A multi-link switchover control method and device

Abstract

The application discloses a kind of multi-link switching control method and device.The method is applied to multi-link switching control device, the device includes: at least two wide area network side three layers of network port, at least two local area network side two layers of network port, three layer interface, two layer interface, main control circuit board and shell, the method includes: by the main control circuit board obtains external switching instruction;If the external switching instruction indicates that switching of the satellite communication link is carried out in the data link layer, then by the main control circuit board, two layer target link switching operation is executed in the data link layer;If the external switching instruction indicates that switching of the satellite communication link is carried out in the network layer, then by the main control circuit board, three layer target link switching operation is executed in the network layer.Avoid the service interruption when satellite communication link switching is carried out in data link layer, so that terminal equipment identification can be actively updated IP address.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and in particular to a multi-link switching control method and apparatus. Background Technology

[0002] In mobile satellite communications or mission-critical high-reliability scenarios, dual-satellite modem hot backup is a common redundancy deployment method. Satellite modems typically provide both Layer 2 (data link layer) and Layer 3 (network layer) network interfaces to meet the access requirements of different terminals and services.

[0003] When switching satellite communication links involving different satellite modems, existing technologies typically achieve Layer 2 switching by directly shutting down the old network port (Down) and enabling the new network port (Up). However, after the network port is powered back on, rate auto-negotiation and link training are required, a process that usually takes 1-3 seconds, causing service interruption. Existing technologies use Layer 3 bridging switching for Layer 3 satellite communication link switching. After switching to the new satellite communication link, the terminal device is completely unaware of the change in the satellite communication link, and the terminal does not proactively initiate an IP address update. Summary of the Invention

[0004] This invention provides a multi-link switching control method and apparatus to solve the problems of service interruption during satellite communication link switching at the data link layer and the inability of terminals to proactively update their Internet Protocol (IP) addresses in real time at the network layer.

[0005] According to one aspect of the present invention, a multi-link switching control method is provided, applied to a multi-link switching control device. The multi-link switching control device includes: at least two WAN-side Layer 3 ports, at least two LAN-side Layer 2 ports, a Layer 3 interface, a Layer 2 interface, a main control circuit board, and a housing. The main control circuit board includes a central processing unit (CPU) and an Ethernet switching chip. The Ethernet switching chip includes registers. The Layer 3 interface and the Layer 2 interface are used to connect to external terminal devices of the multi-link switching control device. The method includes: The main control circuit board obtains external switching instructions, which include instructions in the data link layer or the network layer to switch satellite communication links of different satellite modems. The satellite communication links include the communication links between the terminal device, the satellite modem, and the satellites corresponding to the satellite modem. If the external switching command instructs the switching of the satellite communication link in the data link layer, then the main control circuit board performs a Layer 2 target link switching operation in the data link layer. If the external switching command instructs the switching of the satellite communication link in the network layer, then the three-layer target link switching operation is performed in the network layer through the main control circuit board; The Layer 2 target link switching operation includes, in the data link layer, configuring the local area network side Layer 2 port to switch the satellite communication link from the original Layer 2 link to the Layer 2 target link without closing the local area network side Layer 2 port; The three-layer target link switching operation includes, in the network layer, configuring the WAN-side three-layer network port and the three-layer interface, and based on a set time range, switching the satellite communication link from the original three-layer link to the three-layer target link.

[0006] According to another aspect of the present invention, a multi-link switching control device is provided, comprising: The device includes at least two WAN-side Layer 3 ports, at least two LAN-side Layer 2 ports, a Layer 3 interface, a Layer 2 interface, a main control circuit board, and a housing. The main control circuit board includes a central processing unit and an Ethernet switching chip. The Ethernet switching chip includes registers. The Layer 3 interface and the Layer 2 interface are used to connect to external terminal devices of the multi-link switching control device. The main control circuit board is connected to the WAN-side Layer 3 network port, the LAN-side Layer 2 network port, the Layer 3 interface, and the Layer 2 interface, and is used to obtain external switching instructions. If the external switching instruction indicates that the satellite communication link should be switched in the data link layer, then a Layer 2 target link switching operation is performed in the data link layer; if the external switching instruction indicates that the satellite communication link should be switched in the network layer, then a Layer 3 target link switching operation is performed in the network layer. The Layer 2 target link switching operation includes, in the data link layer, configuring the local area network side Layer 2 port to switch the satellite communication link from the original Layer 2 link to the Layer 2 target link without closing the local area network side Layer 2 port; The three-layer target link switching operation includes, in the network layer, configuring the WAN-side three-layer network port and the three-layer interface, and based on a set time range, switching the satellite communication link from the original three-layer link to the three-layer target link.

[0007] The technical solution of this invention involves obtaining an external switching instruction via the main control circuit board. This external switching instruction includes instructions to switch satellite communication links between different satellite modems in the data link layer or the network layer. The satellite communication link includes the communication link between the terminal device, the satellite modem, and the satellite corresponding to the satellite modem. If the external switching instruction indicates switching of the satellite communication link in the data link layer, then the main control circuit board performs a Layer 2 target link switching operation in the data link layer. If the external switching instruction indicates switching in the network layer... The switching of the satellite communication link is performed through the main control circuit board at the network layer, executing a Layer 3 target link switching operation. Specifically, the Layer 2 target link switching operation includes, at the data link layer, configuring the LAN-side Layer 2 port to switch the satellite communication link from the original Layer 2 link to the target Layer 2 link without closing the LAN-side Layer 2 port. The Layer 3 target link switching operation includes, at the network layer, configuring the WAN-side Layer 3 port and the Layer 3 interface to switch the satellite communication link from the original Layer 3 link to the target Layer 3 link based on a set time range. This embodiment of the invention ensures that the LAN-side Layer 2 port remains open during the Layer 2 target link switching operation, avoiding service interruption during satellite communication link switching at the data link layer. By setting a time range for the Layer 3 target link switching operation, it ensures that the terminal device recognizes the disconnected state of the original Layer 3 link and triggers a reconnection mechanism to actively update the IP address. It also ensures that the reconnection time of the Layer 3 target link does not exceed the set time range, reducing network interruption time.

[0008] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a flowchart of a multi-link switching control method provided in Embodiment 1 of the present invention; Figure 2 This is a flowchart of a multi-link switching control method provided in Embodiment 2 of the present invention; Figure 3This is a flowchart of a multi-link switching control method in the data link layer provided by an embodiment of the present invention; Figure 4 This is a flowchart of a multi-link switching control method provided in Embodiment 3 of the present invention; Figure 5 This is a flowchart of a multi-link switching control method in the network layer provided by an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a multi-link switching control device provided in Embodiment 4 of the present invention; Figure 7 This is a schematic diagram illustrating an application scenario of a multi-link switching control device provided in an embodiment of the present invention. Detailed Implementation

[0011] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0012] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0013] Example 1 Figure 1 This is a flowchart of a multi-link switching control method provided in Embodiment 1 of the present invention. This embodiment is applicable to situations where a multi-link switching control device performs satellite modem switching. The method can be executed by a multi-link switching control device, which can be implemented in hardware and / or software and can be configured in an electronic device. For example, the electronic device can be a drone, a vehicle-mounted terminal, or a shelter. Figure 1As shown, an application is made to a multi-link switching control device. The multi-link switching control device includes: at least two WAN-side Layer 3 ports, at least two LAN-side Layer 2 ports, a Layer 3 interface, a Layer 2 interface, a main control circuit board, and a housing. The main control circuit board includes a central processing unit (CPU) and an Ethernet switching chip. The Ethernet switching chip includes registers. The Layer 3 interface and the Layer 2 interface are used to connect external terminal devices to the multi-link switching control device. The method includes: S110. Obtain an external switching instruction through the main control circuit board. The external switching instruction includes an instruction to switch the satellite communication links of different satellite modems in the data link layer or the network layer. The satellite communication link includes the communication link between the terminal device, the satellite modem, and the satellite corresponding to the satellite modem.

