Network topology determination method and apparatus, device, and computer readable storage medium

Abstract

The present application relates to the technical field of communications, and discloses a network topology determination method and apparatus, a device, and a computer readable storage medium. The method comprises: determining a first route calculation algorithm on the basis of first time, the first route calculation algorithm comprising first valid time information and a first network topology constraint, the first valid time information comprising valid time of the first route calculation algorithm, and the first time being earlier than the valid time of the first route calculation algorithm; and on the basis of the first valid time information and the first network topology constraint, determining a first network topology used at the valid time of the first route calculation algorithm, the first route calculation algorithm and the first network topology being determined before the valid time of the first route calculation algorithm. In the method, the first network topology determined in advance can be directly used at the valid time of the first route calculation algorithm, improving the efficiency of determining the first network topology, thereby improving the efficiency of calculating route information of the first network topology on the basis of the route calculation algorithm.

Description

Method, device, equipment and computer-readable storage medium for determining network topology

[0001] This application claims priority to Chinese patent application No. 202310787428.4 filed on June 29, 2023, entitled “A time-varying network routing method, device and system”, and Chinese patent application No. 202310919266.5 filed on July 24, 2023, entitled “Network topology determination method, device, equipment and computer-readable storage medium”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a method, apparatus, device, and computer-readable storage medium for determining a network topology. Background Art

[0003] With the development of communication technology, network requirements for different services or scenarios have become increasingly diverse. Consequently, flexible algorithms (flex-algo) and multi-topology algorithms, which perform routing calculations based on network topology constraints, have emerged. Different routing algorithms can determine different network topologies based on different network topology constraints, and thus can calculate routing information for different network topologies. Therefore, before calculating routes based on any routing algorithm, it is necessary to first determine the network topology for that algorithm.

[0004] Summary of the Invention

[0005] The present application provides a method, apparatus, device and computer-readable storage medium for determining a network topology, which are used to determine a network topology used at the effective time of a routing calculation algorithm before the effective time of the routing calculation algorithm.

[0006] In a first aspect, a method for determining a network topology is provided. The method determines a first routing calculation algorithm based on a first time, the first routing calculation algorithm includes first effective time information and a first network topology constraint, the first effective time information includes the effective time of the first routing calculation algorithm, the first effective time information and the first network topology constraint are used to determine the network topology corresponding to the first routing calculation algorithm, and the first time is before the effective time of the first routing calculation algorithm; based on the first effective time information and the first network topology constraint, a first network topology to be used at the effective time of the first routing calculation algorithm is determined, and the first routing calculation algorithm and the first network topology are determined before the effective time of the first routing calculation algorithm.

[0007] The method adds first validity period information to a first routing calculation algorithm so that the first routing calculation algorithm becomes effective at the validity period of the first routing calculation algorithm. Furthermore, by determining in advance before the validity period of the first routing calculation algorithm a first network topology to be used at the validity period of the first routing calculation algorithm, the method enables the first network topology determined in advance to be directly used at the validity period of the first routing calculation algorithm. This improves the efficiency of determining the first network topology and further improves the efficiency of calculating routing information of the first network topology based on the first routing calculation algorithm.

[0008] In one possible implementation, after determining the first network topology to be used during the effective time of the first route calculation algorithm based on the first effective time information and the first network topology constraint, first route information for the first network topology is calculated based on the first route calculation algorithm at a second time, where the second time is before the effective time of the first route calculation algorithm. The difference between the second time and the effective time of the first route calculation algorithm is less than a difference threshold. The difference threshold can be flexibly adjusted based on the application scenario. For example, the difference threshold can be a small value so that the second time is closer to the effective time of the first route calculation algorithm. Since the first route calculation algorithm calculates routes within the first network topology, the first route information is used to forward packets within the first network topology.

[0009] Therefore, the first routing information of the first network topology can be calculated in advance based on the routing calculation algorithm before the effective time of the first routing calculation algorithm, so that the first routing information calculated in advance can be directly used to forward messages during the effective time of the first routing calculation algorithm, and there is no need to calculate the first routing information during the effective time of the first routing calculation algorithm. This improves the efficiency of message forwarding based on the first routing information and avoids packet loss during the process of calculating the first routing information.

[0010] In one possible implementation, the effective time of the first routing calculation algorithm corresponds to the effective time of the first network topology. That is, the effective time of the first routing calculation algorithm can be determined based on the effective time of the first network topology. For scenarios where the network connection state changes, the network topology before and after the change in network connection state is different, i.e., different time periods correspond to different network topologies. In other words, any network topology is valid within the corresponding effective time period, and the effective time period refers to the time period between the effective time and the expiration time. Therefore, the effective time of the first routing calculation algorithm corresponds to the effective time of the first network topology, and the network topology can be switched by switching the routing calculation algorithm, thereby avoiding packet loss caused by changes in the network topology.

[0011] In one possible implementation, the first effective time information also includes a change period of the effective time of the first routing calculation algorithm, and the change period of the effective time of the first routing calculation algorithm corresponds to the change period of the effective time of the first network topology. By carrying the change period of the effective time in the first effective time information, the first routing calculation algorithm can be periodically effective, thereby improving the flexibility of the time constraints of the first routing calculation algorithm. In addition, the change period of the effective time of the first routing calculation algorithm corresponds to the change period of the effective time of the first network topology, so that by periodically switching the routing calculation algorithm, periodic switching of the network topology can be achieved, avoiding packet loss caused by using the first routing calculation algorithm outside the effective time of the first network topology.

[0012] In one possible implementation, the first network topology constraint includes a link color constraint. The link color constraint is used to constrain the colors of links included in the first network topology. Different colors are used to distinguish different validity periods. The colors of the links included in the first network topology comply with the link color constraint. By coloring links differently for different validity periods, the link color constraint allows the first network topology corresponding to a specified color to be determined. The first network topology is valid during the validity period indicated by the specified color.

[0013] In one possible implementation, the method further determines a second route calculation algorithm based on a third time. The second route calculation algorithm includes second validity time information and a second network topology constraint. The second validity time information indicates the validity time of the second route calculation algorithm. The second validity time information and the second network topology constraint are used to determine the network topology corresponding to the second route calculation algorithm. The third time is before the validity time of the second route calculation algorithm, and the validity time of the first route calculation algorithm and the validity time of the second route calculation algorithm are different. Based on the second validity time information and the second network topology constraint, a second network topology to be used during the validity time of the second route calculation algorithm is determined. The second route calculation algorithm and the second network topology are determined before the validity time of the second route calculation algorithm. By defining different route calculation algorithms corresponding to different validity times, the method makes the application of the route calculation method more flexible.

[0014] In one possible implementation, the first validity period information also includes a change period of the validity period of the first routing calculation algorithm, where the change period of the validity period of the first routing calculation algorithm is determined based on the first validity period information and the second validity period information. In the case of multiple routing calculation algorithms with different validity periods, the change period of the validity period of each routing calculation algorithm can be determined based on the validity period information of each routing calculation algorithm, thereby enabling periodic and cyclic use of the multiple routing calculation algorithms.

[0015] In a possible implementation, the first routing calculation algorithm may be a flex-algo or a multi-topology algorithm.

[0016] In the case where the first route calculation algorithm is flex-algo, before determining the first route calculation algorithm according to the first time, an intermediate system to intermediate system (ISIS) link state protocol data unit (Link State PDU, LSP) message for announcing the first route calculation algorithm may also be received, the first route calculation algorithm being carried in a flexible algorithm define (FAD) sub-TLV field of the ISIS LSP message, and the first validity time information being carried in a validity time sub-TLV field of the FAD sub-TLV; or, an open shortest path first (OSPF) link state advertisement (Link State Advertisement, LSA) message for announcing the first route calculation algorithm is received, the first route calculation algorithm being carried in a FAD TLV field of the OSPF LSA message, and the first validity time information being carried in a validity time sub-TLV field of the FAD TLV; or, a border gateway protocol (BGP) update message for announcing the first route calculation algorithm is received, the first route calculation algorithm being carried in a FAD TLV field of the BGP update message. In the TLV field, the first valid time information is carried in the valid time sub-TLV field of the FAD TLV.

[0017] This method provides multiple ways to announce flexible algorithms and also provides ways to carry information about the validity period of flexible algorithms, ensuring the implementation of this method. PDU stands for protocol data unit, TLV stands for type, length, and value, and sub-TLV stands for subtype, length, and value.

[0018] When the first route calculation algorithm is a multi-topology algorithm, before determining the first route calculation algorithm according to the first time, an ISIS LSP message for announcing the first route calculation algorithm may also be received, where the first route calculation algorithm is carried in a time-varying multi-topology (MT) information sub-TLV field of the ISIS LSP message, and the first validity time information is carried in a validity time sub-TLV field of the time-varying MT information sub-TLV; or, an OSPF LSA message for announcing the first route calculation algorithm is received, where the first route calculation algorithm is carried in a time-varying MT information TLV field of the OSPF LSA message, and the first validity time information is carried in a validity time sub-TLV field of the time-varying MT information TLV; or, a BGP update message for announcing the first route calculation algorithm is received, where the first route calculation algorithm is carried in a time-varying MT information TLV field of the BGP update message, and the first validity time information is carried in a validity time sub-TLV field of the time-varying MT information TLV.

[0019] The method provides multiple ways to notify the multi-topology algorithm and also provides ways to carry the effective time information of the multi-topology algorithm, thereby providing a guarantee for the implementation of the method.

[0020] In the second aspect, a device for determining a network topology is provided, which includes: a processing module for performing operations other than the operations related to receiving and / or sending in the first aspect or any possible implementation of the first aspect; and a transceiver module for performing operations related to receiving and / or sending in the first aspect or any possible implementation of the first aspect.

[0021] In a possible implementation, the transceiver module includes a receiving module and / or a sending module. The receiving module is used to perform reception-related operations, and the sending module is used to perform transmission-related operations.

[0022] In one possible implementation, a processing module is configured to determine a first routing calculation algorithm based on a first time, the first routing calculation algorithm including first effective time information and a first network topology constraint, the first effective time information including an effective time of the first routing calculation algorithm, the first effective time information and the first network topology constraint being used to determine a network topology corresponding to the first routing calculation algorithm, the first time being before the effective time of the first routing calculation algorithm; and determine a first network topology to be used at the effective time of the first routing calculation algorithm based on the first effective time information and the first network topology constraint, the first routing calculation algorithm and the first network topology being determined before the effective time of the first routing calculation algorithm.

[0023] In a possible implementation, the processing module is further configured to calculate first routing information of the first network topology based on the first routing calculation algorithm at a second time, where the second time is before the effective time of the first routing calculation algorithm.

[0024] In a possible implementation, the validity period of the first routing calculation algorithm corresponds to the validity period of the first network topology.

