A flow group scheduling method in optoelectronic hybrid data center network

Abstract

The present invention discloses a flow group scheduling method in an optoelectronic hybrid data center network, and belongs to the field of network transmission technology. The method first divides the input traffic into flow groups according to business semantics, and then inputs the network topology structure. Secondly, based on the flow group information, the order of the flow groups is solved in combination with the characteristics of the optical circuit switch and the electrical packet switch port bandwidth to obtain an ordered flow group sequence. Finally, the flow groups and the sub-flows contained therein are scheduled according to the flow group sequence to optimize the transmission of the traffic in the optoelectronic hybrid network structure, reduce the completion time of the flow group transmission, and achieve the purpose of comprehensive optimization of the overall transmission. The present invention can optimize the scheduling and transmission process of the traffic in the optoelectronic hybrid structure, and can be applied to the scenarios of integrated services in data centers, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of network transmission, and in particular relates to a flow group scheduling method in an optoelectronic hybrid data center network. Background Art

[0002] In recent years, the scale of data centers has been getting larger and larger. Multiple applications running on multiple servers require low latency and high throughput. Although electrical packet switches are flexible and can make forwarding decisions at the granularity of a single packet, data centers that only use electrical packet switching are not suitable for meeting these requirements. Electrical packet switches generate a lot of heat, require more cooling, and have higher power consumption costs. Optical circuit switching technology has more advantages than electrical packet switching technology. First, optical links can support larger capacity and higher density. For physical layer transmission, optical circuit switches do not need to process packets and can directly transmit optical signals, so they can support almost any link rate. In addition, the power consumption of optical circuit switches is lower than that of electrical packet switches. Typically, in an optical circuit switching network, the core optical circuit switch is interconnected with multiple racks. In other words, the port of each circuit switch is connected to a top-of-rack switch, and each top-of-rack switch is connected to a group of servers. Optical circuit switches have port restrictions, that is, each input (output) port can set up to one circuit to the output (input) port at a time. Circuit switching is very suitable for the traffic pattern of data centers because the traffic in the data center is concentrated and only a few top-of-rack switches are hot for a period of time. However, each circuit configuration will have a non-negligible reconfiguration delay, ranging from tens of microseconds to tens of milliseconds. During circuit reconfiguration, no data can be transmitted on the affected ports, resulting in a decrease in the utilization of some circuits. This is the main limitation of optical circuit switches and motivates circuit scheduling strategies to achieve high circuit utilization. Therefore, when faced with some delay-sensitive flows, optical circuits cannot meet their latency requirements, so we also need the presence of electrical packet switches to meet the transmission of some delay-sensitive flows. Such a hybrid network structure can meet different business needs and greatly shorten the overall completion time. Using these observations, the researchers proposed a hybrid data center network architecture that provides higher throughput at a lower cost by combining high-speed optical circuit switching technology with traditional electrical packet switches.

[0003] A stream group represents a collection of independent streams with a common performance goal. For example, the Map data stream and the Reduce data stream in the classic MapReduce software architecture can be abstracted as concurrent streams. A stream group is defined by the endpoints and byte size of each stream in the stream group. A stream group can represent any communication mode, such as many-to-many, one-to-many, many-to-one, and one-to-one. However, in complex business scenarios, they do not only contain streams with the same performance goals, so in order to use the concept of hybrid streams to generalize streams with different performance goals. Summary of the invention

[0004] The object of the present invention is to provide a flow group scheduling method in an optoelectronic hybrid data center network, which aims to reduce transmission time and increase throughput, and ultimately achieves an improvement in overall flow transmission efficiency.