[0014] In this embodiment, the main control circuit board can be the main control circuit board used to perform satellite modem switching in a multi-link switching control device. The main control circuit board can house a Central Processing Unit (CPU) and an Ethernet switching chip. The Ethernet switching chip includes registers. These registers can be used to store the status of each pin of the Ethernet switching chip and the status of each network interface connected to the local area network (LAN) and wide area network (WAN). The external switching command can be an instruction received by the CPU in the main control circuit board through an interface. The external switching command can be in the form of a General-Purpose Input / Output (GPIO) level signal or a network control message. The external switching command can instruct the primary / backup switching of the satellite modem at the data link layer or network layer. The satellite communication link can be a communication link including a satellite modem. The satellite communication link can include a communication link between the terminal device and the satellite modem, or a communication link between the satellite modem and the satellite corresponding to the satellite modem. The external switching command instructs the switching of the satellite modem, which can manifest as a switching of satellite communication links including different satellite modems. The Layer 2 interface can be a network interface in the data link layer used to establish a connection with the terminal device. The Layer 3 interface can be a network interface in the network layer used to establish a connection with the terminal device. The Layer 2 and Layer 3 interfaces can establish connections with terminal devices via either wired or wireless connections, and this invention does not impose any restrictions on this.

[0015] Specifically, the CPU on the main control circuit board receives external switching commands through an interface, parses the external switching commands, and determines whether the satellite communication link switching is performed at the data link layer or the network layer.

[0016] Optionally, the external switching instruction includes a network mode identifier and a target link identifier, wherein the network mode identifier includes an identifier indicating the data link layer or the network layer, and the target link identifier indicates a satellite communication link including a target satellite modem.

[0017] In this embodiment, the network mode identifier can be a data link layer identifier or a network layer identifier. The target link identifier can be an identifier indicating the satellite communication link where the satellite modem to be switched resides. The target satellite modem can be the satellite modem to be switched.

[0018] Specifically, the satellite communication link switching can be determined at the data link layer or the network layer based on the network mode identifier, and the satellite communication link including the target satellite modem can be determined based on the target link identifier.

[0019] S120. If the external switching command instructs the switching of the satellite communication link in the data link layer, then the main control circuit board performs a Layer 2 target link switching operation in the data link layer and ends the execution.

[0020] The Layer 2 target link switching operation includes, in the data link layer, configuring the local area network (LAN) side Layer 2 port to switch the satellite communication link from the original Layer 2 link to the target Layer 2 link without closing the LAN side Layer 2 port.

[0021] In this embodiment, the Layer 2 target link switching operation can be performed at the data link layer to switch the satellite communication link. The LAN-side Layer 2 port can be an Ethernet interface provided by the multi-link switching control device for connecting to a satellite modem on the LAN side. The LAN-side Layer 2 port operates at the data link layer. The number of LAN-side Layer 2 ports can be at least two. Each LAN-side Layer 2 port establishes a connection with one satellite modem. The connection between the LAN-side Layer 2 port and the satellite modem can be wired or wireless; this invention does not impose any limitations. The original Layer 2 link can include the satellite communication link before the switch. The original Layer 2 link can include the satellite modem to be switched. The target Layer 2 link is the satellite communication link to be switched. The target Layer 2 link can include the satellite modem to be switched. The satellite modems in the original Layer 2 link and the target Layer 2 link are not distinguished as primary or backup; a switch can be made from an original Layer 2 link including the primary satellite modem to a target Layer 2 link including the backup satellite modem, or vice versa.

[0022] Specifically, if the external switching command instructs that the satellite communication link be switched at the data link layer, the CPU in the main control circuit board will configure the status of the local area network side Layer 2 port, and while keeping the local area network side Layer 2 port always open, switch the original Layer 2 link to the Layer 2 target link, and notify the satellite of the terminal device's address, thus completing the execution of the Layer 2 target link switch.

[0023] For example, the switch from the original Layer 2 link to the target Layer 2 link can be completed by setting the status of the Layer 2 port on the LAN side connected to the original Layer 2 link to no longer forward messages, and setting the status of the Layer 2 port on the LAN side connected to the target Layer 2 link to forward messages.

[0024] S130. If the external switching command instructs the switching of the satellite communication link in the network layer, then the three-layer target link switching operation is performed in the network layer through the main control circuit board.

[0025] The three-layer target link switching operation includes, in the network layer, configuring the WAN-side three-layer network port and the three-layer interface, and based on a set time range, switching the satellite communication link from the original three-layer link to the three-layer target link.

[0026] In this embodiment, the Layer 3 target link switching operation can be a satellite communication link switching operation performed at the network layer. The WAN-side Layer 3 port can be an Ethernet interface on the WAN side used to connect to the satellite modem. The WAN-side Layer 3 port can operate at the network layer. The number of WAN-side Layer 3 ports can be at least two. Each WAN-side Layer 3 port can be used to establish a connection with the corresponding satellite modem. The set time range can be the range of time required to establish a connection with the satellite communication link to be switched. The set time range can be determined empirically. The Layer 3 original link can be the satellite communication link in the network layer that needs to be switched. The Layer 3 target link can be the satellite communication link in the network layer that needs to be switched. The satellite modems included in the Layer 3 original link and the Layer 3 target link are not distinguished as primary or backup.

[0027] Specifically, if the external switching command instructs to switch the satellite communication link at the network layer, the CPU on the main control circuit board configures the WAN-side Layer 3 network port, and based on a set time range, disconnects the WAN-side Layer 3 network port connected to the original Layer 3 link and connects the WAN-side Layer 3 network port connected to the target Layer 3 link.

[0028] For example, the set time range specifies the duration of a physical disconnection of the WAN-side Layer 3 network port. If the time is less than the set time range, the terminal device cannot detect the satellite communication link disconnection; if the time is greater than the set time range, the satellite communication link disconnection lasts too long, affecting information forwarding. By switching the satellite communication link within the set time range, the terminal device can detect that the satellite communication link has experienced an explicit physical interruption, forcing the terminal device's local network protocol stack to clear the current IP address lease, and immediately send a message to the satellite modem of the target Layer 3 link through the WAN-side Layer 3 network port. This allows the terminal device to obtain the network IP address in the network layer corresponding to the satellite modem of the target Layer 3 link in a very short time.

[0029] The technical solution of this invention involves obtaining an external switching instruction via the main control circuit board. This external switching instruction includes instructions to switch satellite communication links between different satellite modems in the data link layer or the network layer. The satellite communication link includes the communication link between the terminal device, the satellite modem, and the satellite corresponding to the satellite modem. If the external switching instruction indicates switching of the satellite communication link in the data link layer, then the main control circuit board performs a Layer 2 target link switching operation in the data link layer. If the external switching instruction indicates switching in the network layer... The switching of the satellite communication link is performed through the main control circuit board at the network layer, executing a Layer 3 target link switching operation. Specifically, the Layer 2 target link switching operation includes, at the data link layer, configuring the LAN-side Layer 2 port to switch the satellite communication link from the original Layer 2 link to the target Layer 2 link without closing the LAN-side Layer 2 port. The Layer 3 target link switching operation includes, at the network layer, configuring the WAN-side Layer 3 port and the Layer 3 interface to switch the satellite communication link from the original Layer 3 link to the target Layer 3 link based on a set time range. This embodiment of the invention ensures that the LAN-side Layer 2 port remains open during the Layer 2 target link switching operation, avoiding service interruption during satellite communication link switching at the data link layer. By setting a time range for the Layer 3 target link switching operation, it ensures that the terminal device recognizes the disconnected state of the original Layer 3 link and triggers a reconnection mechanism to actively update the IP address. It also ensures that the reconnection time of the Layer 3 target link does not exceed the set time range, reducing network interruption time.