[0025] In a possible implementation, the first validity period information further includes a change period of the validity period of the first routing calculation algorithm, and the change period of the validity period of the first routing calculation algorithm corresponds to the change period of the validity period of the first network topology.

[0026] In a possible implementation, the first network topology constraint includes a link color constraint, which is used to constrain the colors of links included in the first network topology. Different colors are used to distinguish different valid times, and the colors of the links included in the first network topology comply with the link color constraint.

[0027] In one possible implementation, the processing module is further configured to determine a second routing calculation algorithm based on a third time, the second routing calculation algorithm including second validity time information and a second network topology constraint, the second validity time information indicating the validity time of the second routing calculation algorithm, the second validity time information and the second network topology constraint being used to determine a network topology corresponding to the second routing calculation algorithm, the third time being before the validity time of the second routing calculation algorithm, the validity time of the first routing calculation algorithm being different from the validity time of the second routing calculation algorithm; and determining a second network topology to be used during the validity time of the second routing calculation algorithm based on the second validity time information and the second network topology constraint, wherein the second routing calculation algorithm and the second network topology are determined before the validity time of the second routing calculation algorithm.

[0028] In a possible implementation, the first validity time information further includes a change period of the validity time of the first routing calculation algorithm, and the change period of the validity time of the first routing calculation algorithm is determined based on the first validity time information and the second validity time information.

[0029] In a possible implementation, the first routing calculation algorithm is a flex-algo or a multi-topology algorithm.

[0030] In one possible implementation, the first routing calculation algorithm is flex-algo; the transceiver module is used to receive an ISIS link state data unit LSP message for announcing the first routing calculation algorithm, the first routing calculation algorithm is carried in the FAD sub-TLV field of the ISIS LSP message, and the first validity time information is carried in the validity time sub-TLV field of the FAD sub-TLV.

[0031] In one possible implementation, the first routing calculation algorithm is flex-algo; the transceiver module is used to receive an OSPF LSA message for announcing the first routing calculation algorithm, the first routing calculation algorithm is carried in the FAD TLV field of the OSPF LSA message, and the first valid time information is carried in the valid time sub-TLV field of the FAD TLV.

[0032] In one possible implementation, the first routing calculation algorithm is flex-algo; the transceiver module is used to receive a BGP update message for announcing the first routing calculation algorithm, the first routing calculation algorithm is carried in the FAD TLV field of the BGP update message, and the first valid time information is carried in the valid time sub-TLV field of the FAD TLV.

[0033] In one possible implementation, the first routing calculation algorithm is a multi-topology algorithm; the transceiver module is used to receive an ISIS LSP message for announcing the first routing calculation algorithm, the first routing calculation algorithm is carried in a time-varying MT information sub-TLV field of the ISIS LSP message, and the first effective time information is carried in an effective time sub-TLV field of the time-varying MT information sub-TLV.

[0034] In one possible implementation, the first routing calculation algorithm is a multi-topology algorithm; the transceiver module is used to receive an Open Shortest Path First (OSPF) link state advertisement (LSA) message used to announce the first routing calculation algorithm, the first routing calculation algorithm is carried in a time-varying MT information TLV field of the OSPF LSA message, and the first effective time information is carried in an effective time sub-TLV field of the time-varying MT information TLV.

[0035] In one possible implementation, the first routing calculation algorithm is a multi-topology algorithm; the transceiver module is used to receive a BGP update message for announcing the first routing calculation algorithm, the first routing calculation algorithm is carried in a time-varying MT information TLV field of the BGP update message, and the first effective time information is carried in an effective time sub-TLV field of the time-varying MT information TLV.

[0036] In a third aspect, a network device is provided, comprising: a processor, the processor being coupled to a memory, the memory storing at least one program instruction or code, the at least one program instruction or code being loaded and executed by the processor, so that the network device implements the method for determining the network topology as described in the first aspect or any one of the first aspects above.

[0037] Optionally, there are one or more processors and one or more memories.

[0038] Optionally, the memory may be integrated with the processor, or the memory may be provided separately from the processor.

[0039] In the specific implementation process, the memory can be a non-transitory memory, such as a read-only memory (ROM), which can be integrated on the same chip as the processor or be set on different chips. This application does not limit the type of memory and the setting method of the memory and the processor.

[0040] In a fourth aspect, a computer-readable storage medium is provided, wherein the storage medium stores at least one instruction, and the instruction is loaded and executed by a processor to enable a computer to implement the methods in the above aspects.

[0041] In a fifth aspect, a computer program (product) is provided, which includes: computer program code, which, when executed by a computer, enables the computer to execute the methods in the above aspects.

[0042] In a sixth aspect, a chip is provided, comprising a processor for calling and executing instructions stored in a memory from the memory, so that a communication device equipped with the chip executes the methods in the above aspects.

[0043] In the seventh aspect, another chip is provided, comprising: an input interface, an output interface, a processor and a memory, wherein the input interface, the output interface, the processor and the memory are connected through an internal connection path, and the processor is used to execute the code in the memory. When the code is executed, the processor is used to execute the methods in the above aspects.

[0044] It should be understood that the beneficial effects achieved by the technical solutions of the second to seventh aspects of this application and the corresponding possible implementation methods can be found in the above-mentioned technical effects of the first aspect and its corresponding possible implementation methods, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 is a schematic diagram of a change in resource utilization of a cell base station provided in an embodiment of the present application;

[0046] FIG2 is a schematic diagram of an implementation environment of a method for determining a network topology provided in an embodiment of the present application;

[0047] FIG3 is a flow chart of a method for determining a network topology provided in an embodiment of the present application;

[0048] FIG4 is a schematic diagram of the format of a FAD sub-TLV field provided in an embodiment of the present application;

[0049] FIG5 is a schematic diagram of the format of a FAD TLV field provided in an embodiment of the present application;

[0050] FIG6 is a schematic diagram of the format of a time-varying MT information sub-TLV field provided in an embodiment of the present application;

[0051] FIG7 is a schematic diagram of the format of a time-varying MT information TLV field provided in an embodiment of the present application;

[0052] FIG8 is a schematic diagram of the format of a valid time sub-TLV field provided in an embodiment of the present application;

[0053] FIG9 is a schematic diagram of the format of another valid time sub-TLV field provided in an embodiment of the present application;

[0054] FIG10 is a schematic diagram of the format of another valid time sub-TLV field provided in an embodiment of the present application;

[0055] FIG11 is a schematic diagram of the format of another valid time sub-TLV field provided in an embodiment of the present application;

[0056] FIG12 is a schematic diagram of a process of switching network topology provided in an embodiment of the present application;

[0057] FIG13 is a schematic diagram of another process of switching network topology provided in an embodiment of the present application;

[0058] FIG14 is a schematic diagram of another process of switching network topology provided in an embodiment of the present application;

[0059] FIG15 is a schematic diagram of the structure of a device for determining a network topology provided in an embodiment of the present application;

[0060] FIG16 is a schematic diagram of the structure of a network device provided in an embodiment of the present application;

[0061] FIG17 is a schematic diagram of the structure of another network device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0062] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0063] In the embodiments of the present application, a network whose network topology changes over time is referred to as a time-varying network. For example, for a network with a tidal effect on network traffic, since there are obvious differences in traffic in different time periods, a network topology with a large network connection scale can be used to forward messages during a time period with large traffic. When a time period with small traffic arrives, some network connections in the network topology are closed, and a network topology with a small network connection scale is used to forward messages, so as to ensure that there is no network congestion during a time period with large traffic and to avoid waste of resources during a time period with small traffic. In this scenario, the change in network topology is caused by a change in the network connection state. The network connection state refers to the network connection state that can affect the forwarding path of the message. The network connection state includes but is not limited to the state of the link, the state of the network node, or the state of the route.

[0064] Taking a mobile network as an example, referring to the schematic diagram of the resource utilization changes of a cell base station over a day shown in Figure 1, the resource utilization of the cell base station shows a clear tidal effect throughout the day. Resource utilization is proportional to the amount of traffic. The resource utilization between 0:00 and 7:00 is low, i.e., the traffic is low, which can be called a low-traffic time period. The resource utilization between 7:00 and 24:00 is high, i.e., the traffic is high, which can be called a high-traffic time period. Therefore, a network topology with a small network connection scale can be used between 0:00 and 7:00, and a network topology with a large network connection scale can be used between 7:00 and 24:00. That is, in a network where network traffic has a tidal effect, taking the traffic variation time period including a high-traffic time period and a low-traffic time period as an example, two network topologies can be formed: a first network topology for the high-traffic time period and a second network topology for the low-traffic time period. During the message forwarding process, switching between the two network topologies is performed based on time, thereby forming a time-varying network.

[0065] For example, in satellite networks, due to the cyclical and predictable nature of satellite constellation operations, satellite networks can be divided into multiple discrete network topologies along the time axis. The network topology within each time slice can be considered fixed and unchanging. In other words, in satellite networks, the network topology changes regularly and predictably, thus forming a time-varying network. For another example, in energy-prioritized networks, network connections are adaptively closed or opened based on real-time changes in network traffic. For example, network devices may be shut down when idle to reduce energy waste caused by idle devices. Therefore, in energy-prioritized networks, the network topology will also change in response to changes in the energy consumption of network devices, which are also predictable, thus forming a time-varying network.

[0066] The embodiments of the present application only illustrate time-varying networks using tidal networks, satellite networks, and energy-prioritized networks as examples. For other time-varying networks with predictable changes in network topology, the embodiments of the present application will no longer provide examples one by one. In the scenario of time-varying networks, how to control network traffic to switch to different network topologies in different time periods is an urgent problem to be solved, and the transmission of network traffic in different network topologies is based on routing information. Therefore, how the routing calculation algorithm switches to use different network topologies for routing calculation in different time periods is an urgent problem to be solved.

[0067] In the related art, taking the routing calculation algorithm as flex-algo as an example, flex-algo can allow network devices to calculate routes based on specific network topology constraints and routing constraints, so that different flex-algos can meet the needs of different business scenarios, such as high-bandwidth services or low-latency services, and thus flex-algo can more simply and flexibly implement the network's traffic engineering (TE) capabilities. Among them, before performing routing calculation based on routing constraints, it is necessary to first determine the network topology based on the network topology constraints, so as to perform routing calculation based on routing constraints in the determined network topology and obtain routing information corresponding to the determined network topology. Among them, the network topology that changes over time refers to the change of the physical network topology, and the network topology determined in the physical network topology based on the routing calculation algorithm is the logical network topology.