[0005] Technical solution: A flow group scheduling method in an optoelectronic hybrid data center network, the method first groups the traffic, then sorts the flow groups according to the transmission bottleneck of the switch port, and optimizes the process of traffic transmission in the optoelectronic hybrid network structure to improve the transmission efficiency, including the following steps:

[0006] (1) Divide the traffic into flow groups according to business semantics and traffic information, record the flow size and arrival time, and then input the network topology structure;

[0007] (2) Based on the minimum bottleneck priority sorting strategy, the flow group information and network topology structure in step (1) are taken as input, and according to the transmission bottleneck constraint of the switch port in the optoelectronic hybrid network structure, an ordered flow group sequence is solved; wherein, the sorting calculation process of the flow group sequence is as follows:

[0008] A flow group C k Need to transmit ∑ through input port i j d ij The amount of data is transmitted through output port j i d ij The amount of data, It represents the time required for the flow group to transmit traffic from switch port i to all other ports. k The bottleneck of k It is expressed as:

[0009]

[0010] Among them, x i Indicates whether the port is a port in the optical circuit switch that needs to transmit traffic, δ indicates the reconfiguration delay of the optical circuit switch, ∑ j x jδ represents the link reconfiguration delay time required to complete the traffic transmission of port i in the optical circuit switch;

[0011] (3) Based on the flow group sequence obtained in step (2), the flow scheduling problem is optimized and solved to achieve combinatorial optimization of the overall transmission.

[0012] Furthermore, in step (1), flow group C k The sets are divided according to the flow information, including flow groups sensitive to throughput and flow groups sensitive to delay, and the flows in the flow groups are independent of each other.

[0013] Among them, flow group C k The basis for determining the set based on the performance of the stream is:

[0014] Flows whose length is greater than or equal to the threshold ε are the flow group that is sensitive to throughput; based on the observation of flow length and transmission requirements, flows whose length is less than the threshold ε are the flow group that is sensitive to delay.

[0015] Furthermore, the transmission bottleneck constraints of the switch ports in the optical-electrical hybrid network structure described in step (2) include optical circuit switch port bandwidth constraints, electrical packet switch bandwidth constraints, and flow transmission constraints;

[0016] The mathematical expression of the optical circuit switch port bandwidth constraint is as follows:

[0017] b ij ≤B c

[0018] Among them, b ij represents the link bandwidth occupied from ingress port i to egress port j in the optical circuit switch, B C Indicates the maximum link bandwidth that the optical circuit switch can withstand;

[0019] The mathematical expression of the bandwidth constraint of the electrical packet switch is as follows:

[0020]

[0021]

[0022] Among them, Φ P is the port set of the electrical packet switch, b ij represents the bandwidth occupied from ingress port i to egress port j in the electrical packet switch, B P Indicates the maximum bandwidth that the electrical packet switch can withstand;

[0023] The mathematical representation of the flow transmission constraint is as follows:

[0024]

[0025] Where S f , E f are the start time and end time of the transmission of stream f, r f (t) is the transmission rate of flow f at time t, d f is the size of the stream f.

[0026] Furthermore, step (3) includes the following process:

[0027] (31) Establishing scheduling constraints for different switches in the optoelectronic hybrid network structure, including establishing constraints on optical circuit switch links and establishing flow transmission constraints on flow groups during the transmission process of the optical circuit switch:

[0028] The mathematical expression of the link establishment constraint of the optical circuit switch is as follows:

[0029]

[0030]

[0031] Among them, Φ C is the port set of the optical circuit switch, μ ij (t) indicates whether a link is established between input port i and output port j at time slot t;

[0032] The mathematical expression of the transmission constraints of the flow group during the transmission process of the optical circuit switch is as follows:

[0033]

[0034]

[0035] in, Indicates flow group C k Whether a transmission is made from input port i to output port j at time slot t, Represents a set of flow groups;

[0036] In the optoelectronic hybrid network structure, the priority strategy for querying the switch status is determined according to the performance requirement M in the flow group. k When the flow f in is transmitted in the optical-electrical hybrid network, the flow transmission process is divided into two cases: transmission in the optical circuit switch and transmission in the electrical packet switch. Among them, when transmitting in the optical circuit switch, the link establishment time requirement is considered, and the mathematical expression of the flow transmission constraint is:

[0037]

