

[0118]

[0119] Among them, st i Indicates the sending time; ave i Indicates the average time the data packet spends at each hop node; Indicates link e j+1 In the non-periodic flow f i The index in the path of .

[0120] Step S10221: For the protection queue set legalQueuue that can accommodate the data packet i For each queue v in the queue, determine whether the actual arrival time of the data packet at the next hop switch is not later than the expected arrival time of the data packet at the next hop switch. If so, put the protection queue into the expected queue set posQueue i .

[0121] In some embodiments, the calculation formula for the time when the data packet actually arrives at the next-hop switch is shown in formula (9):

[0122]

[0123] Among them, rt represents the current time; Indicates link e j The time required for the data packet being sent by the vth protection queue to be sent starting from time rt; PD j Indicates link e j The propagation delay of i Indicates the time required for sending.

[0124] Step S10222: If the expected queue set is not empty, the switch selects the protection queue that is sent the latest in the expected queue set for the data packet, that is, The protection queue with the largest value; if the expected queue set is empty, the switch will select the protection queue set legalQueue that can accommodate the packet. i Select the protection queue that can be sent earliest for sending, that is, The protection queue with the smallest value.

[0125] Step S10223: Set the final selected protection queue as select i After the data packet enters the queue, the switch updates the protection queue select i The sending time is calculated as shown in formula (10):

[0126]

[0127] in; Indicates link e j Protection queue selection i The time required for the data packet being sent to be sent starting from time rt; l i Indicates the time required for sending.

[0128] Corresponding to the hybrid flow scheduling method of a smart substation based on a time-sensitive network, the present invention also provides a hybrid flow scheduling device of a smart substation based on a time-sensitive network, the device comprising:

[0129] The traffic transmission module is used for the terminal device to send mixed traffic to the switch through the link, wherein the mixed traffic includes periodic traffic and non-periodic traffic, and the periodic traffic and key non-periodic traffic are stored in the protection queue, and the non-key non-periodic traffic is stored in the non-protection queue.

[0130] The active packet loss module is used to obtain the remaining processing time of the data packet of the critical non-periodic traffic when it arrives at the switch, and compare the remaining processing time with the shortest time required for it to reach the target node. If the remaining processing time is less than the shortest time, the data packet is discarded.

[0131] The flexible queue entry module is used to calculate the expected arrival time of the data packet at the next-hop switch if the remaining processing time is greater than or equal to the shortest time. If the actual arrival time at the next-hop switch is not later than the expected arrival time at the next-hop switch, the protection queue corresponding to the data packet is placed in the expected queue set; if the expected queue set is not empty, the latest sent protection queue in the expected queue set is selected for the data packet; if it is empty, the earliest sent protection queue in the protection queue set is selected for the data packet.

[0132] The traffic scheduling module is used to give priority to the transmission of data packets of periodic traffic; when there is no periodic traffic in the protection queue, the switch determines whether there is critical non-periodic traffic. If so, the corresponding protection queue is opened to transmit the data packets of critical non-periodic traffic. If not, the non-protection queue is opened to transmit the data packets of non-critical non-periodic traffic.

[0133] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a hybrid flow scheduling method for a smart substation based on a time-sensitive network.

[0134] Corresponding to the above method, the present invention also provides a device, which includes a computer device, the computer device includes a processor and a memory, the memory stores computer instructions, the processor is used to execute the computer instructions stored in the memory, and when the computer instructions are executed by the processor, the device implements the steps of the method described above.

[0135] The embodiment of the present invention also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the aforementioned edge computing server deployment method are implemented. The computer-readable storage medium can be a tangible storage medium, such as a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a floppy disk, a hard disk, a removable storage disk, a CD-ROM, or any other form of storage medium known in the technical field.