[0068] Because flex-algos in related technologies all calculate routes simultaneously, if the network topology changes, network devices must re-determine the network topology corresponding to all flex-algos and perform route calculations based on the changed network topology, resulting in high processing overhead for network devices. Furthermore, during this process, since the physical network topology has changed while network traffic is still transmitted within the pre-changed network topology, packet loss can occur, impacting service transmission performance.

[0069] In other words, the flex-algo in related technologies only implements network topology constraints and routing constraints based on the spatial dimension. This means that network traffic with the same traffic characteristics but different arrival times will be directed to be forwarded using routing information calculated based on the same flex-algo. This means that network traffic arriving when the network topology changes must wait for the route to be recalculated based on the same flex-algo before it can be switched to the changed network topology for forwarding. Therefore, the methods in related technologies are inefficient in switching network topologies.

[0070] The present application provides a method for determining network topology by adding effective time information to a routing calculation algorithm, thereby providing the routing calculation algorithm with an effective time constraint in the time dimension. This allows routing calculations to be performed based on different routing calculation algorithms according to time. Because different routing calculation algorithms use different network topologies for routing, switching between different routing calculation algorithms based on time enables flexible switching of network topologies. This method can be applied to any network system, for example, the aforementioned time-varying network, to achieve flexible switching of network topologies for different time periods based on the time-varying properties of the time-varying network.

[0071] For example, see Figure 2, which is a diagram of an implementation environment for a method for determining a network topology provided by an embodiment of the present application. As shown in Figure 2, the implementation environment includes multiple network devices, any of which can be connected to another network device via a link, and the link connection relationship between each network device can be configured according to network requirements. The network device can be a switch or router, etc., and each network device corresponds to a node in the network. Among them, changes in the state of the link and the state of the node will both cause changes in the network topology. For example, if the state of network device 2 changes from valid to invalid, the states of link 1 and link 3 also change from valid to invalid. The changed network topology lacks link 1 and link 3 compared to the network topology before the change. For example, when the network device is powered off or turned off, the state of the network device is invalid; when the network device is powered on or turned on, the state of the network device is valid. When the link is closed or disconnected, the state of the link is invalid; when the link is open or connected, the state of the link is valid.

[0072] In an embodiment of the present application, the network devices in the implementation environment shown in Figure 2 may also include more or less, that is, the embodiment of the present application does not limit the number of network devices. Among them, the network devices mentioned in the embodiment of the present application, in addition to being network devices such as switches and routers, can also be part of the components on the network device, such as a single board or line card on the network device, or a functional module on the network device, or a chip for implementing the method provided in the embodiment of the present application, which is not specifically limited in the embodiment of the present application. When the network device is a chip, the transceiver module used to implement the method can be, for example, an interface circuit of the chip, and the processing module can be a processing circuit with processing functions in the chip. The connection method between network devices includes but is not limited to direct connection via Ethernet cable or optical cable.

[0073] Referring to Figure 3 , Figure 3 is a flowchart of a method for determining a network topology provided in an embodiment of the present application. This method for determining a network topology can be applied in the implementation environment shown in Figure 2 , for example, by any network device in the implementation environment shown in Figure 2 . As shown in Figure 3 , this method for determining a network topology includes, but is not limited to, the following steps 301 and 302 .

[0074] Step 301: Determine a first routing calculation algorithm based on a first time. The first routing calculation algorithm includes first effective time information and a first network topology constraint. The first effective time information includes an effective time of the first routing calculation algorithm. The first effective time information and the first network topology constraint are used to determine a network topology corresponding to the first routing calculation algorithm. The first time is before the effective time of the first routing calculation algorithm.

[0075] In an embodiment of the present application, in addition to the first network topology constraint, the first route calculation algorithm also includes first validity period information. The first validity period information is used to constrain the validity period of the first route calculation algorithm, so that during the validity period of the first route calculation algorithm, routing information calculated based on the first route calculation algorithm is used to forward packets. This allows the first route calculation algorithm to be determined at a first time before the validity period of the first route calculation algorithm, eliminating the need to determine all route calculation algorithms at the same time.

[0076] Optionally, the present embodiment of the application does not limit the content of the first effective time information, as long as it can constrain the effective time of the first route calculation algorithm. For example, the first effective time information includes the effective time, which is the time when the first route calculation algorithm begins to take effect; or the first effective time information includes the effective time and the expiration time, which is the time when the first route calculation algorithm begins to fail, and the time period between the effective time and the expiration time is the effective time period from the time the first route calculation algorithm takes effect to the time it fails; or the first effective time information includes the effective time and the duration period, and the duration period starting from the effective time is the effective time period from the time the first route calculation algorithm takes effect to the time it fails.

[0077] In one possible implementation, when the first validity period information includes a validity period, the validity period of the first routing calculation algorithm corresponds to the validity period of the first network topology. That is, the validity period of the first routing calculation algorithm can be determined based on the validity period of the first network topology. For scenarios where the network connection status changes, the network topology before and after the change in network connection status differs, i.e., the network topologies valid at different times differ, meaning that any network topology is valid within the corresponding validity period. Therefore, the validity period of the first routing calculation algorithm corresponds to the validity period of the first network topology, enabling network topology switching by switching the routing calculation algorithm, thereby avoiding packet loss caused by network topology changes.

[0078] The validity period of the first routing calculation algorithm corresponds to the validity period of the first network topology, and the validity period of the first routing calculation algorithm is the same as the validity period of the first network topology. For example, if the network connection included in the first network topology becomes effective at the first validity period, the validity period of the first network topology is the first validity period, and the first routing calculation algorithm also becomes effective at the first validity period, and the first network topology has been determined to be obtained before the first validity period. Therefore, when the first validity period is reached, the network device can directly switch the current network topology to the first network topology and ensure that the network connection status of the first network topology is valid at the first validity period.

[0079] Similarly, when the first validity period information includes a validity period and an expiration period, the validity period of the first routing calculation algorithm corresponds to the validity period of the first network topology, and the expiration period of the first routing calculation algorithm corresponds to the expiration period of the first network topology. When the first validity period information includes a validity period and a duration period, the validity period of the first routing calculation algorithm corresponds to the validity period of the first network topology, and the duration period of the first routing calculation algorithm corresponds to the duration period of the first network topology. This ensures that the validity period information of the routing calculation algorithm corresponds to the time information of changes in the network connection status of the network topology.

[0080] In one possible implementation, for a time-varying network with periodic changes in network topology, the first validity period information also includes a variation period of the validity period of the first routing calculation algorithm, and the variation period indicates multiple periodic validity periods of the first routing calculation algorithm. For example, if the validity period of the first routing calculation algorithm is 10:00, and the variation period of the validity period of the first routing calculation algorithm is one day, then the first routing calculation algorithm will take effect at 10:00 every day. For another example, if the validity period of the first routing calculation algorithm is 10:00 and the expiration time is 22:00, and the variation period of the validity period of the first routing calculation algorithm is one day, then the first routing calculation algorithm will take effect at 10:00 every day and will become invalid at 22:00 every day.

[0081] In an embodiment of the present application, the period of change of the effective time of the first routing calculation algorithm corresponds to the period of change of the effective time of the first network topology. By carrying the period of change of the effective time in the first effective time information, the first routing calculation algorithm can be periodically effective, thereby improving the flexibility of the time constraint of the first routing calculation algorithm. In addition, the period of change of the effective time of the first routing calculation algorithm corresponds to the period of change of the effective time of the first network topology, so that by periodically switching the routing calculation algorithm, it is possible to achieve periodic switching of the network topology, thereby avoiding packet loss caused by using the first routing calculation algorithm outside the effective time of the first network topology.

[0082] For time-varying networks whose network topology does not have obvious periodic changes but changes are predictable, this method can simultaneously define two routing calculation algorithms. For example, when it is predicted that the network topology will change between a first target time and a second target time, a first routing calculation algorithm and a second routing calculation algorithm can be defined. The first routing calculation algorithm can have an effective time of the first target time and an expiration time of the second target time. The second routing calculation algorithm can have an effective time of the second target time and an expiration time of the third target time. The third target time can be any time after the second target time. Alternatively, the effective time of the first routing calculation algorithm can be different from the first target time, and the expiration time can be different from the second target time. That is, the effective time and expiration time of the first routing calculation algorithm can be different from the time when the physical network topology changes. For example, the effective time and expiration time of the first routing calculation algorithm can be flexibly set to different fixed values ​​based on the actual changes in the network topology of the time-varying network.

[0083] In one possible implementation, the method further includes determining a second route calculation algorithm based on a third time, the second route calculation algorithm including second validity period information and a second network topology constraint, the second validity period information indicating the validity period of the second route calculation algorithm, the second validity period information and the second network topology constraint being used to determine a network topology corresponding to the second route calculation algorithm, and the third time being before the validity period of the second route calculation algorithm. Thus, different route calculation algorithms corresponding to different validity periods can be defined, making the application of the route calculation method more flexible.

[0084] The validity period of the first route calculation algorithm is different from the validity period of the second route calculation algorithm. The expiration period of the first route calculation algorithm may be the same as or different from the validity period of the second route calculation algorithm. When the expiration period of the first route calculation algorithm is later than the validity period of the second route calculation algorithm, the validity period of the first route calculation algorithm and the validity period of the second route calculation algorithm overlap. When the expiration period of the first route calculation algorithm and the validity period of the second route calculation algorithm are the same, the validity period of the first route calculation algorithm and the validity period of the second route calculation algorithm are continuous.

[0085] In an embodiment of the present application, the third time may be the same as or different from the first time. When the third time is the same as the first time, the first routing calculation algorithm and the second routing calculation algorithm may be determined simultaneously at the same time. Since the network topology does not have obvious periodic changes in this case, if the first effective time information also includes the change period of the effective time of the first routing calculation algorithm, the change period of the effective time of the first routing calculation algorithm may be determined based on the first effective time information and the second effective time information. In the case of defining multiple routing calculation algorithms with different effective times, the change period of the effective time of the routing calculation algorithm may be determined based on the effective time information of each routing calculation algorithm, thereby enabling the multiple routing calculation algorithms to be used periodically and cyclically.

[0086] For example, the period of change in the effective time of the first route calculation algorithm is the time period between the effective time in the first effective time information and the expiration time in the second effective time information; or, the period of change in the effective time of the first route calculation algorithm is the sum of the effective time period indicated by the first effective time information and the effective time period indicated by the second effective time information. Optionally, the content of the second effective time information can refer to the content of the first effective time information and is not further described here. Exemplarily, the second effective time information also includes the period of change in the effective time of the second route calculation algorithm, and the period of change in the effective time of the second route calculation algorithm can be the same as the period of change in the effective time of the first route calculation algorithm.