[0030] Example 2 Figure 2This is a flowchart of a multi-link switching control method provided in Embodiment 2 of the present invention. This embodiment is an optimization based on any of the above embodiments, and mainly includes a detailed description of the process of performing Layer 2 target link switching operations. It should be noted that technical details not described in detail in this embodiment can be found in any of the above embodiments. Figure 2 As shown, the method includes: S210. Obtain an external switching command through the main control circuit board. The external switching command includes an instruction to switch the satellite communication links of different satellite modems in the data link layer or the network layer. The satellite communication link includes the communication link between the terminal device, the satellite modem, and the satellite corresponding to the satellite modem.

[0031] S220. If the external switching instruction indicates that the satellite communication link is switched in the data link layer, then the target local area network side Layer 2 port corresponding to the Layer 2 target link and the original local area network side Layer 2 port corresponding to the original Layer 2 link are determined.

[0032] In this embodiment, the target LAN-side Layer 2 port can be a Layer 2 port in the data link layer used to establish a connection with the target satellite modem. The original LAN-side Layer 2 port can be a Layer 2 port in the data link layer used to establish a connection with the satellite modem that needs to be switched.

[0033] Specifically, the target LAN-side Layer 2 network port that establishes a connection with the target satellite modem is determined based on the target link identifier, such as the external switching instruction, and the original LAN-side Layer 2 network port is determined based on the status of the LAN-side Layer 2 network port.

[0034] S230. Configure the status of the original LAN-side Layer 2 network port and the target LAN-side Layer 2 network port through the Ethernet chip. The status includes indicating that the connection between the terminal device and the satellite modem in the original Layer 2 link is blocked, and the connection between the terminal device and the satellite modem in the target Layer 2 link is enabled.

[0035] In this embodiment, the state can be that the original LAN-side Layer 2 network port and the target LAN-side Layer 2 network port have respectively established connections with the corresponding satellite modem.

[0036] Specifically, the CPU changes the status of the original LAN-side Layer 2 port and the target LAN-side Layer 2 port as indicated by the Ethernet chip, changing the status of the original LAN-side Layer 2 port from being able to forward messages to being stopped from forwarding messages, and changing the status of the target LAN-side Layer 2 port from being stopped from forwarding messages to being able to forward messages.

[0037] S240. Clear the address mapping table in the Ethernet switching chip associated with the original LAN side Layer 2 port and the Layer 2 interface.

[0038] In this embodiment, the address mapping table can be a table used to record the correspondence between the Media Access Control (MAC) address of the terminal device and the Layer 2 network port on the local area network side in the data link layer. When switching satellite communication links, it is necessary to clear the records related to the original Layer 2 link in the address mapping table, and then insert a record of the correspondence between the MAC address of the terminal device and the Layer 2 network port on the target local area network side according to the target Layer 2 link. The address mapping table can be a filtering database (FDB) table, for example.

[0039] Specifically, the CPU sends a command to the Ethernet switching chip to clear the address mapping table, forcibly emptying all address mapping table entries in the Ethernet switching chip associated with the original LAN side Layer 2 network port and Layer 2 interface, avoiding the clearing operation of the entire address mapping table, preventing forwarding interruption in the data link layer, and realizing seamless satellite communication link switching for terminal devices.

[0040] S250. Send Address Resolution Protocol (ARP) information, including the address of the terminal device, to the corresponding satellite modem through the Layer 2 network port on the target local area network side, and then terminate the execution.

[0041] In this embodiment, the Address Resolution Protocol (ARP) information can be information used to notify the target satellite modem terminal device of its address. The address can be the terminal device's MAC address and IP address. The ARP information can be an Address Resolution Protocol (ARP) broadcast packet.

[0042] Specifically, the CPU constructs a gratuitous ARP broadcast packet (i.e., Address Resolution Protocol information) with the source MAC address being the terminal device's MAC address and the source IP address being the terminal device's IP address by listening to or reading the terminal device's MAC address, and forces it to be sent to the target satellite modem through the target LAN's Layer 2 network interface in the forwarding state.

[0043] For example, the address resolution protocol information is sent to the corresponding satellite via the target satellite modem to refresh the address resolution protocol in the target satellite modem's local and satellite gateways, and refresh the FDB table in the data link layer of the target satellite modem. This restores the uplink connectivity from the terminal to the master station (i.e., the satellite corresponding to the target satellite modem) within milliseconds, and causes the downlink return packets of the master station to be rerouted through the target modem to reach the terminal device, thus achieving two-way lossless connectivity.

[0044] S260. If the external switching command instructs the switching of the satellite communication link in the network layer, then the three-layer target link switching operation is performed in the network layer through the main control circuit board.

[0045] The technical solution of this invention involves obtaining an external switching command through the main control circuit board. This external switching command includes an instruction to switch satellite communication links between different satellite modems in the data link layer or the network layer. The satellite communication link includes the communication link between the terminal device, the satellite modem, and the satellite corresponding to the satellite modem. If the external switching command instructs to switch the satellite communication link in the data link layer, then the target LAN-side Layer 2 port corresponding to the target Layer 2 link and the original LAN-side Layer 2 port corresponding to the original Layer 2 link are determined. The original LAN-side Layer 2 port and the target LAN-side Layer 2 port are configured through the Ethernet chip. The system configures the state of the Layer 2 network port on the LAN side, including states indicating that the connection between the terminal device and the satellite modem in the original Layer 2 link is blocked, and the connection between the terminal device and the satellite modem in the target Layer 2 link is enabled; the address mapping table associated with the original LAN side Layer 2 network port and the Layer 2 interface in the Ethernet switching chip is cleared; address resolution protocol information, including the address of the terminal device, is sent to the corresponding satellite modem through the target LAN side Layer 2 network port; if the external switching command indicates that the satellite communication link is switched in the network layer, then the Layer 3 target link switching operation is performed in the network layer through the main control circuit board. This embodiment of the invention, by configuring the states of the original LAN side Layer 2 network port and the target LAN side Layer 2 network port, achieves Layer 2 target link switching by only changing the logical states of the original LAN side Layer 2 network port and the target LAN side Layer 2 network port without closing the LAN side Layer 2 network port. This avoids service interruption during satellite communication link switching in the data link layer and improves the switching efficiency of the satellite communication link.

[0046] In one embodiment, configuring the status of the local area network (LAN) side Layer 2 port corresponding to the original Layer 2 link and the target LAN side Layer 2 port via the Ethernet chip includes: Write the corresponding fields into the register of the Ethernet switching chip to configure the original LAN-side Layer 2 port in blocking mode and the target LAN-side Layer 2 port in forwarding mode.

[0047] In this embodiment, the blocking state can refer to a state in which the original LAN-side Layer 2 network port logically stops forwarding messages to the corresponding satellite modem. The blocking state does not power down the original LAN-side Layer 2 network port. The blocking state can be a Block / Disabled state. The forwarding state can refer to a state in which the target LAN-side Layer 2 network port logically allows forwarding of messages to the target satellite modem. The forwarding state can be a Forwarding state.

[0048] Specifically, the CPU writes a control word to the control register of the Ethernet switching chip via the bus, configuring the original LAN-side Layer 2 port to a blocking state. At this time, the Ethernet switching chip stops forwarding data to the original LAN-side Layer 2 port, and any received data link layer packets are directly discarded. The CPU also writes a control word to the control register of the Ethernet switching chip via the bus, configuring the target LAN-side Layer 2 port to a forwarding state. At this time, unicast and broadcast packet forwarding is allowed through the target LAN-side Layer 2 port.