[0038] Among them, σ kf Indicates flow group C k Whether the flow f in S is transmitted using an optical circuit switch,f is the start time of the flow transmission. When the flow is transmitted in the optical circuit switch, it needs to experience a reconfiguration delay after the start time before it can be transmitted. f is the end time of the flow transmission, δ represents the reconfiguration delay of the optical circuit switch, i, j are the ingress and egress ports of the flow transmitted on the optical circuit switch, and m, n are the ingress and egress ports of the flow transmitted on the electrical packet switch;

[0039] (32) For throughput-sensitive traffic, the throughput of a flow group is equal to the sum of the throughputs of all its sub-flows. Sub-flows that have not completed transmission will not affect the throughput of sub-flows that have completed transmission. This method sets a throughput-sensitive flow as a flow group and schedules it as a unit. T Representing the average sum of all throughput-sensitive flow groups during their life cycle, the following mathematical relationship is obtained:

[0040]

[0041] Among them, d f Indicates the length of stream f, A f represents the arrival time of flow f, E f represents the transmission completion time of stream f, represents the set of all throughput-sensitive flow groups;

[0042] For delay-sensitive traffic, the performance indicator of delay-sensitive traffic is defined as the average completion time of all flow groups. is the set of all delay-sensitive flow groups, each flow group C k Completion time is the maximum completion time of all sub-flows, using M L Representing the sum of the completion times of all flow groups, the following mathematical relationship is obtained:

[0043]

[0044]

[0045] Under the premise of ensuring that the transmission constraints are met, the optimization goal is to reduce the transmission completion time of the flow group and improve the throughput to improve the overall transmission efficiency. The optimization problem is formalized as follows:

[0046] Minimize:ω L M L -ω T M T

[0047] Among them, ω L and ω T Indicates the weights of the two types of flow groups so that the performance indicator increments remain balanced;

[0048] (33) Based on the optimization theory, the mathematical expression of step (31) and the optimization problem constructed in step (32) are combined, and the flow groups divided in step (1) are used as data input to solve the optimal flow scheduling strategy, and then the ordered flow groups are transmitted in sequence.

[0049] Among them, step (32) determines the priority strategy for querying the switch status according to the performance requirement M in the flow group, which specifically includes the following process:

[0050] The port status table (PST) is introduced to indicate the port status of the optical circuit switch and the electrical packet switch. There are three states: port idle, port establishing link, and port transmitting traffic; electrical packet switch port status There are two states: port idle and port transmitting traffic. Whenever the port state changes due to events such as the flow being scheduled for transmission or the transmission being completed, the PST will be updated;

[0051] When the flow group to be scheduled is a throughput-sensitive flow group, first check the status of the input and output ports of the optical circuit switch If the port constraints are met, the link can be established and transmitted through the optical circuit switch; if the port constraints are not met, the port status of the electrical packet switch is checked. Whether the constraints are met, if yes, then the transmission is carried out; if not, then check the next flow;

[0052] When the flow group to be scheduled is a delay-sensitive flow group, the inbound and outbound port status of the optical circuit switch will be checked first. If there is a good link established, the transmission can be carried out through the optical circuit switch. If there is no good link established, check the port status of the electrical packet switch. Whether the constraints are met, if they are met, the transmission is carried out; if not, the next flow is checked.

[0053] Furthermore, in the method, the sub-flows within the flow group query the port status of the optical circuit switch and the electrical packet switch through the port status table during transmission, and different types of flow groups have different query strategies. Whenever the port status changes due to events such as the flow being scheduled for transmission or the transmission being completed, the PST will update the corresponding port status.

[0054] In the method, when a new flow group arrives or a flow group transmission is completed, the flow groups are reordered according to the bottlenecks of the current flow groups, according to the minimum bottleneck priority sorting strategy and the optoelectronic hybrid network structure, so that the updated ordered flow groups continue to be transmitted under the constraints of the port status tables of different switches.

[0055] Beneficial effects: Compared with the prior art, the present invention has the following three significant effects:

[0056] (1) The present invention proposes a flow group transmission bottleneck formula based on the switch port bandwidth in an optoelectronic hybrid network, and uses this formula as a sorting standard to more accurately sort the flow groups. The divided sets are more conducive to achieving efficient transmission of the flow groups.