[0087] Before determining the first route calculation algorithm based on the first time, it is necessary to first obtain the first route calculation algorithm so that the first route calculation algorithm can be directly determined from multiple route calculation algorithms at the first time. Optionally, the first route calculation algorithm can be obtained by defining the first route calculation algorithm based on the time information of the change of the network connection status, or by receiving a message for announcing the first route calculation algorithm to obtain the first route calculation algorithm.

[0088] In one possible implementation, the algorithm type of the first routing calculation algorithm or the second routing calculation algorithm can be any routing calculation algorithm that performs routing calculation based on network topology constraints, such as a flex-algo or a multi-topology algorithm. For flex-algo, the network topology constraint can refer to a constraint condition that a link must satisfy. For example, the first network topology constraint can include a link color constraint, and the link color constraint is used to constrain the color of the links included in the first network topology. Different colors are used to distinguish different valid times, and the color of the links included in the first network topology complies with the link color constraint.

[0089] The link color constraint constrains the colors of the links included in the first network topology in two ways, including but not limited to the following: the first is to indicate the colors of the links included in the first network topology through the link color constraint. For example, if the link color constraint indicates yellow, the color of the links included in the first network topology is yellow. The second is to indicate the colors of the links excluded from the first network topology through the link color constraint. For example, if the link color constraint indicates yellow, the color of the links included in the first network topology does not include yellow. By coloring the links differently for different validity periods, the link color constraint can determine the first network topology corresponding to the specified color, and the first network topology is valid during the validity period indicated by the specified color.

[0090] As for the multi-topology algorithm, since the multi-topology algorithm refers to running multiple independent network topologies within an ISIS autonomous system, different routing information for different network topologies can be calculated based on shortest path first (SPF) through the multiple independent network topologies, thereby achieving mutual shielding between the multiple independent network topologies. Therefore, when the first routing calculation algorithm is the multi-topology algorithm, the first network topology constraint can refer to the link identifiers of multiple links, and the links included in the first network topology belong to the links corresponding to the link identifiers in the first network topology constraint.

[0091] When the first route calculation algorithm is flex-algo, before determining the first route calculation algorithm based on the first time, an ISIS LSP message for announcing the first route calculation algorithm may also be received, the first route calculation algorithm being carried in the FAD sub-TLV field of the ISIS LSP message, and the first validity time information being carried in the validity time sub-TLV field of the FAD sub-TLV; or an OSPF LSA message for announcing the first route calculation algorithm being received, the first route calculation algorithm being carried in the FAD TLV field of the OSPF LSA message, and the first validity time information being carried in the validity time sub-TLV field of the FAD TLV; or a BGP update message for announcing the first route calculation algorithm being received, the first route calculation algorithm being carried in the FAD TLV field of the BGP update message, and the first validity time information being carried in the validity time sub-TLV field of the FAD TLV. Thus, multiple methods for announcing flexible algorithms are provided, and methods for carrying the validity time information of flexible algorithms are also provided, respectively, to provide a guarantee for the implementation of the method.

[0092] Exemplarily, the FAD sub-TLV field carrying the first flexible algorithm can be as shown in Figure 4. As shown in Figure 4, the FAD sub-TLV field includes a type field, a length field, a flexible algorithm (Flex-Algo) field, a metric type (Metric-Type) field, a calculation type (Calc-Type) field, a priority (Priority) field, a valid time sub-TLV field, and a sub-TLVs field. The format definition of the FAD sub-TLV field can refer to the relevant description in the information request (RFC) 9350. Optionally, the FAD sub-TLV field can be carried in the routing capability (Router CAPABILITY) TLV-242 field of the ISIS LSP message. For detailed description, please refer to the relevant description in RFC7981.

[0093] The type field is used to uniquely identify the FAD sub-TLV. For example, the value of the type field is 26. The length field indicates the total length of the FAD sub-TLV field after removing the type field and the length field. For example, the unit of the length field is bytes. The Flex-Algo field indicates the identification (ID) of the first flexible algorithm. The value of the Flex-Algo field is a value from 128 to 255. The Metric-Type field indicates the path calculation constraint of the first flexible algorithm. The path calculation constraint is the metric type used when calculating the route. For example, when the value of the Metric-Type field is 1, it indicates that the route is calculated based on the minimum unidirectional link delay. When the value of the Metric-Type field is 2, it indicates that the route is calculated based on the TE metric. The Calc-Type field indicates the calculation method of the first flexible algorithm, for example, the SPF calculation method. The Priority field indicates the priority announced by the first flexible algorithm. The value of the Priority field is a value from 0 to 255. The validity period sub-TLV field is used to carry the first validity period information. The sub-TLVs field is of variable length and is used to carry other constraints of the first flexible algorithm.

[0094] Exemplarily, the FAD TLV field carrying the first flexible algorithm can be as shown in Figure 5. The meaning of the various fields shown in Figure 5 can be found in the relevant introduction to the various fields in Figure 4, and will not be repeated here. Optionally, the FAD TLV field shown in Figure 5 can be carried in the Router Information (RI) LSA field of the OSPF LSA message. For detailed introduction, please refer to the relevant description in RFC7770; or, the FAD TLV field shown in Figure 5 can be carried in the BGP-LS routing attribute corresponding to the node (Node) network layer reachability information (NLRI) of the BGP update message. For detailed introduction, please refer to the relevant description in RFC9351.

[0095] When the first route calculation algorithm is a multi-topology algorithm, before determining the first route calculation algorithm based on the first time, an ISIS LSP message for announcing the first route calculation algorithm may also be received, where the first route calculation algorithm is carried in the Time-Varying MT Information sub-TLV field of the ISIS LSP message, and the first validity time information is carried in the Validity Time sub-TLV field of the Time-Varying MT Information sub-TLV; or an OSPF LSA message for announcing the first route calculation algorithm is received, where the first route calculation algorithm is carried in the Time-Varying MT Information TLV field of the OSPF LSA message, and the first validity time information is carried in the Validity Time sub-TLV field of the Time-Varying MT Information TLV; or a BGP update message for announcing the first route calculation algorithm is received, where the first route calculation algorithm is carried in the Time-Varying MT Information TLV field of the BGP update message, and the first validity time information is carried in the Validity Time sub-TLV field of the Time-Varying MT Information TLV. Multiple methods for announcing the multi-topology algorithm are provided, and methods for carrying the validity time information of the multi-topology algorithm are also provided, respectively, to ensure the implementation of the method.

[0096] Exemplarily, the time-varying MT information sub-TLV field carrying the first flexible algorithm can be shown in Figure 6. The time-varying MT information sub-TLV field includes a type field, a length field, a reserved field, an MT ID field, and a valid time sub-TLV field. The type field is used to uniquely identify the time-varying MT information sub-TLV; the length field indicates the total length of the time-varying MT information sub-TLV field after removing the type field and the length field. For example, the unit of the length field is bytes; the reserved field is an unallocated field; the MT ID field indicates the ID of the first multi-topology algorithm, which is 12 bits long. For detailed introduction, please refer to the relevant description in RFC5120; the valid time sub-TLV field is used to carry the first valid time information.

[0097] Optionally, in addition to the first multi-topology algorithm, the time-varying MT information sub-TLV field of the ISIS LSP message may also include multiple multi-topology algorithms such as the second multi-topology algorithm and the third multi-topology algorithm. In this case, as shown in Figure 6, the time-varying MT information sub-TLV field may carry multiple MT ID fields corresponding to multiple multi-topology algorithms, for example, the MT ID1 field and the MT ID2 field, each MT ID field including a corresponding valid time sub-TLV field. Optionally, the time-varying MT information sub-TLV field may be carried in the Router CAPABILITY TLV-242 field of the ISIS LSP message. For detailed description, please refer to the relevant description in RFC7981. In addition, a new time-varying MT information TLV field may be defined in the ISIS LSP message to carry the time-varying MT information sub-TLV field.

[0098] Exemplarily, the time-varying MT information TLV field carrying the first flexible algorithm may be as shown in FIG7 . The meaning of each field shown in FIG7 can be found in the relevant introduction to each field in FIG6 , and will not be repeated here. Optionally, the time-varying MT information TLV field shown in FIG7 can be carried in the RI LSA field of the OSPF LSA message. For detailed description, please refer to the relevant description in RFC7770. In addition, a new LSA may be defined in the OSPF LSA message to carry the time-varying MT information TLV field; or, the time-varying MT information TLV field shown in FIG7 may be carried in the BGP-LS route attribute corresponding to the Node NLRI of the BGP update message. For detailed description, please refer to the relevant description in RFC9351. In addition, a new NLRI type may be defined in the BGP update message to carry the time-varying MT information TLV field, or the time-varying MT information TLV field may be carried in the local node descriptor (Local Node Descriptors) field of the existing Node NLRI.

[0099] Since the validity time information provided in the embodiments of the present application may include different content, the format diagrams of the validity time sub-TLV field carrying the validity time information are also different. Optionally, the embodiments of the present application only use the format diagrams of the validity time sub-TLV field shown in Figures 8-11 as an example for illustration.

[0100] In the validity period sub-TLV field shown in Figure 8 , the type field is 1 or 2 bytes long and is used to uniquely identify the structure of the first route calculation algorithm; the length field is 1 or 2 bytes long and is used to indicate the length of the field structure of the validity period information, excluding the length field and the type field; the enable time field is 4 bytes long and is used to indicate the first time the first route calculation algorithm is enabled; and the disable time field is 4 bytes long and is used to indicate the first time the first route calculation algorithm is disabled. Compared to Figure 8 , the validity period sub-TLV field shown in Figure 9 adds a period field. The period field is 4 bytes long and is used to indicate the changing period of the validity period of the first route calculation algorithm. For an introduction to the other fields, please refer to the relevant content in Figure 8 and will not be repeated here.

[0101] In an embodiment of the present application, the valid time sub-TLV field can carry multiple valid time information through multiple change time units. For example, a change time unit includes a corresponding change time information index (index), control flags (flags), and a triplet of valid time, expiration time and period. Therefore, the valid time sub-TLV can also include information such as the number of change time units.

[0102] For example, referring to the valid time sub-TLV field shown in FIG10 , FIG10 adds an initial time field, a number field, and a reserved field compared to FIG8 . Among them, the initial time field is an 8-byte timestamp in seconds. For example, the value of the initial time field is the number of seconds that have passed since January 1, 1970, excluding leap seconds; the number field is 1 byte long and is used to indicate the number of change time information in the field structure of the time constraint; the unit field is 1 byte long and is used to indicate the time unit of the variable time information for subsequent expansion. For example, the meaning of the unit field can be as shown in Table 1. Taking the unit value (value) of 0 as an example, it indicates that the unit of the valid time, expiration time, and period in the change time unit is microseconds. The case where the unit value is 9-255 has not yet been assigned.