[0049] In one example Figure 3 This is a flowchart of a multi-link switching control method in the data link layer provided by an embodiment of the present invention. Figure 3 As shown, the method includes: receiving an external switching command instructing a satellite communication link switch at the data link layer; keeping the original LAN-side Layer 2 port (LAN1), the target LAN-side Layer 2 port (LAN2), and the Layer 2 interface (LAN4) powered on (i.e., normally open); the CPU writes a control word to the register inside the Ethernet switching chip; by setting the state of LAN1 to Block, the original Layer 2 link is blocked; by setting the state of LAN2 to Forward, the target Layer 2 link is enabled. After the state settings are completed, the CPU forcibly clears the address mapping table; the CPU constructs a gratuitous ARP broadcast packet (i.e., address resolution protocol information) with the source MAC address being the MAC address of the terminal device and the source IP address being the IP address of the terminal device by listening to or reading the MAC address of the terminal device; and sends it to the target satellite modem through the target LAN-side Layer 2 port.

[0050] Example 3 Figure 4 This is a flowchart of a multi-link switching control method provided in Embodiment 3 of the present invention. This embodiment is an optimization based on any of the above embodiments, and mainly includes a detailed description of the process of performing a three-layer target link switching operation. It should be noted that technical details not described in detail in this embodiment can be found in any of the above embodiments. Figure 4 As shown, the method includes: S410. Obtain an external switching command through the main control circuit board. The external switching command includes an instruction to switch the satellite communication links of different satellite modems in the data link layer or the network layer. The satellite communication link includes the communication link between the terminal device, the satellite modem, and the satellite corresponding to the satellite modem.

[0051] S420. If the external switching command instructs the switching of the satellite communication link in the data link layer, then the main control circuit board performs a Layer 2 target link switching operation in the data link layer and ends the execution.

[0052] S430. If the external switching instruction indicates that the satellite communication link is switched in the network layer, then the set time range, the target WAN-side Layer 3 network port corresponding to the Layer 3 target link, and the original WAN-side Layer 3 network port corresponding to the original Layer 3 link are determined.

[0053] In this embodiment, the target WAN-side Layer 3 port can be the WAN-side Layer 3 port that establishes a connection with the target satellite modem in the target Layer 3 target link. The original WAN-side Layer 3 port can be the WAN-side Layer 3 port that establishes a connection with the switched satellite modem in the original Layer 3 link.

[0054] Specifically, if an external handover command instructs the switching of the satellite communication link in the network layer, a set time range is determined, the target WAN-side Layer 3 network port is determined according to the target link identifier in the external handover command, and the original WAN-side Layer 3 network port is determined according to the status of the WAN-side Layer 3 network port.

[0055] S440. Disconnect the logical bridge path between the original WAN-side Layer 3 port and the Layer 3 interface in the Ethernet switching chip, and disconnect the physical connection between the Layer 3 interface and the terminal device.

[0056] In this embodiment, the logical bridging path can be a logical path within the Ethernet switching chip that connects the Layer 3 interface to the Layer 3 port on the WAN side at the network layer. The physical connection can include the physically connected state between the Layer 3 interface and the terminal device. A physical connection can be manifested as the Layer 3 interface being powered on.

[0057] Specifically, the CPU decouples the Layer 3 interface from the original WAN-side Layer 3 port via the internal bridge of the Ethernet switching chip. The CPU then powers off the Layer 3 interface to disconnect the physical connection between the Layer 3 interface and the terminal device.

[0058] S450. Based on the set time range, establish a logical bridge path between the target WAN side Layer 3 port and the Layer 3 interface in the Ethernet switching chip, and restore the physical connection between the Layer 3 interface and the terminal device.

[0059] Specifically, by ensuring that the physical connection between the Layer 3 interface and the terminal device is disconnected within a set time range, the terminal device is prevented from failing to recognize the interruption of the satellite communication link, thus prompting the terminal device to actively trigger an IP address update. Specifically, a timer begins after the physical connection is disconnected. Within the set time range, a logical bridge path is established within the Ethernet switching chip between the target WAN-side Layer 3 port and the Layer 3 interface, restoring power to the Layer 3 interface.

[0060] For example, after powering on the Layer 3 interface, the terminal device detects a signal indicating that the physical connection has been restored. The network manager of the terminal system immediately forcibly clears the IP address cache of the local network card and sends a broadcast packet containing a Dynamic Host Configuration Protocol Discover (DHCPDiscover) message within milliseconds. Since the logical bridge path between the Layer 3 network port and the Layer 3 interface on the target WAN side is now connected, the DHCP Discover broadcast packet is transmitted to the target satellite modem through the Layer 3 network port on the target WAN side. The target satellite modem (or the DHCP server of the satellite master station) returns a DHCP Offer message, and the terminal successfully obtains the IP address of the target satellite modem within 1-2 seconds.

[0061] The technical solution of this invention involves obtaining an external switching instruction through the main control circuit board. This external switching instruction includes an instruction to switch satellite communication links between different satellite modems in the data link layer or the network layer. The satellite communication link includes the communication link between the terminal device, the satellite modem, and the satellite corresponding to the satellite modem. If the external switching instruction indicates switching the satellite communication link in the data link layer, then the main control circuit board performs a Layer 2 target link switching operation in the data link layer. If the external switching instruction indicates switching the satellite communication link in the network layer, then the set time range, the target WAN-side Layer 3 port corresponding to the Layer 3 target link, and the original WAN-side Layer 3 port corresponding to the original Layer 3 link are determined. The logical bridging path between the original WAN-side Layer 3 port and the Layer 3 interface in the Ethernet switching chip is released, and the physical connection between the Layer 3 interface and the terminal device is released. Based on the set time range, a logical bridging path is established between the target WAN-side Layer 3 port and the Layer 3 interface in the Ethernet switching chip, and the physical connection between the Layer 3 interface and the terminal device is restored. The technical solution of this invention restores the physical connection between the Layer 3 interface and the terminal device based on the set time range, ensuring that the physical connection disconnection time is within the set time range. This ensures that the terminal device can recognize the satellite communication link disconnection while accelerating network recovery and reducing the impact on services.

[0062] In one embodiment, the main control circuit board further includes a first physical layer chip corresponding to the three-layer interface. The first physical layer chip includes a power-down state and a power-on state, and the power-down state and the power-on state are configured by registers in the first physical layer chip. When the first physical layer chip is in the power-down state, the physical connection between the three-layer interface and the terminal device is disconnected; When the first physical layer chip is in the power-on state, the physical connection between the three-layer interface and the terminal device is restored.

[0063] In this embodiment, the first physical layer chip can be the physical layer (PHY) chip corresponding to the Layer 3 interface. By powering on or off the first physical layer chip, the physical connection of the Layer 3 interface can be managed. The power-off state can be the state where the first physical layer chip is powered off. When the first physical layer chip is in the power-off state, the Layer 3 interface is not working, and the physical connection between the Layer 3 interface and the terminal device is disconnected. The power-on state can be the state where the first physical layer chip is powered on. When the first physical layer chip is in the power-on state, the Layer 3 interface normally performs message sending and receiving, and a physical connection exists between the Layer 3 interface and the terminal device.

[0064] Specifically, the CPU writes control words to the control register of the first physical layer chip corresponding to the three-layer interface in the Ethernet switching chip, thereby managing the power-down and power-on states of the first physical layer chip.

[0065] In one embodiment, the set time range includes a lower time limit and an upper time limit, wherein the lower time limit is less than the upper time limit. The step of establishing a logical bridging path between the target WAN-side Layer 3 port and the Layer 3 interface in the Ethernet switching chip based on the set time range, and restoring the physical connection between the Layer 3 interface and the terminal device, includes: S4501. Determine the blocking time, wherein the blocking time is less than the upper limit time and greater than the lower limit time.