[0057] (2) The present invention optimizes the flow scheduling problem, meets the transmission of flows of different performance requirements, and then optimizes the overall transmission performance as the goal. In terms of flow scheduling strategy, it ensures that the transmission efficiency meets the requirements of different services;

[0058] (3) The present invention determines the scheduling objective function for different types of flow groups and designs an efficient scheduling scheme for the optoelectronic hybrid network to reduce the overall transmission completion time. By combining high-speed optical circuit switching technology with traditional electrical packet switches, higher throughput is provided at a lower cost and better performance is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is a flowchart of the steps of the method of the present invention;

[0060] Figure 2 This is the optical-electrical hybrid network topology of the data center in the embodiment. DETAILED DESCRIPTION

[0061] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0062] The present invention provides a flow group scheduling method in an optoelectronic hybrid data center network, which belongs to the field of network transmission technology. In this method, the input traffic is first divided into flow groups according to business semantics, and then the network topology is input. Secondly, based on the flow group information, the order of the flow groups is solved in combination with the characteristics of the port bandwidth of the optical circuit switch and the electrical packet switch to obtain an ordered flow group sequence. Finally, the flow groups and the sub-flows contained therein are scheduled according to the flow group sequence to optimize the transmission of the traffic in the optoelectronic hybrid network structure, reduce the completion time of the flow group transmission, and achieve the purpose of comprehensive optimization of the overall transmission. The present invention can optimize the scheduling and transmission process of the traffic in the optoelectronic hybrid structure, and can be applied to scenarios of comprehensive services in data centers, etc.

[0063] like Figure 1As shown, a flow group scheduling method in an optoelectronic hybrid data center network first obtains the size, arrival time and other related information of each flow, divides the flow into two flow groups with different performance targets according to the flow information, then sorts the flow groups according to the transmission bottlenecks of the flow groups, and then optimizes the process of traffic transmission in the optoelectronic hybrid network structure, which can ultimately achieve the purpose of improving transmission efficiency. The implementation steps are as follows:

[0064] Step (1): Classify the traffic according to its information, aggregate independent single flows into flow groups with the same performance requirements, and record relevant information such as the size and arrival time of the flows in the flow group.

[0065] A flow group is a collection of flows with a common performance goal, for example, minimizing the transmission completion time of a flow or ensuring that flows meet a common deadline. The flows in a flow group are independent because the input of a flow does not depend on the output of another flow, and the endpoints of these flows can be in one or more machines. Traditional point-to-point flows are still flow groups with only one flow. Through a flow group, we can know the size of the sub-flows, transmission destination, arrival time and other related information.

[0066] A flow group C k The number of flows is fixed, and the generated flow groups have different performance targets, namely, flow groups sensitive to throughput and flow groups sensitive to delay. The performance target of the flow is determined by whether the length of the flow is greater than the threshold ε. Flows with a length greater than or equal to the threshold ε belong to the flow group sensitive to throughput. Based on the observation of the length of the flow and the transmission requirements, flows with a length less than the threshold ε often have certain requirements for transmission delay, so they belong to the flow group sensitive to delay.

[0067] Step (2): Based on the minimum bottleneck first sorting strategy, the relevant information of step (1) and the network topology are used as input, and the bandwidth constraints of different types of switches are mathematically represented. The transmission bottleneck of the flow group is determined according to the transmission bottleneck of the flow within the flow group, so as to solve the ordered flow group sequence;

[0068] Step (201): mathematically represent the transmission bottleneck constraints of the switch ports in the optical-electrical hybrid network, including basic constraints on network traffic transmission such as optical circuit switch port bandwidth constraints, electrical packet switch port bandwidth constraints, and flow transmission constraints.