[0103] Table 1

[0104] Referring to the valid time sub-TLV field shown in Figure 11, compared to Figure 9, Figure 11 adds the initial time field, number field, and reserved field. Compared to Figure 10, Figure 11 adds the index field, flags field, and period field. For each change time unit in the valid time sub-TLV, the index field is the first field of the change time unit. This index field is the index of the change time unit and uniquely identifies the change time unit that carries valid time information. The flags field is a control flag bit, and each bit in the flags field represents a corresponding control operation. For example, the least significant bit of the flags field is used as a deletion control bit. When the least significant bit of the flags field is 1, it indicates that the valid time information in the change time unit is deleted. The index field and flags field can be used to implement operations such as deleting and modifying the published valid time information of the first routing calculation algorithm.

[0105] Step 302: Determine a first network topology to be used during the effective time of a first routing calculation algorithm based on first effective time information and a first network topology constraint. The first routing calculation algorithm and the first network topology are determined before the effective time of the first routing calculation algorithm.

[0106] In the embodiment of the present application, the first effective time information and the first network topology constraint are used to determine the network topology corresponding to the first routing calculation algorithm. Therefore, before the effective time of the first routing calculation algorithm, by determining the first effective time information and the first network topology constraint, the first network topology used during the effective time of the first routing calculation algorithm can be determined in advance. The first network topology can be generated at the first time, or it can be generated before the first time, and the pre-determined first network topology can be directly selected at the first time. In short, the first network topology is determined before the effective time of the first routing calculation algorithm.

[0107] Optionally, when the first network topology is generated at the first time, the method for generating the first network topology based on the first effective time information and the first network topology constraint can be to determine the physical network topology that is effective at the effective time of the first routing calculation algorithm based on the first effective time information and the time change information of the network connection state, and then determine the first network topology that satisfies the first network topology constraint in the physical network topology. The difference between the first time and the effective time of the first routing calculation algorithm is not limited in this embodiment of the present application. The smaller the difference between the first time and the effective time of the first routing calculation algorithm, the closer the first network topology generated at the first time is to the actual physical network topology, thereby avoiding changes in the physical network topology between the first time and the effective time of the first routing calculation algorithm.

[0108] When the first network topology constraint includes a link color constraint, since different colors are used to distinguish different validity times, the first network topology generated based on the first validity time information and the first network topology constraint can be determined by directly determining the first network topology that complies with the link color constraint based on the color attributes included in the link. For example, if a link includes a yellow attribute, and yellow indicates a first validity time period, indicating that the link is valid during the first validity time period, then the network topology composed of links with yellow attributes is a network topology that is valid during the first validity time period. In other words, by coloring links differently for different validity times, the link color constraint can be used to determine the first network topology corresponding to a specified color, and this first network topology is valid during the validity time indicated by the specified color.

[0109] Similar to the first route calculation algorithm, when the second route calculation algorithm is also determined, the second network topology used at the effective time of the second route calculation algorithm can be determined based on the second effective time information and the second network topology constraint, and the second route calculation algorithm and the second network topology are determined before the effective time of the second route calculation algorithm.

[0110] In summary, by adding the first effective time information to the first routing calculation algorithm, the first routing calculation algorithm takes effect at the effective time of the first routing calculation algorithm, and then by determining in advance before the effective time of the first routing calculation algorithm the first network topology used at the effective time of the first routing calculation algorithm, the first network topology determined in advance can be directly used to calculate the route at the effective time of the first routing calculation algorithm, thereby improving the efficiency of determining the first network topology, and thereby improving the efficiency of calculating the routing information of the first network topology based on the routing calculation algorithm.

[0111] In an embodiment of the present application, after determining the first network topology to be used at the first effective time based on the first effective time information and the first network topology constraint, the method can also calculate the first routing information of the first network topology based on the first routing calculation algorithm at a second time, where the second time is before the effective time of the first routing calculation algorithm, the second time is the same as the first time, or is after the first time. The difference between the second time and the effective time of the first routing calculation algorithm is less than a difference threshold, and the difference threshold can be flexibly adjusted according to the application scenario. For example, the difference threshold can be a smaller value so that the second time is closer to the effective time of the first routing calculation algorithm. Since the first routing calculation algorithm calculates the route in the first network topology, the first routing information is used to forward messages in the first network topology.

[0112] Therefore, the first routing information of the first network topology can be calculated in advance based on the routing calculation algorithm before the effective time of the first routing calculation algorithm, so that the first routing information calculated in advance can be directly used to forward messages during the effective time of the first routing calculation algorithm, and there is no need to calculate the first routing information at the effective time of the first routing calculation algorithm, thereby improving the efficiency of message forwarding based on the first routing information and avoiding packet loss in the process of calculating the first routing information.

[0113] In an embodiment of the present application, after calculating first routing information for a first network topology based on a first routing calculation algorithm, packets can be forwarded within the first network topology based on the calculated first routing information. For example, the network device determines whether the network traffic arrives within the valid time period of the first routing calculation algorithm and forwards the network traffic based on the first routing information, thereby achieving the effect of directing the network traffic to the first network topology for forwarding.

[0114] The following examples illustrate the methods provided in the embodiments of the present application based on different time-varying networks. FIG. 12 is a flowchart illustrating network topology switching for a time-varying network with periodic topology changes, such as a tidal network. FIG. 13 and FIG. 14 are flowcharts illustrating network topology switching for a time-varying network with no apparent periodic topology changes, such as a satellite network or an energy-prioritized network.

[0115] Referring to Figure 12, taking the tidal network and flexible algorithm as an example, for the high-traffic time period and low-traffic time period of the tidal network, two flexible algorithms, the first flexible algorithm and the second flexible algorithm, can be defined, and then the network topology switching can be achieved through the following steps 1-6.

[0116] 1. Link coloring and notification of link changes. Any network device in the tidal network assigns different color attributes to the links directly connected to any network device based on the change pattern of link opening and closing. Different valid time periods of the link are marked with different colors. This process is called link coloring. For example, a link that is open in both high-traffic and low-traffic time periods is assigned a green attribute, and a link that is only open in low-traffic time periods is assigned a yellow attribute. In Figure 12, the low-traffic time period is (t0-t1), and the high-traffic time period is (t1-t2). The straight line represents the green attribute of the link, and the dotted line represents the yellow attribute of the link.

[0117] Each network device in the tidal network notifies each other of the coloring attribute information of the links directly connected to each network device. This process is called notifying link changes. In addition to notifying each other of the coloring attribute information of the links directly connected to each network device, each network device also notifies each other of other link attribute information such as interruptions and metric values ​​of the links directly connected to each network device. Furthermore, each network device in the tidal network can obtain the attribute information of each link in the tidal network, thereby enabling the network topology that is effective during low-traffic time periods and the network topology that is effective during high-traffic time periods to be determined in advance.

[0118] 2. Define flexible algorithms. A first flexible algorithm and a second flexible algorithm can be defined on any one or more network devices in a tidal network. The first effective time information included in the first flexible algorithm indicates a low-traffic time period, and the second effective time information included in the second flexible algorithm indicates a high-traffic time period. That is, the effective time period and change period of the flexible algorithm are the same as the effective time period and change period of the network topology corresponding to the flexible algorithm. Optionally, the effective time, expiration time, and change period of the flexible algorithm can be input externally, for example, they can be sent to the network device through a controller, or obtained through manual configuration.

[0119] Optionally, the first network topology constraint included in the first flexible algorithm is a link color constraint. For example, the first network topology constraint indicates that only links with green attributes are used to determine the network topology; the second network topology constraint included in the second flexible algorithm is also a link color constraint. For example, the second network topology constraint indicates that links with green attributes and yellow attributes are used to determine the network topology. In Figure 12, the flexible algorithm ID of the defined first flexible algorithm is 128, and the first effective time information of the first flexible algorithm is (t0-t1, T); the flexible algorithm ID of the defined second flexible algorithm is 129, and the second effective time information of the second flexible algorithm is (t1-t2, T), where T is the change period. In an embodiment of the present application, the first flexible algorithm or the second flexible algorithm may further include other constraints, such as metric type, metric value range, and other constraints, and the network topology is determined by the other constraints and the first effective time information.

[0120] 3. Announce the flexible algorithm. The network device used to define the flexible algorithm can announce the flexible algorithm of the time-varying network to other network devices, and announce the segment ID locator (SID locator) or Internet Protocol (IP) prefix corresponding to the flexible algorithm together with the flexible algorithm. Optionally, the flexible algorithm is carried in the FAD TLV of the message for announcement. In Figure 12, the FAD TLV includes the flexible algorithm ID: 128, the valid time information: (t0-t1, T), the flexible algorithm ID: 129, and the valid time information is (t1-t2, T). Among them, the SID of algorithm (algo): 128 is 10065, and the SID of algo: 129 is 20065.

[0121] 4. Generate a logical topology. By executing the method provided in the embodiments of the present application, each network device in the tidal network can generate a first network topology for use during the effective time of the first flexible algorithm based on the status of each link of the tidal network during the effective time period of the first flexible algorithm. The first network topology corresponds to the network topology represented by the dotted line in FIG12 . The second network topology for use during the effective time of the second flexible algorithm can be generated based on the status of each link of the tidal network during the effective time period of the second flexible algorithm. The second network topology corresponds to the network topology represented by the solid line in FIG12 .

[0122] 5. Calculate routing information. During or before the effective time of the first flexible algorithm, in the first network topology corresponding to the first flexible algorithm, perform routing calculation based on the routing constraints of the first flexible algorithm to obtain first routing information. During or before the effective time of the second flexible algorithm, in the second network topology corresponding to the second flexible algorithm, perform routing calculation based on the routing constraints of the second flexible algorithm to obtain second routing information. Optionally, if notification information regarding link changes in the first network topology is received outside the effective time period of the first flexible algorithm, the notification information is stored until the first flexible algorithm is about to take effect, for example, 5 minutes before the effective time of the first flexible algorithm. The network topology is determined and routing calculation is performed based on the latest notification information regarding link changes. This can reduce unnecessary routing calculations and updates to forwarding entries.

[0123] 6. Select SID encapsulation and forwarding. Taking the first message as an example, the head node device of the Tide Network that receives the first message encapsulates the SID or IP prefix corresponding to different flexible algorithms in the first message according to the arrival time of the first message to obtain the second message. For example, the SID of algo:128 encapsulated in the first message arriving between (t0-t1) is 10065, and the SID of algo:129 encapsulated in the first message arriving between (t1-t2) is 20065. Furthermore, the intermediate node device that transmits the second message can look up the corresponding forwarding table entry according to the SID in the second message and forward it.