[0066] In this embodiment, the blocking time can be the delay for restoring the physical connection. After the physical connection is broken, a timer is started, and the physical connection is restored after the blocking time. The lower limit time can be the lower limit of a set time range. If the disconnection time of the physical connection between the Layer 3 interface and the terminal device is less than the lower limit time, the jitter cancellation mechanism of the terminal device may filter the signal of the physical connection disconnection, and the terminal device will not actively update its IP address. The upper limit time can be the upper limit of a set time range. If the disconnection time of the physical connection between the Layer 3 interface and the terminal device is greater than the upper limit time, it prolongs unnecessary network interruption time, affecting services.

[0067] Specifically, the blocking time can be determined based on experience or historical data; this invention does not impose any limitations on this.

[0068] S4502. During the blocking time, establish a logical bridge path between the target WAN side Layer 3 port and the Layer 3 interface in the Ethernet switching chip.

[0069] Specifically, after the physical connection is broken, a timer is started. In order to make full use of the time delay for restoring the physical connection, the logical bridge path between the target WAN side Layer 3 port and Layer 3 interface inside the Ethernet switching chip can be restored first during the blocking time.

[0070] S4503. Within the time limit from the blocking time to the upper limit, restore the physical connection between the Layer 3 interface and the terminal device.

[0071] Specifically, within the maximum time limit after the blocking period, the physical connection between the Layer 3 interface and the terminal device is restored to ensure that the terminal device can recognize the satellite communication link being disconnected, thereby accelerating network recovery and reducing the impact on services.

[0072] In one example Figure 5 This is a flowchart of a multi-link switching control method in the network layer provided by an embodiment of the present invention. Figure 5 As shown, the method includes: when receiving an external switching command indicating a satellite communication link switch at the network layer, the logical bridge path between the original WAN-side Layer 3 port (denoted as WAN1) and the Layer 3 interface (denoted as LAN3) inside the Ethernet switching chip is released; the CPU controls the first physical layer chip corresponding to the Layer 3 interface to power down; within a set time range, a blocking time is determined; during the blocking time, a logical bridge path is established between the target WAN-side Layer 3 port (denoted as WAN2) and the Layer 3 interface inside the Ethernet switching chip; after the blocking time ends, the first physical chip in the Layer 3 interface is powered on again; the terminal device detects the restoration of the Layer 3 interface level and sends a DHCP Discover broadcast packet to the target WAN-side Layer 3 port through the Layer 3 interface; after receiving the broadcast packet, the target satellite modem or satellite returns information including a DHCP response, enabling the terminal device to obtain the IP address of the target satellite modem.

[0073] Example 4 Figure 6 This is a schematic diagram of a multi-link switching control device provided in Embodiment 4 of the present invention. Figure 6 As shown, the device includes: The device includes at least two WAN-side Layer 3 ports 610, at least two LAN-side Layer 2 ports 620, a Layer 3 interface 630, a Layer 2 interface 640, a main control circuit board 650, and a housing 660. The main control circuit board 650 includes a central processing unit and an Ethernet switching chip. The Ethernet switching chip includes registers. The Layer 3 interface and the Layer 2 interface are used to connect to external terminal devices of the multi-link switching control device. The main control circuit board 650 is connected to the WAN-side Layer 3 network port 610, the LAN-side Layer 2 network port 620, the Layer 3 interface 630, and the Layer 2 interface 640. It is used to obtain external switching instructions. If the external switching instruction indicates that the satellite communication link should be switched in the data link layer, then a Layer 2 target link switching operation is performed in the data link layer. If the external switching instruction indicates that the satellite communication link should be switched in the network layer, then a Layer 3 target link switching operation is performed in the network layer. The Layer 2 target link switching operation includes, in the data link layer, configuring the local area network side Layer 2 port 620, and switching the satellite communication link from the original Layer 2 link to the Layer 2 target link without closing the local area network side Layer 2 port 620; The three-layer target link switching operation includes, in the network layer, configuring the WAN-side three-layer network port 610 and three-layer interface 630, and based on a set time range, switching the satellite communication link from the original three-layer link to the three-layer target link.

[0074] Specifically, the multi-link switching control device consists of at least two WAN-side Layer 3 ports 610, at least two LAN-side Layer 2 ports 620, a Layer 3 interface 630, a Layer 2 interface 640, a main control circuit board 650, and a housing 660. The main control circuit board 650 houses a CPU and an Ethernet switching chip, which are connected via a bus. The housing 660 exposes at least two sets of WAN-side Layer 3 ports 610 for connecting satellite modems, at least two sets of LAN-side Layer 2 ports 620, and Layer 3 interfaces 630 and Layer 2 interfaces 640 for connecting terminal devices. The main control circuit board 650 is connected to the WAN-side Layer 3 ports 610, the LAN-side Layer 2 ports 620, the Layer 3 interface 630, and the Layer 2 interface 640 via a bus.

[0075] For example, the CPU can also bring out a serial port and a set of GPIO pins to communicate with the main control unit of an external vehicle or cabin to receive external switching commands.

[0076] The main control circuit board 650 can receive external switching commands. The CPU in the main control circuit board 650 can perform a Layer 2 target link switching operation in the data link layer without shutting down the Layer 2 network port 620 on the local area network side. In the network layer, it can perform a Layer 3 target link switching operation based on a set time range.

[0077] The technical solution of this invention involves connecting a main control circuit board 650 to a WAN-side Layer 3 port 610, a LAN-side Layer 2 port 620, a Layer 3 interface 630, and a Layer 2 interface 640. This connection is used to acquire external switching commands. If the external switching command instructs the switching of the satellite communication link at the data link layer, a Layer 2 target link switching operation is performed at the data link layer. If the external switching command instructs the switching of the satellite communication link at the network layer, a Layer 3 target link switching operation is performed at the network layer. The Layer 2 target link switching operation includes, at the data link layer, configuring the LAN-side Layer 2 port 620 to switch the satellite communication link from the original Layer 2 link to the target Layer 2 link without closing the LAN-side Layer 2 port 620. The Layer 3 target link switching operation includes, at the network layer, configuring the WAN-side Layer 3 port 610 and the Layer 3 interface 630 to switch the satellite communication link from the original Layer 3 link to the target Layer 3 link based on a set time range. The technical solution of this invention ensures that the Layer 2 network port 620 on the local area network side remains open during the Layer 2 target link switching operation, thus avoiding service interruption during satellite communication link switching at the data link layer. By setting a time range for the Layer 3 target link switching operation, it ensures that the terminal device recognizes the disconnected state of the original Layer 3 link and triggers the reconnection mechanism to actively update the IP address. This also ensures that the reconnection time of the Layer 3 target link does not exceed the set time range, reducing network interruption time.

[0078] In one embodiment, the WAN-side Layer 3 port includes a first Layer 3 port and a second Layer 3 port, and the LAN-side Layer 2 port includes a first Layer 2 port and a second Layer 2 port. The first Layer 3 port, the second Layer 3 port, the first Layer 2 port, and the second Layer 2 port are used to establish a connection with the corresponding satellite modem. The first Layer 3 port, the second Layer 3 port, the first Layer 2 port, the second Layer 2 port, the Layer 3 interface, and the Layer 2 interface are connected to the corresponding pins of the Ethernet switching chip.

[0079] In this embodiment, the first and second layer 3 network ports are network ports in the network layer used to establish connections with different satellite modems. The naming of the first and second layer 3 network ports in this invention is for differentiation only and does not impose other restrictions. The first and second layer 2 network ports are network ports in the data link layer used to establish connections with different satellite modems. The naming of the first and second layer 2 network ports in this invention is for differentiation only and does not impose other restrictions.

[0080] Specifically, the WAN-side Layer 3 port and the LAN-side Layer 2 port each include two ports for establishing connections with different satellite modems. Each WAN-side Layer 3 port, each LAN-side Layer 2 port, the Layer 3 interface, and the Layer 2 interface are connected to the corresponding pins of the Ethernet switching chip.