[0069] Each flow must complete the transmission of the entire flow from the start time to the end time of the transmission. The completion of the transmission of all flows indicates the end of the transmission of the entire flow group. The mathematical expression of the flow transmission constraint is as follows:

[0070]

[0071] Where S f , Ef are the transmission start time and end time of stream f, r f (t) is the transmission rate of flow f at time t, d f is the size of flow f;

[0072] Under the premise of meeting the bandwidth constraints of the electrical packet switch ports, the flow can be transmitted instantly from the ingress port to the egress port, which can better meet the needs of delay-sensitive flows. The mathematical expression of the bandwidth constraints of the electrical packet switch is as follows:

[0073]

[0074]

[0075] Among them, Φ P is the port set of the electrical packet switch, b ij represents the bandwidth occupied from ingress port i to egress port j in the electrical packet switch, B P Indicates the maximum bandwidth that an electrical packet switch can withstand.

[0076] Optical circuit switches can provide higher bandwidth, but each port can only establish one link at a time. Similarly, the transmission of the optical circuit switch must also meet the corresponding bandwidth limit, that is, the bandwidth transmitted through the link is less than the link bandwidth. The mathematical expression of the circuit bandwidth constraint of the optical circuit switch is as follows:

[0077] i,j∈Φ C :b ij ≤B c

[0078] Among them, b ij represents the link bandwidth occupied from ingress port i to egress port j in the optical circuit switch, B C Indicates the maximum link bandwidth that the optical circuit switch can withstand.

[0079] Step (202): Sort the flow group sequence obtained in step (201) and formalize the optimization sorting problem.

[0080] The flow groups are sorted using the transmission bottleneck time of the flow at the switch port, because the bottleneck takes into account factors such as the length, width, and size of the flow group, which can better reflect the characteristics of the flow group compared to the shortest or narrowest priority. The transmission of the flow is limited by the port bandwidth, so different flow groups occupy the port for different times. The time that the flow group occupies the port is determined by the time each flow occupies the port, where the longest occupancy time of the port is the transmission bottleneck of the flow group. The transmission time of the port is mainly determined by the amount of data that the port needs to transmit and the port bandwidth. The transmission of the optical circuit port requires reconfiguration delay, and the corresponding reconfiguration time must be added when calculating the bottleneck. Each flow group needs to transmit ∑ j d ij The amount of data is transmitted through each output port j i d ij The data volume, bandwidth of optical circuit switch port and electrical packet switch port are different. We use Γ k To represent the flow group C k The transmission bottleneck of the flow group can be expressed as:

[0081]

[0082] Among them, x i Indicates whether the port is a port in the optical circuit switch that needs to transmit traffic, δ indicates the reconfiguration delay of the optical circuit switch, ∑ j x j δ represents the link reconfiguration delay time required to complete the traffic transmission of port i in the optical circuit switch.

[0083] Step (203): Combine the port bandwidth constraint proposed in step (201) with the sorting problem constructed in step (202), use the flow group data in step (1) as input, sort the flow group sequence, and solve for the ordered flow group sequence.

[0084] Step (3): Based on the flow group sequence obtained in step (2), under the constraints of the port status table (PST) of different switches, driven by events such as flow transmission completion, the flow scheduling problem is optimized and solved to reduce the overall transmission time of the flow group, improve the throughput, and ultimately achieve the purpose of combined optimization of the overall transmission.

[0085] Specifically, the following steps are included:

[0086] Step (301): mathematically represent the constraints of the switch during the flow scheduling process. In the optoelectronic hybrid network structure, the optical circuit switch port can only establish one link at a certain time. During the transmission period, the port can only transmit data through this link. From this, the mathematical representation of the optical circuit switch port establishment constraints can be obtained:

[0087]

[0088]

[0089] Among them, Φ C is the port set of the optical circuit switch, μ ij (t) indicates whether a link is established between input port i and output port j at time slot t.

[0090] The optical circuit switch cannot transmit flows during the link reconfiguration period, and the port where the circuit is being established cannot be used by other flows. Therefore, it is necessary to set constraints on the transmission during the link establishment period of the optical circuit switch, that is, the constraints on the transmission of flow groups in the optical circuit switch:

[0091]

[0092]

[0093] in, Indicates flow group C k Whether a transmission is made from input port i to output port j at time slot t, Indicates the current stream group.