[0136] In summary, the present invention provides a hybrid traffic scheduling method and device for a smart substation based on a time-sensitive network, wherein a terminal device sends a hybrid traffic to a switch through a link; based on an active packet loss mechanism and a flexible queue entry strategy, periodic traffic and critical non-periodic traffic are stored in a protection queue, and non-critical non-periodic traffic is stored in a non-protection queue; data packets of periodic traffic are transmitted preferentially; when there is no periodic traffic in the protection queue, the switch determines whether there is critical non-periodic traffic, and if so, opens the corresponding protection queue to transmit data packets of critical non-periodic traffic, and if not, opens the non-protection queue to transmit data packets of non-critical non-periodic traffic. The hybrid traffic scheduling method provided by the present invention couples the attributes of data packets of non-periodic traffic with the queue entry logic, and utilizes the remaining queue resources of periodic traffic to absorb non-periodic traffic, effectively improving resource utilization. Furthermore, the design of an active packet loss mechanism can actively discard data packets of non-periodic traffic that have no hope of reaching the destination, reduce useless data transmission, and improve system efficiency. Furthermore, designing a flexible queue entry strategy can put packets of different non-periodic traffic into appropriate queues, protect more urgent non-periodic traffic, and reduce the packet expiration rate.

[0137] It should be understood by those skilled in the art that the exemplary components, systems and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software or a combination of the two. Whether it is performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present invention are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link via a data signal carried in a carrier.

[0138] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0139] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0140] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hybrid flow scheduling method for smart substation based on time-sensitive network, characterized in that: The method comprises the following steps: The terminal device sends mixed traffic to the switch through a link; the mixed traffic includes periodic traffic and non-periodic traffic; the periodic traffic and key non-periodic traffic are stored in a protection queue, and the non-key non-periodic traffic is stored in a non-protection queue; Prioritize the transmission of data packets of the periodic traffic; when there is no periodic traffic in the protection queue, the switch determines whether there is the critical non-periodic traffic, if yes, opens the corresponding protection queue to transmit the data packets of the critical non-periodic traffic, if no, opens the non-protection queue to transmit the data packets of the non-critical non-periodic traffic; Among them, when the data packet of the critical non-periodic traffic arrives at the switch, its remaining processing time is obtained, and the remaining processing time is compared with the shortest time required for it to reach the target node. If the remaining processing time is less than the shortest time, the data packet is discarded; if the remaining processing time is greater than or equal to the shortest time, the expected arrival time of the data packet at the next-hop switch is calculated, and if the actual arrival time at the next-hop switch is not later than the expected arrival time at the next-hop switch, the protection queue corresponding to the data packet is put into an expected queue set; if the expected queue set is not empty, the latest sent protection queue in the expected queue set is selected for the data packet; if it is empty, the earliest sent protection queue in the protection queue set is selected for the data packet.

2. The hybrid flow scheduling method for smart substation based on time-sensitive network according to claim 1 is characterized in that: Before executing the method, the method further includes: Collecting information of the periodic traffic and calculating a gating list according to a preset traffic planning algorithm; The gating list is sent to the switch to open a corresponding protection queue for the periodic traffic according to the arrival time and the sending time of the periodic traffic.

3. The hybrid flow scheduling method for smart substation based on time-sensitive network according to claim 1 is characterized in that: Modeling of smart substation network topology, including: The time-sensitive network topology is abstracted into a graph; the graph includes nodes and edges, all terminal devices and switches are regarded as nodes, and the links between any nodes are regarded as edges; The definition formula of the nodes and the edges is: ； in, Represents a collection of nodes; represents the terminal device set; represents the switch set; represents a set of edges; Representation Node To Node link.

4. The hybrid flow scheduling method for smart substation based on time-sensitive network according to claim 3 is characterized in that: Modeling the flow of the smart substation includes: Assuming unicast traffic and the same link rate for all links, a non-periodic traffic is modeled as: ； in, Represents the sending node; represents the target node; Indicates the sending time; Indicates the time required for sending; Indicates the deadline; Represents a collection of path nodes.