[0081] In one embodiment, the main control circuit board further includes the local area network side Layer 2 port and the second physical layer chip corresponding to the Layer 2 interface. The second physical layer chip is in working state during the execution of the Layer 2 target link switching operation. The second physical layer chip is used to maintain the open state of the local area network side Layer 2 port.

[0082] In this embodiment, the second physical layer chip can be the physical layer chip corresponding to the local area network side Layer 2 port and Layer 2 interface in the Ethernet switching chip.

[0083] Specifically, by keeping the second physical layer chip in a normally powered physical working (Link Up) state, the second layer network port on the local area network side is kept open.

[0084] In one example Figure 7 This is a schematic diagram illustrating an application scenario of a multi-link switching control device provided in an embodiment of the present invention. In the multi-link switching control device, the WAN-side Layer 3 network ports include a first Layer 3 network port (WAN1) and a second Layer 3 network port (WAM2), the LAN-side Layer 2 network ports include a first Layer 2 network port (LAN1) and a second Layer 2 network port (LAN2), and also include a Layer 3 interface (LAN3) and a Layer 2 interface (LAN4), as well as expansion interfaces LAN5 and LAN6. WAN1 and WAM2 are used to establish a connection with the first satellite modem (MODEM1) at the network layer (L3), LAN1 and LAN2 are used to establish a connection with the second satellite modem (MODEM2) at the data link layer (L2), LAN3 is used to establish a connection with the terminal device at the network layer, and LAN4 is used to establish a connection with the terminal device at the data link layer. Inside the Ethernet switching chip (not shown in the diagram), a logical bridge path (path A) can be established between WAN1 and LAN3, and a logical bridge path (path B) can also be established between WAN2 and LAN3. The network segment between MODEM1 and WAN1 can be denoted as network segment A, the network segment between MODEM2 and WAN2 can be denoted as network segment B, and the network segment between LAN3 and the terminal device can be denoted as network segment C. The multi-link switching control device can switch satellite communication links according to the received external switching commands.

[0085] The multi-link switching control device provided in this embodiment of the invention can execute a multi-link switching control method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0086] The present invention will be described by way of example below: This invention belongs to the fields of satellite communication technology and computer network technology, specifically relating to a control method and integrated hardware device for achieving millisecond-level or second-level lossless link switching in satellite communication scenarios, while simultaneously supporting Layer 2 (data link layer, denoted as L2) and Layer 3 (network layer, denoted as L3) services. In mobile satellite communication or high-reliability assurance scenarios for critical services, dual-satellite modem hot backup is a common redundancy deployment method. Modems typically provide both Layer 2 (L2 bridging) and Layer 3 (L3 routing) network interfaces to meet the access requirements of different terminals and services.

[0087] Existing technologies have the following insurmountable technical drawbacks when performing redundant link switching: 1. Inadequate Layer 2 switching mechanism: Traditional Layer 2 link switching is achieved directly by shutting down the old network port (Down) and opening the new network port (Up). However, the Ethernet physical layer (PHY chip) needs to perform rate auto-negotiation and link training after power-on, a process that typically takes 1-3 seconds, resulting in second-level service interruptions and failing to meet the seamless switching requirements of real-time services such as voice and video. If the physical link is always open and switching is only done through logical bridges, the MAC address mapping entries of the old ports in the forwarding tables (FDB) of the bridge and upstream switching devices cannot be automatically and promptly cleared. This leads to downlink data packets still being sent to the blocked old path during the forwarding table aging time (usually 300 seconds), creating a serious communication black hole.

[0088] 2. Layer 3 mode switching mechanism impacts performance: Traditional routers use Network Address Translation (NAT) to switch between WAN1 and WAN2, which leads to multiple NATs. Satellite communication commonly uses Transmission Control Protocol (TCP) acceleration technology, and Performance Enhancing Proxy (PEP) technology requires that the Internet Protocol (IP) header of the communication flow cannot be tampered with. The presence of multiple NATs will cause satellite PEP acceleration to fail, resulting in a sharp drop in TCP throughput under high-latency satellite links. If a NAT-free Layer 3 bridging switch is used, after switching to a new modem, the terminal device (acting as a Dynamic Host Configuration Protocol (DHCP) client) is completely unaware of the change in the physical link. Since its DHCP lease has not yet expired, the terminal will not actively initiate an IP address update, causing the terminal to use the old network segment IP for a long time, resulting in communication interruption.

[0089] Therefore, there is an urgent need for an intelligent routing control solution that can effectively balance Layer 2 and Layer 3 services, avoid the impact of NAT on satellite acceleration, and achieve highly reliable and fast failover.

[0090] The purpose of this invention is to provide a Layer 2 and Layer 3 multi-link switching control method and device for integrated satellite communication intelligent routing equipment, which aims to solve the problems of delayed physical auto-negotiation and communication black holes caused by MAC entry residues during Layer 2 switching, as well as the problems of NAT disrupting satellite PEP acceleration and the inability of terminals to update their IP addresses in real time when there is no NAT during Layer 3 switching.

[0091] In one embodiment, the present invention provides an integrated hardware device that accommodates rapid switching between Layer 2 and Layer 3 services, comprising: The housing and the main control circuit board disposed inside the housing; The main control circuit board integrates a main control CPU and an industrial-grade Ethernet switching chip connected to the main control CPU via a high-speed bus. The outer casing panel exposes two sets of wide area network (WAN) side Layer 3 ports (WAN1, WAN2) and local area network (LAN) side Layer 2 ports (LAN1, LAN2) for connecting the satellite modem, as well as a Layer 3 interface (LAN3) and a Layer 2 interface (LAN4) for connecting user terminal equipment.

[0092] In one embodiment, the present invention also provides a Layer 2 / 3 multi-link switching control method based on the above-described device, comprising the following steps: Step 1: Receive external handover instructions, including: The main control CPU receives switching commands (i.e., external switching commands) sent by the external main control unit in real time through the hardware control interface (General-Purpose Input / Output (GPIO) level signals, serial port AT (Attention Command) commands, or network control messages). The external switching command includes a network mode identifier (L2 or L3) and a target link identifier (Modem1 (i.e., the original Layer 2 link including the satellite modem designated as Modem1) or Modem2 (i.e., the target Layer 2 link including the satellite modem designated as Modem2)).

[0093] Step 2: Execute Layer 2 switchover control logic (i.e., execute Layer 2 target link switching operation), including: If the network mode is identified as Layer 2 (L2) and the target link is identified as switching from Modem1 to Modem2, the main control CPU controls the Ethernet switching chip to execute the following mutual exclusion switching sequence: 1. Physical link always open: Keep the physical layer (PHY) chips (i.e., the second physical layer chips) corresponding to LAN1 (Modem1 L2 port), LAN2 (Modem2 L2 port) and LAN4 (terminal (i.e. terminal device) L2 port) in the physical working (link up) state (i.e., in working state). 2. Channel State Replacement: Change the register state of the Ethernet switching chip, configure the forwarding state of LAN1 to "Block / Disabled" (i.e., blocking state), and configure the forwarding state of LAN2 to "Forward" (i.e., forwarding state). 3. Forwarding table synchronous refresh (FDB Flush): At the same time as the channel state replacement is completed, the main control CPU (i.e., CPU) sends a hardware entry cleanup command to the Ethernet switching chip, instantly and forcibly emptying all Media Access Control (MAC) address mapping entries (i.e., address mapping table) (Filtering Database (FDB) table) associated with LAN1 and LAN4 in the switching chip. 4. Free Address Resolution Protocol (ARP) Proxy Injection: The main control CPU listens to or reads the MAC address of the terminal device, constructs a free ARP broadcast packet (i.e., address resolution protocol information) with the source MAC address being the terminal device's MAC address and the source IP address being the terminal device's IP address, and forces it to be sent to Modem2 through the LAN2 interface in forwarding state, so as to refresh the ARP and Layer 2 forwarding tables of Modem2 and the satellite master station gateway, and realize millisecond-level one-way and two-way communication.