[0094] In the optical-electrical hybrid network structure, the performance requirement M in the flow group determines the priority strategy for querying the switch status. The port state table (PST) is introduced to represent the port status of the optical circuit switch and the electrical packet switch. There are three states: port idle, port establishing link, and port transmitting traffic. There are two states: port idle and port transmitting traffic. Whenever the port state changes due to events such as flow being scheduled for transmission or transmission completion, PST will be updated.

[0095] When the flow group to be scheduled is a throughput-sensitive flow group, the ingress and egress port status of the optical circuit switch will be checked first. If the port constraints are met, the link can be established and transmitted through the optical circuit switch. If the port constraints are not met, the port status of the electrical packet switch is checked. Whether the constraints are met, if they are met, the transmission is carried out; if not, the next flow is checked.

[0096] When the flow group to be scheduled is a delay-sensitive flow group, the inbound and outbound port status of the optical circuit switch will be checked first. If there is a good link established, the transmission can be carried out through the optical circuit switch. If there is no good link established, check the port status of the electrical packet switch. Whether the constraints are met, if they are met, the transmission is carried out; if not, the next flow is checked.

[0097] It is further pointed out that in the optoelectronic hybrid network structure, the flows in the flow group can be transmitted using an optical circuit switch or an electrical packet switch, but the transmission of the entire flow must be completed. When describing the transmission process of the flow in the optoelectronic hybrid network, variables are needed to indicate which switch is used for each flow in the flow group. At the same time, considering the transmission constraints during port establishment, the constraints for the flow transmission in the optoelectronic hybrid network structure are:

[0098]

[0099] Among them, σ kf Indicates flow group C k Whether the flow f in S is transmitted using an optical circuit switch, f is the start time of the flow transmission. When the flow is transmitted in the optical circuit switch, it needs to experience a reconfiguration delay after the start time before it can be transmitted. f is the end time of the flow transmission, δ represents the reconfiguration delay of the optical circuit switch, i, j are the ingress and egress ports of the flow transmitted on the optical circuit switch, and m, n are the ingress and egress ports of the flow transmitted on the electrical packet switch.

[0100] Step (302): For throughput-sensitive traffic, the throughput of a flow group is equal to the sum of the throughputs of all its sub-flows. Sub-flows that have not completed transmission will not affect the throughput of sub-flows that have completed transmission. That is, we make a throughput-sensitive flow a flow group and schedule it as a unit. T Represents the average sum of all throughput-sensitive flow groups during their lifetime:

[0101]

[0102] Among them, d f Indicates the length of stream f, A f represents the arrival time of flow f, E f represents the transmission completion time of stream f, Represents the set of all throughput-sensitive flow groups.

[0103] For delay-sensitive traffic, the performance indicator of delay-sensitive traffic is defined as the average completion time of all flow groups. is the set of all delay-sensitive flow groups, each flow group C k Completion time is the maximum completion time of all sub-flows. L Represents the sum of the completion times of all flow groups:

[0104]

[0105]

[0106] Under the premise of ensuring that the transmission constraints are met, the optimization goal is to reduce the transmission completion time of the flow group and improve the throughput to improve the overall transmission efficiency. The optimization problem is formalized as follows:

[0107] Minimize:ω L M L -ω T M T

[0108] Among them, ω L and ω T Indicates the weights of the two types of flow groups so that the performance indicator increments remain balanced.

[0109] Step (303): Based on the optimization theory as a solution method, the mathematical expression of step (301) and the optimization problem constructed in step (302) are combined, and step (1) is used as the data input to solve the optimal flow scheduling strategy, and then the ordered flow groups are transmitted in sequence.

[0110] The sub-flows within the flow group query the port status of the optical circuit switch and the electrical packet switch through the port state table (PST) during transmission. Different types of flow groups have different query strategies. Whenever the port status changes due to events such as the flow being scheduled for transmission or the transmission being completed, the PST will update the corresponding port status.