[0124] Referring to Figure 13, taking a satellite network and a flexible algorithm as an example, while the satellite network's network topology does not exhibit significant periodic changes, it is predictable. Therefore, in the predictable link change scenario described in step 1, Notifying Link Changes, any network device in the satellite network can announce future state changes of directly connected links to other devices in the satellite network. Alternatively, management can distribute future state changes of the network topology to each network device in the satellite network. For example, the predicted future state change for link 1 is to open at time t0 and close at time t1.

[0125] For 2 shown in Figure 13, in the definition of flexible algorithms, two flexible algorithms, a first flexible algorithm and a second flexible algorithm, can be defined on any network device in the satellite network. The effective time period of the first flexible algorithm corresponds to the current time period (t2-t3), and the effective time period of the second flexible algorithm corresponds to the next time period (t3-t4). t2, t3, and t4 can be flexibly set according to the actual changes in the time-varying network, wherein t2 can be the same as t0, and t3 can be the same as t1. This achieves packet loss-free forwarding between different time periods and avoids excessive routing table entries. The time period length is set according to the time-varying network scenario. Optionally, in the scenario shown in Figure 13, the change period T of the effective time of the first flexible algorithm and the second flexible algorithm is the sum of the two time periods. In addition, the implementation methods of 3, 4, 5, and 6 in Figure 13 are consistent with the contents of 3, 4, 5, and 6 in Figure 12, and will not be repeated here.

[0126] Referring to FIG. 14 , FIG. 14 illustrates another method for defining flexible algorithms in a satellite network scenario, namely, defining multiple non-periodic flexible algorithms and continuously updating them over time. In FIG. 14 , step 2, defining a flexible algorithm, does not define a periodic change in the effective time. Steps 1, 3, 4, 5, and 6 in FIG. 14 are consistent with those in FIG. 13 and are not described here. Steps 5 and 6 in FIG. 14 are not shown. Compared to FIG. 13 , in FIG. 14 , when the expiration time of the first flexible algorithm is reached or is about to be reached, the flexible algorithm for the next time period is redefined based on step 7, defining a flexible algorithm. This means that steps 2-5 need to be re-executed. Optionally, the flexible algorithm defined in step 7 can define a new flexible algorithm ID and a new SID locator or IP prefix, or it can be the same as the flexible algorithm ID and SID locator or IP prefix of the first flexible algorithm after expiration, but the effective time information becomes (t5-t6), and t5 can be the same as t4.

[0127] In summary, this method can obtain predictable network connection status change time information or periodically changing network connection status change time information in advance, and then can construct multiple network topologies that are valid in different time periods by adding valid time information to the routing calculation algorithm, so that when the network connection status changes, the network topology valid at that time can be directly used to calculate the route, thereby achieving flexible network topology switching in a time-varying network. Alternatively, based on the construction of multiple network topologies that are valid in different time periods, multiple routing information of multiple network topologies that are valid in different time periods can be further constructed, so that when the network connection status changes, the routing information valid at that time can be directly used to forward messages, thereby achieving flexible forwarding path switching in a time-varying network.

[0128] The above introduces the method for determining the network topology of the embodiment of the present application. Corresponding to the above method, the embodiment of the present application also provides a device for determining the network topology. Figure 15 is a structural schematic diagram of a device for determining the network topology provided in an embodiment of the present application, and the device is applied to any of the network devices shown in Figure 2 above. Based on the following multiple modules shown in Figure 15, the device for determining the network topology shown in Figure 15 can perform all or part of the operations of the method shown in Figure 3. It should be understood that the device may include more additional modules than the modules shown or omit some of the modules shown therein, and the embodiment of the present application does not limit this. As shown in Figure 15, the device includes:

[0129] The processing module 1501 is configured to perform other operations in addition to the receiving and / or sending related operations performed by the method for determining the network topology shown in FIG3 ;

[0130] The transceiver module 1502 is configured to execute the receiving and / or sending related operations executed by the method for determining the network topology shown in FIG. 3 .

[0131] In a possible implementation, the transceiver module 1502 includes a receiving module and / or a sending module. The receiving module is used to perform reception-related operations, and the sending module is used to perform sending-related operations.

[0132] In one possible implementation, processing module 1501 is configured to determine a first route calculation algorithm based on a first time, the first route calculation algorithm including first validity time information and a first network topology constraint, the first validity time information including the validity time of the first route calculation algorithm, the first validity time information and the first network topology constraint being used to determine a network topology corresponding to the first route calculation algorithm, and the first time being before the validity time of the first route calculation algorithm; and determine a first network topology to be used during the validity time of the first route calculation algorithm based on the first validity time information and the first network topology constraint, wherein the first route calculation algorithm and the first network topology are determined before the validity time of the first route calculation algorithm.

[0133] In a possible implementation, the processing module 1501 is further configured to calculate first routing information of the first network topology based on the first routing calculation algorithm at a second time, where the second time is before the validity period of the first routing calculation algorithm.

[0134] In a possible implementation, the validity period of the first routing calculation algorithm corresponds to the validity period of the first network topology.

[0135] In a possible implementation, the first validity period information further includes a change period of the validity period of the first routing calculation algorithm, and the change period of the validity period of the first routing calculation algorithm corresponds to the change period of the validity period of the first network topology.

[0136] In a possible implementation, the first network topology constraint includes a link color constraint, which is used to constrain the colors of links included in the first network topology. Different colors are used to distinguish different valid times, and the colors of the links included in the first network topology comply with the link color constraint.

[0137] In one possible implementation, processing module 1501 is further configured to determine a second route calculation algorithm based on a third time, where the second route calculation algorithm includes second validity time information and a second network topology constraint, where the second validity time information indicates the validity time of the second route calculation algorithm, where the second validity time information and the second network topology constraint are used to determine a network topology corresponding to the second route calculation algorithm, where the third time is before the validity time of the second route calculation algorithm, where the validity time of the first route calculation algorithm is different from the validity time of the second route calculation algorithm, and where a second network topology is determined to be used during the validity time of the second route calculation algorithm based on the second validity time information and the second network topology constraint, where the second route calculation algorithm and the second network topology are determined before the validity time of the second route calculation algorithm.

[0138] In a possible implementation, the first validity time information further includes a change period of the validity time of the first routing calculation algorithm, and the change period of the validity time of the first routing calculation algorithm is determined based on the first validity time information and the second validity time information.

[0139] In a possible implementation, the first routing calculation algorithm is a flex-algo or a multi-topology algorithm.

[0140] In one possible implementation, the first routing calculation algorithm is flex-algo; the transceiver module 1502 is used to receive an ISIS link state data unit LSP message for announcing the first routing calculation algorithm, the first routing calculation algorithm is carried in the FAD sub-TLV field of the ISIS LSP message, and the first effective time information is carried in the effective time sub-TLV field of the FAD sub-TLV.

[0141] In one possible implementation, the first route calculation algorithm is flex-algo; the transceiver module 1502 is used to receive an OSPF LSA message for announcing the first route calculation algorithm, the first route calculation algorithm is carried in the FAD TLV field of the OSPF LSA message, and the first valid time information is carried in the valid time sub-TLV field of the FAD TLV.

[0142] In one possible implementation, the first routing calculation algorithm is flex-algo; the transceiver module 1502 is used to receive a BGP update message for announcing the first routing calculation algorithm, the first routing calculation algorithm is carried in the FAD TLV field of the BGP update message, and the first valid time information is carried in the valid time sub-TLV field of the FAD TLV.

[0143] In one possible implementation, the first routing calculation algorithm is a multi-topology algorithm; the transceiver module 1502 is configured to receive an ISIS LSP message for announcing the first routing calculation algorithm, the first routing calculation algorithm being carried in a time-varying MT information sub-TLV field of the ISIS LSP message, and the first effective time information being carried in an effective time sub-TLV field of the time-varying MT information sub-TLV.

[0144] In one possible implementation, the first routing calculation algorithm is a multi-topology algorithm; the transceiver module 1502 is used to receive an Open Shortest Path First (OSPF) link state advertisement (LSA) message used to announce the first routing calculation algorithm, the first routing calculation algorithm is carried in the time-varying MT information TLV field of the OSPF LSA message, and the first effective time information is carried in the effective time sub-TLV field of the time-varying MT information TLV.

[0145] In one possible implementation, the first routing calculation algorithm is a multi-topology algorithm; the transceiver module 1502 is used to receive a BGP update message for announcing the first routing calculation algorithm, the first routing calculation algorithm is carried in the time-varying MT information TLV field of the BGP update message, and the first effective time information is carried in the effective time sub-TLV field of the time-varying MT information TLV.

[0146] It should be understood that the device provided in FIG15 is only used as an example to illustrate the division of the above-mentioned functional modules when implementing its functions. In actual applications, the above-mentioned functions can be distributed to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the device and method embodiments provided in the above embodiments belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here. The beneficial effects of the device provided in FIG15 can be referred to the beneficial effects of the method shown in FIG3 and will not be repeated here.

[0147] Referring to Figure 16 , Figure 16 shows a schematic diagram of the structure of a network device 2000 provided in an exemplary embodiment of the present application. The network device 2000 shown in Figure 16 is used to perform the operations involved in the method for determining the network topology shown in Figure 3 . The network device 2000 is, for example, a switch, a router, etc., and can be implemented using a general bus architecture.

[0148] As shown in FIG. 16 , the network device 2000 includes at least one processor 2001 , a memory 2003 , and at least one communication interface 2004 .

[0149] The processor 2001 is, for example, a general-purpose central processing unit (CPU), a digital signal processor (DSP), a network processor (NP), a graphics processing unit (GPU), a neural-network processing unit (NPU), a data processing unit (DPU), a microprocessor, or one or more integrated circuits for implementing the solution of the present application. For example, the processor 2001 includes an application-specific integrated circuit (ASIC), a programmable logic device (PLD) or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The PLD is, for example, a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof. It can implement or execute the various logic blocks, modules, and circuits described in conjunction with the disclosure of the embodiments of the present invention. The processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like.

[0150] Optionally, network device 2000 also includes a bus. The bus is used to transmit information between the various components of network device 2000. The bus may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, for example. Buses can be classified as address buses, data buses, control buses, etc. For ease of illustration, FIG16 shows only one line, but this does not mean that there is only one bus or only one type of bus.

[0151] The memory 2003 is, for example, a read-only memory (ROM) or other type of static storage device that can store static information and instructions, or a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 2003 is, for example, independent and connected to the processor 2001 via a bus. The memory 2003 can also be integrated with the processor 2001.