[0094] Step 3: Execute the three-layer switchover control logic, including: If the network mode is identified as Layer 3 (L3), and the target link is identified as switching from Modem1 (i.e., the original Layer 3 link including the satellite modem designated as Modem1) to Modem2 (i.e., the target Layer 3 link including the satellite modem designated as Modem2), the main control CPU executes the following NAT-free bridging switchover timing sequence: 1. Remove the old bridge: Disconnect the logical bridge between LAN3 and WAN1 inside the Ethernet switching chip; 2. Control terminal interface physical interruption: The main control CPU forcibly sets the physical layer status of LAN3, which is directly connected to the terminal device, to "physical disconnect (Down)" through the configuration register, and maintains it for a set time blocking threshold t_1 (i.e. blocking time). Furthermore, the set time blocking threshold t_1 has a range of 1.0s (lower limit time) ≤ t_1 ≤ 2.0s (upper limit time). The reason for setting this threshold is that if t_1 < 1.0s, the network card debouncing mechanism of the terminal device's operating system may filter the disconnection signal, resulting in the inability to trigger DHCP re-application; if t_1 > 2.0s, it will prolong the unnecessary network interruption time.

[0095] 3. Establish a new bridge: During time t_1, the main control CPU controls the Ethernet switching chip to establish a logical bridge path between LAN3 and WAN2, so that LAN3 and WAN2 are in the same broadcast domain; 4. Restore the physical connection of the terminal interface: After the t_1 delay ends, the main control CPU restores the physical layer state of LAN3 to "physical connection (Up)"; 5. Triggering Fast DHCP: The terminal device's network card detects that the physical link has experienced an explicit physical interruption, forces its local network protocol stack to clear the current IP address lease, and immediately sends a DHCPDiscover message from LAN3 to WAN2, thereby obtaining the Layer 3 network IP corresponding to Modem2 in a very short time.

[0096] The present invention has the following significant beneficial effects: Layer 2 switchover time has been reduced to the millisecond level. By keeping the physical layer always open, the logical "Forward / Block" mechanism avoids the approximately 2-second auto-negotiation delay of the Ethernet PHY chip. At the same time, the communication black hole problem in Layer 2 switching is solved through the linkage of "FDB Flush + gratuitous ARP proxy injection", keeping the switchover time within 50ms.

[0097] Layer 3 NAT-free switching compatible with satellite PEP acceleration. It fully utilizes bridging and pass-through, with the WAN and LAN ports not acting as gateways, eliminating the disruption to the satellite PEP acceleration mechanism caused by multiple NAT layers.

[0098] This solution addresses the challenge of updating terminal IP addresses under Layer 3 bridging. A physical interruption mechanism with a duration of 1.0s ≤ t_1 ≤ 2.0s enables the terminal operating system to recognize the link disconnection and trigger a reconnection mechanism. This allows the terminal to reacquire a new network segment IP address within seconds of the link switch, ensuring the practicality of Layer 3 NAT-free switching.

[0099] In one example, a multi-link switching control device comprises: a main control CPU (using a quad-core processor running a customized embedded Linux system), an Ethernet switching chip (using a gigabit switching chip with a hardware virtual local area network (VLAN) engine), and a physical layer PHY chip.

[0100] The terminal-side network ports (LAN3, LAN4) and the modem-side network ports (WAN1, WAN2, LAN1, LAN2) are all directly connected to the corresponding pins of the switching chip.

[0101] The main control CPU and the switching chip exchange data through the Reduced Gigabit Media Independent Interface (RGMII) bus, and at the same time control the reading and writing of its internal registers through the Management Data Input / Output (MDIO) bus.

[0102] The main control CPU has a serial port and a set of GPIO pins to communicate with the main control unit of an external vehicle or cabin to receive switching commands.

[0103] In one example, the multi-link switching control method in the data link layer includes: 1. Switchover command detected (i.e., external switching command): The main control CPU receives a control message from the external main control unit indicating "Layer 2 switch to Modem2". At this time, both LAN1 (connected to Modem1) and LAN2 (connected to Modem2) are physically in the Up state and are in normal power-on handshake state.

[0104] 2. Write to the port status register (i.e., the register of the Ethernet switching chip): The main control CPU writes control words to the control register of the switching chip via the MDIO bus to configure port filtering mapping: When LAN1 is set to Disabled / Blocking state (i.e., blocked state), the hardware forwarding engine inside the switching chip stops forwarding data to the LAN1 port, and any received Layer 2 packets are directly discarded.

[0105] Set LAN2 to Forwarding state to allow it to forward unicast and broadcast packets.

[0106] 3. Hardware FDB table (i.e., address mapping table) instantaneous clearing (FDB Flush): While writing to the port status register, the main control CPU writes a clear instruction to the address resolution register of the switching chip: by clearing the bridge FDB table, the switching chip is forced to clear the historical MAC address learning records for LAN1, so that packets sent by subsequent terminals (LAN4) can be immediately broadcast and relearned on the newly enabled LAN2 port, avoiding traffic loss due to incorrect MAC address pointing.

[0107] 4. Gratuitous ARP Proxy Injection: To accelerate network convergence, especially to shorten the time it takes for the upstream satellite master station gateway to learn new paths, the main control CPU extracts the MAC address and IP address of the connected terminal (LAN4) from the system cache. The main control CPU's software module constructs a standard gratuitous ARP data frame in memory through the underlying raw socket, such as: Source MAC / Destination MAC: 00:11:22:33:44:55 / FF:FF:FF:FF:FF:FF Source IP / Destination IP: 10.10.10.100 / 10.10.10.100 ARPOpcode: 0x0001 (Request) The main control CPU, through the internal management port of the switching chip, forces the gratuitous ARP frame to be sent from the newly enabled LAN2 port towards Modem2. Upon receiving the frame, Modem2 instantly updates its internal switch and the forwarding tables of the remote satellite master station, binding the outgoing port at 00:11:22:33:44:55 to the satellite channel pointing to Modem2. This mechanism solves the serious technical defect that prevents downlink data from flowing to new paths when the terminal is in a silent state (not actively sending packets), truly achieving millisecond-level bidirectional communication.

[0108] In one example, the multi-link switching control method in the network layer includes: 1. Logical Link (i.e., logical communication link) release: A multi-link switching control device operates in a NAT-free Layer 3 mode, with WAN1 and WAN2 directly bridged to LAN3. Upon receiving an external switching command to "switch to Modem2", the main control CPU first releases the bridge from the physical WAN1 interface. At this point, the Layer 3 logical path between the terminal and Modem1 is severed.

[0109] 2. Controlling the LAN3 physical interface to interrupt: In order to force the terminal (connected via LAN3) to reacquire IP, the main control CPU writes a control word to the PHY control register of the corresponding LAN3 in the switching chip (i.e., the register of the first physical layer chip) (for example, writing the 11th bit of the BMCR register via MDIO) to configure it to the Power Down state.

[0110] The main control CPU starts a high-precision timer to delay the start time.

[0111] The blocking time t_1 is set as follows: system delay t_1 = 1.5 seconds. In Windows, Linux, and various embedded real-time operating systems, network card drivers typically employ a jitter filtering algorithm of approximately 1 second to prevent repeated protocol stack resets caused by momentary network interruptions due to physical vibrations. Therefore, this invention, through extensive experimentation, demonstrates that setting t_1 to 1.5 seconds ensures 100% that the terminal's operating system recognizes the hardware event that "the network cable has been unplugged."

[0112] 3. Establishing a new bridging path: During the t_1 delay, the main control CPU binds the Layer 2 and Layer 3 network interfaces (WAN2, connected to Modem2) to the bridge. At this time, LAN3 and WAN2 are logically in the same virtual bridge / Layer 2 broadcast domain, but because LAN3 is physically in the Down state, data flow has not yet been enabled.