5. The hybrid flow scheduling method for smart substation based on time-sensitive network according to claim 4 is characterized in that: Obtaining the remaining processing time, comparing the remaining processing time with the shortest time required for the data packet to reach the target node, and discarding the data packet if the remaining processing time is less than the shortest time, further comprising: The remaining processing time is calculated according to the deadline time and current time of the data packet of the critical non-periodic traffic; For any queue, determine whether the time length from the current time to the time of sending the next data packet is greater than or equal to the time required to send the data packet. If so, add the queue to the protection queue set that can accommodate the data packet; Calculate the shortest time for the data packet to reach the target node; the shortest time includes the minimum queuing time of the data packet at the port, the minimum queuing time at the switch and the minimum transmission time on the link; When the protection queue set is empty, the data packet is discarded; when the protection queue set is not empty, the remaining processing time and the shortest time are compared, and if the remaining processing time is less than the shortest time, the data packet is discarded; if the remaining processing time is not less than the shortest time, the method continues to be executed.

6. The hybrid flow scheduling method for smart substation based on time-sensitive network according to claim 5 is characterized in that: The shortest time includes the minimum queuing time of the data packet at the port, the minimum queuing time at the switch and the minimum transmission time on the link, and also includes: The minimum queuing time at a port is calculated as: ； in, represents the protection queue set; Indicates link No. The packets being sent by the protection queue are from time The time required to start sending; The minimum transmission time on a link is the sum of the propagation delays of all links, calculated as: ； in, Represents a set of path nodes The number of nodes in ; Indicates link In non-periodic traffic The index in the path of Representation Node The corresponding output port; Indicates link of propagation delay.

7. The hybrid flow scheduling method for smart substation based on time-sensitive network according to claim 4 is characterized in that: If the remaining processing time is greater than or equal to the shortest time, then calculating the expected arrival time of the data packet at the next hop switch, further comprising: The calculation formula for the expected arrival time at the next hop switch is: ； in, Indicates the sending time; Indicates the average time the data packet spends at each hop node; Indicates link In non-periodic traffic The index in the path of The average time that the data packet spends at each hop node is calculated based on the sending time and deadline of the data packet. The calculation formula is: in, Indicates the sending time; Indicates the deadline; Represents a set of path nodes The number of nodes in .

8. The hybrid flow scheduling method for smart substation based on time-sensitive network according to claim 1 is characterized in that: A suitable protection queue is selected according to whether the expected queue set is empty. After the data packet enters the protection queue, the switch updates the sending time of the protection queue, and the calculation formula is: ； in; Indicates link Protection queue The data packet being sent is from time The time required to start sending; Indicates the time required for sending.

9. A hybrid flow dispatching device for intelligent substation based on time-sensitive network, characterized in that: The device comprises: A traffic transmission module, used for a terminal device to send mixed traffic to a switch through a link; the mixed traffic includes periodic traffic and non-periodic traffic; the periodic traffic and key non-periodic traffic are stored in a protection queue, and the non-key non-periodic traffic is stored in a non-protection queue; An active packet dropping module, configured to obtain the remaining processing time of the data packet of the critical non-periodic traffic when the data packet arrives at the switch, compare the remaining processing time with the shortest time required for the data packet to reach the target node, and discard the data packet if the remaining processing time is less than the shortest time; A flexible queue entry module is used to calculate the expected arrival time of the data packet at the next-hop switch if the remaining processing time is greater than or equal to the shortest time, and if the actual arrival time at the next-hop switch is not later than the expected arrival time at the next-hop switch, put the protection queue corresponding to the data packet into the expected queue set; if the expected queue set is not empty, select the latest sent protection queue in the expected queue set for the data packet; if it is empty, select the earliest sent protection queue in the protection queue set for the data packet; A traffic scheduling module is used to give priority to transmitting data packets of the periodic traffic; when the protection queue does not contain the periodic traffic, the switch determines whether there is the critical non-periodic traffic, and if so, opens the corresponding protection queue to transmit the data packets of the critical non-periodic traffic; if not, opens the non-protection queue to transmit the data packets of the non-critical non-periodic traffic.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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