[0152] The communication interface 2004 uses any transceiver-like device for communicating with other devices or communication networks. The communication network can be Ethernet, a radio access network (RAN), or a wireless local area network (WLAN). The communication interface 2004 can include a wired communication interface or a wireless communication interface. Specifically, the communication interface 2004 can be an Ethernet interface, a Fast Ethernet (FE) interface, a Gigabit Ethernet (GE) interface, an Asynchronous Transfer Mode (ATM) interface, a wireless local area network (WLAN) interface, a cellular network communication interface, or a combination thereof. The Ethernet interface can be an optical interface, an electrical interface, or a combination thereof. In the embodiment of the present application, the communication interface 2004 can be used for the network device 2000 to communicate with other devices.

[0153] In a specific implementation, as an embodiment, the processor 2001 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG16 . Each of these processors may be a single-core CPU processor or a multi-core CPU processor. The processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0154] In a specific implementation, as an embodiment, the network device 2000 may include multiple processors, such as the processor 2001 and the processor 2005 shown in Figure 16. Each of these processors may be a single-core CPU or a multi-core CPU. The processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (such as computer program instructions).

[0155] In a specific implementation, as an embodiment, the network device 2000 may further include an output device and an input device. The output device communicates with the processor 2001 and can display information in a variety of ways. For example, the output device can be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector. The input device communicates with the processor 2001 and can receive user input in a variety of ways. For example, the input device can be a mouse, a keyboard, a touch screen device, or a sensor device.

[0156] In some embodiments, the memory 2003 is used to store program code 2010 for executing the solution of the present application, and the processor 2001 can execute the program code 2010 stored in the memory 2003. That is, the network device 2000 can implement the method for determining the network topology provided in the method embodiment through the processor 2001 and the program code 2010 in the memory 2003. The program code 2010 may include one or more software modules. Optionally, the processor 2001 itself may also store program code or instructions for executing the solution of the present application.

[0157] In a specific embodiment, the network device 2000 of the embodiment of the present application may correspond to any network device in the above-mentioned method embodiments, and the processor 2001 in the network device 2000 reads the instructions in the memory 2003, so that the network device 2000 shown in Figure 16 can execute all or part of the operations performed by the method shown in Figure 3.

[0158] Specifically, the processor 2001 is used to determine a first routing calculation algorithm based on a first time, the first routing calculation algorithm includes first effective time information and a first network topology constraint, the first effective time information includes the effective time of the first routing calculation algorithm, the first effective time information and the first network topology constraint are used to determine the network topology corresponding to the first routing calculation algorithm, and the first time is before the effective time of the first routing calculation algorithm; based on the first effective time information and the first network topology constraint, determine a first network topology used at the effective time of the first routing calculation algorithm, and the first routing calculation algorithm and the first network topology are determined before the effective time of the first routing calculation algorithm.

[0159] For the sake of brevity, other optional implementations will not be described here in detail.

[0160] The network device 2000 may also correspond to the network topology determination apparatus shown in FIG15 , and each functional module in the network topology determination apparatus is implemented using software of the network device 2000. In other words, the functional modules included in the network topology determination apparatus are generated by the processor 2001 of the network device 2000 after reading the program code 2010 stored in the memory 2003.

[0161] Among them, each step of the method for determining the network topology shown in Figure 3 is completed by the hardware integrated logic circuit or software instructions in the processor of the network device 2000. The steps of the method disclosed in conjunction with the embodiments of the present application can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware. To avoid repetition, it will not be described in detail here.

[0162] Referring to Figure 17 , Figure 17 shows a schematic diagram of the structure of a network device 2100 provided in another exemplary embodiment of the present application. The network device 2100 shown in Figure 17 is used to perform all or part of the operations involved in the method for determining the network topology shown in Figure 3 . The network device 2100 is, for example, a switch, a router, etc., and can be implemented using a general bus architecture.

[0163] As shown in FIG. 17 , the network device 2100 includes a main control board 2110 and an interface board 2130 .

[0164] The main control board (MCB), also known as the main processing unit (MPU) or route processor card, is used to control and manage various components in network device 2100, including routing calculations, device management, device maintenance, and protocol processing. MCB 2110 includes a central processing unit (CPU) 2111 and memory 2112.

[0165] Interface board 2130 is also known as a line processing unit (LPU), line card, or service board. It provides various service interfaces and implements data packet forwarding. Service interfaces include, but are not limited to, Ethernet interfaces and POS (Packet over SONET / SDH) interfaces. Ethernet interfaces, for example, are Flexible Ethernet Clients (FlexE Clients) interfaces. Interface board 2130 includes a central processing unit (CPU) 2131, a network processor (NPU) 2132, a forwarding table memory 2134, and a physical interface card (PIC) 2133.

[0166] The central processing unit 2131 on the interface board 2130 is used to control and manage the interface board 2130 and communicate with the central processing unit 2111 on the main control board 2110 .

[0167] The network processor 2132 is used to implement message forwarding processing. The network processor 2132 can be in the form of a forwarding chip. The forwarding chip can be a network processor (NP). In some embodiments, the forwarding chip can be implemented using an application-specific integrated circuit (ASIC) or a field programmable gate array (FPGA). Specifically, the network processor 2132 is used to forward received messages based on the forwarding table stored in the forwarding entry memory 2134. If the destination address of the message is the address of the network device 2100, the message is sent to the CPU (such as the central processing unit 2131) for processing. If the destination address of the message is not the address of the network device 2100, the next hop and outgoing interface corresponding to the destination address are searched in the forwarding table based on the destination address, and the message is forwarded to the outgoing interface corresponding to the destination address. Processing of uplink messages can include processing the message inbound interface and forwarding table lookup; processing of downlink messages can include forwarding table lookup, etc. In some embodiments, the central processing unit can also perform the functions of the forwarding chip, such as implementing software forwarding based on a general-purpose CPU, thereby eliminating the need for a forwarding chip in the interface board.

[0168] Physical interface card 2133 implements physical layer interconnection. Raw traffic enters interface board 2130 through this card, and processed packets are sent out from this physical interface card 2133. Physical interface card 2133, also known as a daughter card, can be installed on interface board 2130. It converts optical and electrical signals into packets, performs a validity check on these packets, and then forwards them to network processor 2132 for processing. In some embodiments, central processing unit 2131 can also perform the functions of network processor 2132, such as implementing software forwarding based on a general-purpose CPU, thus eliminating the need for network processor 2132 in physical interface card 2133.

[0169] Optionally, the network device 2100 includes multiple interface boards. For example, the network device 2100 further includes an interface board 2140. The interface board 2140 includes a central processing unit 2141, a network processor 2142, a forwarding table entry memory 2144, and a physical interface card 2143. The functions and implementation of each component in the interface board 2140 are the same as or similar to those of the interface board 2130 and are not described in detail here.

[0170] Optionally, network device 2100 further includes a switching fabric board 2120. Switching fabric board 2120 may also be referred to as a switch fabric unit (SFU). If network device 2100 includes multiple interface boards, switching fabric board 2120 is used to exchange data between the interface boards. For example, interface board 2130 and interface board 2140 can communicate via switching fabric board 2120.

[0171] The main control board 2110 is coupled to the interface board. For example, the main control board 2110, the interface board 2130, the interface board 2140, and the switching network board 2120 are connected to the system backplane via a system bus to achieve intercommunication. In one possible implementation, an inter-process communication (IPC) channel is established between the main control board 2110 and the interface boards 2130 and 2140, and communication is performed between the main control board 2110 and the interface boards 2130 and 2140 via the IPC channel.

[0172] Logically, network device 2100 includes a control plane and a forwarding plane. The control plane includes a main control board 2110 and a central processing unit (CPU) 2111. The forwarding plane includes various components that perform forwarding, such as a forwarding table entry memory 2134, physical interface cards 2133, and a network processor 2132. The control plane performs routing functions, generates forwarding tables, processes signaling and protocol messages, and configures and maintains the network device's status. The control plane sends the generated forwarding tables to the forwarding plane. On the forwarding plane, the network processor 2132 forwards messages received by the physical interface card 2133 based on the forwarding tables sent by the control plane. The forwarding tables sent by the control plane can be stored in the forwarding table entry memory 2134. In some embodiments, the control plane and forwarding plane can be completely separate and not located on the same network device.

[0173] It's worth noting that there may be one or more main control boards (SPUs), which can include both active and standby SPUs. There may also be one or more interface boards. The higher the network device's data processing capabilities, the more interface boards it provides. Interface boards can also have one or more physical interface cards. There may be no SPUs, one or more SPUs, and multiple SPUs can provide load balancing and redundancy. In a centralized forwarding architecture, network devices may not require SPUs; the interface boards handle service data processing for the entire system. In a distributed forwarding architecture, network devices may have at least one SPU, which enables data exchange between multiple interface boards, providing high-capacity data exchange and processing capabilities. Therefore, network devices with distributed architectures have greater data access and processing capabilities than those with centralized architectures. Alternatively, a network device can consist of a single card, without a switching fabric board (SFB), integrating the functions of the interface board and the main control board. In this case, the central processing unit (CPU) on the interface board and the CPU on the main control board can be combined into a single CPU on this card, performing the combined functions of the two. This type of network device has lower data exchange and processing capabilities (for example, low-end network devices such as switches or routers). The specific architecture used depends on the specific network deployment scenario and is not specified here.

[0174] In a specific embodiment, the network device 2100 corresponds to the apparatus for determining the network topology shown in FIG15 . In some embodiments, the processing module 1501 in the apparatus for determining the network topology shown in FIG15 corresponds to the central processing unit 2111 or the network processor 2132 in the network device 2100 , and the transceiver module 1502 corresponds to the physical interface card 2133 in the network device 2100 .

[0175] It should be understood that the processor described above may be a CPU, or other general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. It is worth noting that the processor may be a processor that supports the Advanced Reduced Instruction Set Machine (ARM) architecture.

[0176] Furthermore, in an optional embodiment, the memory may include a read-only memory and a random access memory, and provide instructions and data to the processor. The memory may also include a non-volatile random access memory. For example, the memory may also store device type information.

[0177] The memory may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM), which is used as an external cache memory. By way of example and not limitation, many forms of RAM are available. For example, static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronized dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0178] An embodiment of the present application further provides a computer-readable storage medium, in which at least one instruction is stored. The instruction is loaded and executed by a processor to enable a computer to implement any of the above methods for determining a network topology.

[0179] The embodiments of the present application further provide a computer program (product), which, when executed by a computer, can enable a processor or computer to execute the corresponding steps and / or processes in the above method embodiments.

[0180] An embodiment of the present application also provides a chip, including a processor, for calling and executing instructions stored in a memory, so that a communication device equipped with the chip executes any of the above methods for determining a network topology.

[0181] An embodiment of the present application also provides another chip, including: an input interface, an output interface, a processor and a memory, wherein the input interface, the output interface, the processor and the memory are connected through an internal connection path, and the processor is used to execute the code in the memory. When the code is executed, the processor is used to execute any of the above network topology determination methods.

[0182] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions according to the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state drive).