[0111] When a new flow group arrives or a flow group transmission is completed, the present invention will reorder the flow groups according to the bottlenecks of the current flow groups, according to the minimum bottleneck priority sorting strategy and the optoelectronic hybrid network structure, so that the updated ordered flow groups continue to be transmitted under the constraints of the port state tables (PST) of different switches.

[0112] Finally, the optimization is completed, and the purpose of improving the overall mixed traffic transmission efficiency is achieved according to the method described in the present invention.

Claims

1. A flow group scheduling method in an optoelectronic hybrid data center network, characterized in that: The method first groups the traffic, then sorts the traffic groups according to the transmission bottleneck of the switch port, and optimizes the process of traffic transmission in the optoelectronic hybrid network structure to improve the transmission efficiency, including the following steps: (1) Divide the traffic into flow groups according to business semantics and traffic information, and record the flow size and arrival time for input into the network topology; The flows include flow groups that are sensitive to throughput and flow groups that are sensitive to delay, and flows in the flow groups are independent of each other; Flow Group C k The way to divide the collection according to the flow information is as follows: The flows whose length is greater than or equal to the threshold ε are the flow groups that are sensitive to throughput. Based on the observation of the flow length and transmission requirements, the flows whose length is less than the threshold ε are the flow groups that are sensitive to delay. (2) Based on the minimum bottleneck priority sorting strategy, the flow group information and network topology structure in step (1) are taken as input, and according to the transmission bottleneck constraint of the switch port in the optoelectronic hybrid network structure, an ordered flow group sequence is solved; wherein, the sorting calculation process of the flow group sequence is as follows: A flow group C k Need to transmit ∑ through input port i j d ij The amount of data is transmitted through output port j i d ij The amount of data, It represents the time required for the flow group to transmit traffic from switch port i to all other ports. k The bottleneck of k It is expressed as: Among them, x i Indicates whether the port is a port in the optical circuit switch that needs to transmit traffic, δ indicates the reconfiguration delay of the optical circuit switch, ∑ j x j δ represents the link reconfiguration delay time required to complete the traffic transmission of port i in the optical circuit switch; The transmission bottleneck constraints of the switch ports in the optical-electrical hybrid network structure include optical circuit switch port bandwidth constraints, electrical packet switch bandwidth constraints and flow transmission constraints; The mathematical expression of the optical circuit switch port bandwidth constraint is as follows: b ij ≤B c Among them, b ij represents the link bandwidth occupied from ingress port i to egress port j in the optical circuit switch, B C Indicates the maximum link bandwidth that the optical circuit switch can withstand; The mathematical expression of the bandwidth constraint of the electrical packet switch port is as follows: Among them, Φ P is the port set of the electrical packet switch, b ij represents the bandwidth occupied from ingress port i to egress port j in the electrical packet switch, B P Indicates the maximum bandwidth that the electrical packet switch can withstand; The mathematical representation of the flow transmission constraint is as follows: Where S f , E f are the start time and end time of the transmission of stream f, r f (t) is the transmission rate of flow f at time t, d f is the size of flow f; (3) Based on the flow group sequence obtained in step (2), the flow scheduling problem is optimized and solved to achieve combined optimization of the overall transmission, including the following process: (31) Establish scheduling constraints for different switches in the optoelectronic hybrid network structure, including establishing constraints on optical circuit switch links and establishing flow transmission constraints on flow groups during the transmission process of the optical circuit switch: The mathematical expression of the optical circuit switch link establishment constraint is as follows: Among them, Φ C is the port set of the optical circuit switch, μ ij (t) indicates whether a link is established between input port i and output port j at time slot t; The mathematical expression of the transmission constraints of the flow group during the transmission process of the optical circuit switch is as follows: in, Indicates flow group C k Whether a transmission is made from input port i to output port j at time slot t, Represents a set of flow groups; In the optoelectronic hybrid network structure, the priority strategy for querying the switch status is determined according to the performance requirement M in the flow group. k When the flow f in is transmitted in the optical-electrical hybrid network, the flow transmission process is divided into two cases: transmission in the optical circuit switch and transmission in the electrical packet switch. Among them, when transmitting in