[0183] Those skilled in the art will appreciate that the various method steps and modules described in conjunction with the embodiments disclosed herein can be implemented in software, hardware, firmware, or any combination thereof. In order to clearly illustrate the interchangeability of hardware and software, the steps and components of each embodiment have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may 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 this application.

[0184] Those skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or may be accomplished by a program to instruct the relevant hardware, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0185] When software is used for implementation, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer program instructions. As an example, the method of the embodiment of the present application can be described in the context of a machine executable instruction, and the machine executable instruction is such as included in the program module executed in the device on the real or virtual processor of the target. Generally speaking, a program module includes a routine, a program, a library, an object, a class, a component, a data structure, etc., which performs a specific task or realizes a specific abstract data structure. In various embodiments, the function of the program module can be merged or split between the described program modules. The machine executable instruction for the program module can be executed in a local or distributed device. In a distributed device, the program module can be located in both a local and a remote storage medium.

[0186] The computer program code for realizing the method for the embodiment of the application can be written in one or more programming languages.These computer program codes can be provided to the processor of general-purpose computer, special-purpose computer or other programmable data processing device, so that program code, when being executed by computer or other programmable data processing device, causes the function / operation specified in flow chart and / or block diagram to be implemented.Program code can be executed completely on computer, partly on computer, as independent software package, partly on computer and partly on remote computer or completely on remote computer or server.

[0187] In the context of the embodiments of the present application, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, and the like.

[0188] Examples of signals may include electrical, optical, radio, acoustic or other forms of propagated signals, such as carrier waves, infrared signals, etc.

[0189] A machine-readable medium may be any tangible medium that contains or stores a program for or in connection with an instruction execution system, apparatus, or device. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More detailed examples of machine-readable storage media include an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0190] Those skilled in the art will clearly understand that, for the sake of convenience and brevity of description, the specific working processes of the above-described systems, devices, and modules can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0191] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the modules is merely a logical function division. In actual implementation, there may be other division methods, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules, or can be electrical, mechanical or other forms of connection.

[0192] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0193] In addition, the functional modules in the various embodiments of the present application may be integrated into a processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The above-mentioned integrated modules may be implemented in the form of hardware or software functional modules.

[0194] If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0195] In this application, the terms "first", "second", etc. are used to distinguish between identical or similar items having substantially the same effects and functions. It should be understood that there is no logical or temporal dependency between "first", "second", and "nth", nor is there a limit on quantity and execution order. It should also be understood that although the following description uses the terms first, second, etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of various examples, the first effective time information can be referred to as the second effective time information, and similarly, the second effective time information can be referred to as the first effective time information. Both the first effective time information and the second effective time information can be effective time information, and in some cases, can be separate and different effective time information.

[0196] It should also be understood that in the various embodiments of the present application, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0197] In this application, the term "at least one" means one or more, and the term "plurality" means two or more. For example, "plurality of second messages" means two or more second messages. The terms "system" and "network" are often used interchangeably herein.

[0198] It should be understood that the terminology used in the description of the various examples herein is for the purpose of describing particular examples only and is not intended to be limiting. As used in the description of the various examples and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0199] It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the listed items. The term "and / or" describes an association between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this application generally indicates that the associated objects are in an "or" relationship.

[0200] It will also be understood that the term “comprise” (also known as “includes,” “including,” “comprises,” and / or “comprising”) when used in this specification specifies the presence of stated features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0201] It should also be understood that the terms “if” and “if” may be interpreted to mean “when” or “upon” or “in response to determining” or “in response to detecting.” Similarly, the phrases “if it is determined that ” or “if [stated condition or event] is detected” may be interpreted to mean “upon determining ” or “in response to determining ” or “upon detecting [stated condition or event]” or “in response to detecting [stated condition or event],” depending on the context.

[0202] It should be understood that determining B based on A does not mean determining B based solely on A. B can also be determined based on A and / or other information.

[0203] It should also be understood that references throughout this specification to "one embodiment," "an embodiment," or "one possible implementation" mean that specific features, structures, or characteristics associated with that embodiment or implementation are included in at least one embodiment of the present application. Therefore, the appearance of "in one embodiment," "in an embodiment," or "one possible implementation" throughout this specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0204] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for determining a network topology, characterized in that: The method comprises: Determine a first route calculation algorithm according to a first time, the first route calculation algorithm includes first effective time information and a first network topology constraint, the first effective time information includes the effective time of the first route calculation algorithm, the first effective time information and the first network topology constraint are used to determine the network topology corresponding to the first route calculation algorithm, and the first time is before the effective time of the first route calculation algorithm; A first network topology used during the validity period of the first route calculation algorithm is determined based on the first validity period information and the first network topology constraint, wherein the first route calculation algorithm and the first network topology are determined before the validity period of the first route calculation algorithm.

2. The method according to claim 1, characterized in that After determining the first network topology used during the effective time of the first routing calculation algorithm based on the first effective time information and the first network topology constraint, the method further includes: At a second time, first routing information of the first network topology is calculated based on the first routing calculation algorithm, and the second time is before the effective time of the first routing calculation algorithm.

3. The method according to claim 1 or 2, characterized in that: The validity period of the first routing calculation algorithm corresponds to the validity period of the first network topology.

4. The method according to any one of claims 1 to 3, characterized in that: The first effective time information further includes a change period of the effective time of the first routing calculation algorithm, and the change period of the effective time of the first routing calculation algorithm corresponds to the change period of the effective time of the first network topology.

5. The method according to any one of claims 1 to 4, characterized in that: The first network topology constraint includes a link color constraint, and the link color constraint is used to constrain the colors of the links included in the first network topology. Different colors are used to distinguish different valid times. The colors of the links included in the first network topology comply with the link color constraint.

6. The method according to claim 1 or 2, characterized in that: The method further comprises: Determine a second route calculation algorithm according to a third time, the second route calculation algorithm includes second effective time information and a second network topology constraint, the second effective time information indicates the effective time of the second route calculation algorithm, the second effective time information and the second network topology constraint are used to determine the network topology corresponding to the second route calculation algorithm, the third time is before the effective time of the second route calculation algorithm, and the effective time of the first route calculation algorithm is different from the effective time of the second route calculation algorithm; A second network topology used at the effective time of the second route calculation algorithm is determined based on the second effective time information and the second network topology constraint, the second route calculation algorithm and the second network topology being determined before the effective time of the second route calculation algorithm.

7. The method according to claim 6, characterized in that The first effective time information further includes a change period of the effective time of the first routing calculation algorithm, and the change period of the effective time of the first routing calculation algorithm is determined based on the first effective time information and the second effective time information.

8. The method according to any one of claims 1 to 7, characterized in that: The first routing calculation algorithm is a flexible algorithm flex-algo or a multi-topology algorithm.

9. The method according to any one of claims 1 to 8, characterized in that: The first routing calculation algorithm is a flexible algorithm flex-algo; Before determining the first route calculation algorithm according to the first time, the method further includes: Receive an Intermediate System to Intermediate System Protocol ISIS Link State Data Unit LSP message for announcing the first routing calculation algorithm, The first route calculation algorithm is carried in the flexible algorithm definition FAD subtype, length, value sub-TLV field of the ISIS LSP message, and the first effective time information is carried in the effective time sub-TLV field of the FAD sub-TLV.

10. The method according to any one of claims 1 to 8, characterized in that: The first route calculation algorithm is a flexible algorithm flex-algo; before determining the first route calculation algorithm according to the first time, the method further includes: An Open Shortest Route First (OSPF) link state advertisement (LSA) message is received for announcing the first route calculation algorithm. The first route calculation algorithm is carried in the flexible algorithm definition type, length, and value FAD TLV field of the OSPF LSA message. The first valid time information is carried in the valid time sub-TLV field of the FAD TLV.

11. The method according to any one of claims 1 to 8, characterized in that: The first routing calculation algorithm is a flexible algorithm flex-algo; Before determining the first route calculation algorithm according to the first time, the method further includes: A Border Gateway Protocol (BGP) update message is received for announcing the first routing calculation algorithm, wherein the first routing calculation algorithm is carried in the flexible algorithm definition type, length, and value FAD TLV field of the BGP update message, and the first valid time information is carried in the valid time sub-TLV field of the FAD TLV.

12. The method according to any one of claims 1 to 8, characterized in that: The first routing calculation algorithm is a multi-topology algorithm; before determining the first routing calculation algorithm according to the first time, the method further includes: An Intermediate System to Intermediate System Protocol ISIS Link State Data Unit LSP message is received for announcing the first routing calculation algorithm, wherein the first routing calculation algorithm is carried in the time-varying multi-topology MT information subtype, length, and value sub-TLV fields of the ISIS LSP message, and the first valid time information is carried in the valid time sub-TLV field of the time-varying MT information sub-TLV.

13. The method according to any one of claims 1 to 8, characterized in that: The first routing calculation algorithm is a multi-topology algorithm; before determining the first routing calculation algorithm according to the first time, the method further includes: An Open Shortest Route First protocol OSPF link state advertisement LSA message is received for announcing the first routing calculation algorithm, wherein the first routing calculation algorithm is carried in the time-varying multi-topology MT information type, length, and value TLV fields of the OSPF LSA message, and the first valid time information is carried in the valid time sub-TLV field of the time-varying MT information TLV.

14. The method according to any one of claims 1 to 8, characterized in that: The first routing calculation algorithm is a multi-topology algorithm; before determining the first routing calculation algorithm according to the first time, the method further includes: A Border Gateway Protocol (BGP) update message for announcing the first routing calculation algorithm is received, wherein the first routing calculation algorithm is carried in the time-varying multi-topology MT information type, length, and value TLV fields of the BGP update message, and the first valid time information is carried in the valid time sub-TLV field of the time-varying MT information TLV.

15. A device for determining a network topology, characterized in that: The device comprises: A processing module, used to perform other operations other than the operations related to receiving and / or sending in the method for determining the network topology according to any one of claims 1 to 14; A transceiver module, used to perform reception and / or transmission related operations in the method for determining the network topology according to any one of claims 1 to 14.

16. A network device, characterized in that: The network device includes: a processor, the processor is coupled to a memory, the memory stores at least one program instruction or code, and the at least one program instruction or code is loaded and executed by the processor so that the network device implements the method for determining the network topology described in any one of claims 1-14.

17. A computer-readable storage medium, characterized in that: The computer storage medium stores at least one instruction, and the at least one instruction is loaded and executed by the processor so that the computer implements the method for determining the network topology as described in any one of claims 1-14.

18. A computer program product, characterized in that The computer program product comprises: a computer program code, wherein the computer program code is loaded and executed by a computer so as to enable the computer to implement the method for determining the network topology according to any one of claims 1 to 14.

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