the optical circuit switch, the link establishment time requirement is considered, and the mathematical expression of the flow transmission constraint is: Among them, σ kf Indicates flow group C k Whether the flow f in S is transmitted using an optical circuit switch, f is the start time of the flow transmission. When the flow is transmitted in the optical circuit switch, it needs to experience a reconfiguration delay after the start time before transmission. E f is the end time of the flow transmission, δ represents the reconfiguration delay of the optical circuit switch, i, j are the ingress and egress ports of the flow transmitted on the optical circuit switch, and m, n are the ingress and egress ports of the flow transmitted on the electrical packet switch; (32) For throughput-sensitive traffic, the throughput of a flow group is equal to the sum of the throughputs of all its sub-flows. Sub-flows that have not completed transmission will not affect the throughput of sub-flows that have completed transmission. This method sets a throughput-sensitive flow as a flow group and schedules it as a unit. T Representing the average sum of all throughput-sensitive flow groups during their life cycle, the following mathematical relationship is obtained: Among them, d f Indicates the length of stream f, A f represents the arrival time of flow f, E f represents the transmission completion time of stream f, represents the set of all throughput-sensitive flow groups; For delay-sensitive traffic, the performance indicator of delay-sensitive traffic is defined as the average completion time of all flow groups. is the set of all delay-sensitive flow groups, each flow group C k Completion time is the maximum completion time of all sub-flows, using M L Representing the sum of the completion times of all flow groups, the following mathematical relationship is obtained: Under the premise of ensuring that the transmission constraints are met, the optimization goal is to reduce the transmission completion time of the flow group and improve the throughput to improve the overall transmission efficiency. The optimization problem is formalized as follows: Minimize:oh L M L -oh T M T Among them, ω L and ω T Indicates the weights of the two types of flow groups so that the performance indicator increments remain balanced; (33) Based on the optimization theory as a solution method, the mathematical expression of step (31) and the optimization problem constructed in step (32) are combined, and the flow groups divided in step (1) are used as data input to solve the optimal flow scheduling strategy, and then the ordered flow groups are transmitted in sequence; The above step (32) determines the priority strategy for querying the switch status according to the performance requirement M in the flow group, and specifically includes the following process: The port status table is introduced to represent the port status of the optical circuit switch and the electrical packet switch, wherein the port status of the optical circuit switch is There are three states: port idle, port establishing link, and port transmitting traffic; electrical packet switch port status There are two states: port idle and port transmitting traffic. Whenever the port state changes due to events such as the flow being scheduled for transmission or the transmission being completed, the PST will be updated; When the flow group to be scheduled is a throughput-sensitive flow group, first check the status of the input and output ports of the optical circuit switch If the port constraints are met, a link is established and transmitted through the optical circuit switch; if the port constraints are not met, the port status of the electrical packet switch is checked. Whether the constraints are met, if yes, then the transmission is carried out; if not, then check the next flow; When the flow group to be scheduled is a delay-sensitive flow group, the inbound and outbound port status of the optical circuit switch will be checked first. If a link is established, the transmission is carried out through the optical circuit switch; if no link is established, the port status of the electrical packet switch is checked. Whether the constraints are met, if they are met, the transmission is carried out; if not, the next flow is checked.

2. The flow group scheduling method in the optoelectronic hybrid data center network according to claim 1 is characterized in that: In the method, the sub-flows within the flow group query the port status of the optical circuit switch and the electrical packet switch through the port status table during transmission. Different types of flow groups will have different query strategies. Whenever the port status changes due to events such as the flow being scheduled for transmission or the transmission being completed, the PST will update the corresponding port status.

3. The flow group scheduling method in the optoelectronic hybrid data center network according to claim 1, characterized in that: In the method, when a new flow group arrives or a flow group transmission is completed, the flow groups are reordered according to the bottlenecks of the current flow groups, according to the minimum bottleneck priority sorting strategy and the optoelectronic hybrid network structure, so that the updated ordered flow groups continue to be transmitted under the constraints of the port status tables of different switches.

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