[0113] 4. Restore physical connection and trigger terminal DHCP: After the delay t_1=1.5 seconds, the main control CPU writes the control word to the control register of the PHY chip corresponding to LAN3 again to restore its normal power-on operation (Power Up / Link Up).

[0114] Subsequently, the terminal detected a physical layer link recovery signal; the terminal's network manager immediately forcibly cleared the local network card's IP address cache and sent a DHCP Discover broadcast packet outward within milliseconds; since LAN3 and WAN2 were already bridged at this time, the DHCP Discover broadcast packet was instantly transmitted to Modem2 through WAN2; Modem2 (or the satellite master station's DHCP server) returned a DHCP Offer, and the terminal successfully obtained a new IP address in network segment B within 1-2 seconds.

[0115] The entire Layer 3 target link switching process not only completely avoids multiple NATs (thus ensuring the normal operation of the satellite PEP acceleration mechanism), but also shortens the Layer 3 switchover recovery time, which could have taken several hours (depending on the DHCP lease period), to less than 3 seconds through a precise t_1 physical interruption mechanism.

[0116] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0117] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A multi-link switching control method, characterized in that, An application is made to a multi-link switching control device, the multi-link switching control device comprising: at least two WAN-side Layer 3 ports, at least two LAN-side Layer 2 ports, a Layer 3 interface, a Layer 2 interface, a main control circuit board, and a housing. The main control circuit board includes a central processing unit (CPU) and an Ethernet switching chip. The Ethernet switching chip includes registers. The Layer 3 interface and the Layer 2 interface are used to connect to external terminal devices of the multi-link switching control device. The method includes: The main control circuit board obtains external switching instructions, which include instructions in the data link layer or the network layer to switch satellite communication links of different satellite modems. The satellite communication links include the communication links between the terminal device, the satellite modem, and the satellites corresponding to the satellite modem. If the external switching command instructs the switching of the satellite communication link in the data link layer, then the main control circuit board performs a Layer 2 target link switching operation in the data link layer. If the external switching command instructs the switching of the satellite communication link in the network layer, then the three-layer target link switching operation is performed in the network layer through the main control circuit board; The Layer 2 target link switching operation includes, in the data link layer, configuring the local area network side Layer 2 port to switch the satellite communication link from the original Layer 2 link to the Layer 2 target link without closing the local area network side Layer 2 port; The three-layer target link switching operation includes, in the network layer, configuring the WAN-side three-layer network port and the three-layer interface, and based on a set time range, switching the satellite communication link from the original three-layer link to the three-layer target link.

2. The method according to claim 1, characterized in that, The external switching instruction includes a network mode identifier and a target link identifier. The network mode identifier includes an identifier indicating the data link layer or the network layer, and the target link identifier indicates a satellite communication link including a target satellite modem.

3. The method according to claim 1, characterized in that, If the external handover command instructs a handover of the satellite communication link at the data link layer, then the main control circuit board performs a Layer 2 target link handover operation at the data link layer, including: If the external switching instruction indicates that the satellite communication link is switched in the data link layer, then the target local area network side Layer 2 port corresponding to the Layer 2 target link and the original local area network side Layer 2 port corresponding to the original Layer 2 link are determined. The Ethernet chip is used to configure the status of the original LAN-side Layer 2 port and the target LAN-side Layer 2 port. The status includes indicating that the connection between the terminal device and the satellite modem in the original Layer 2 link is blocked, and the connection between the terminal device and the satellite modem in the target Layer 2 link is enabled. Clear the address mapping table in the Ethernet switching chip that is associated with the original LAN side Layer 2 port and the Layer 2 interface; The terminal device sends address resolution protocol information to the corresponding satellite modem through the Layer 2 network port on the target local area network side. The address resolution protocol information includes the address of the terminal device.

4. The method according to claim 3, characterized in that, The configuration of the status of the local area network (LAN) side Layer 2 port corresponding to the original Layer 2 link and the target LAN side Layer 2 port via the Ethernet chip includes: Write the corresponding fields into the register of the Ethernet switching chip to configure the original LAN-side Layer 2 port in blocking mode and the target LAN-side Layer 2 port in forwarding mode.

5. The method according to claim 1, characterized in that, If the external handover command instructs a handover of the satellite communication link in the network layer, then the main control circuit board performs a Layer 3 target link handover operation in the network layer, including: If the external switching instruction indicates that the satellite communication link is switched in the network layer, then the set time range, the target WAN-side Layer 3 network port corresponding to the Layer 3 target link, and the original WAN-side Layer 3 network port corresponding to the original Layer 3 link are determined. Disconnect the logical bridge path between the original WAN-side Layer 3 port and the Layer 3 interface in the Ethernet switching chip, and disconnect the physical connection between the Layer 3 interface and the terminal device; Based on the set time range, a logical bridge path is established between the target WAN-side Layer 3 port and the Layer 3 interface in the Ethernet switching chip, and the physical connection between the Layer 3 interface and the terminal device is restored.

6. The method according to claim 5, characterized in that, The main control circuit board also includes a first physical layer chip corresponding to the three-layer interface. The first physical layer chip includes a power-down state and a power-on state, and the power-down state and the power-on state are configured by registers in the first physical layer chip. When the first physical layer chip is in the power-down state, the physical connection between the three-layer interface and the terminal device is disconnected; When the first physical layer chip is in the power-on state, the physical connection between the three-layer interface and the terminal device is restored.

7. The method according to any one of claims 5-6, characterized in that, The set time range includes a lower time limit and an upper time limit, wherein the lower time limit is less than the upper time limit. Based on the set time range, establishing a logical bridging path between the target WAN-side Layer 3 port and the Layer 3 interface in the Ethernet switching chip, and restoring the physical connection between the Layer 3 interface and the terminal device, includes: The blocking time is determined, wherein the blocking time is less than the upper limit time and greater than the lower limit time; During the blocking time, a logical bridging path is established between the target WAN-side Layer 3 port and the Layer 3 interface in the Ethernet switching chip; Within the time limit from the blocking time to the upper limit, the physical connection between the Layer 3 interface and the terminal device is restored.

8. A multi-link switching control device, characterized in that, include: The device includes at least two WAN-side Layer 3 ports, at least two LAN-side Layer 2 ports, a Layer 3 interface, a Layer 2 interface, a main control circuit board, and a housing. The main control circuit board includes a central processing unit and an Ethernet switching chip. The Ethernet switching chip includes registers. The Layer 3 interface and the Layer 2 interface are used to connect to external terminal devices of the multi-link switching control device. The main control circuit board is connected to the WAN-side Layer 3 network port, the LAN-side Layer 2 network port, the Layer 3 interface, and the Layer 2 interface, and is used to obtain external switching instructions. If the external switching instructions indicate that the satellite communication link should be switched in the data link layer, then the Layer 2 target link switching operation is performed in the data link layer. If the external handover instruction indicates that the satellite communication link should be switched in the network layer, then a three-layer target link handover operation is performed in the network layer. The Layer 2 target link switching operation includes, in the data link layer, configuring the local area network side Layer 2 port to switch the satellite communication link from the original Layer 2 link to the Layer 2 target link without closing the local area network side Layer 2 port; The three-layer target link switching operation includes, in the network layer, configuring the WAN-side three-layer network port and the three-layer interface, and based on a set time range, switching the satellite communication link from the original three-layer link to the three-layer target link.

9. The multi-link switching control device according to claim 8, characterized in that, The WAN-side Layer 3 network port includes a first Layer 3 network port and a second Layer 3 network port, and the LAN-side Layer 2 network port includes a first Layer 2 network port and a second Layer 2 network port. The first Layer 3 network port, the second Layer 3 network port, the first Layer 2 network port, and the second Layer 2 network port are used to establish a connection with the corresponding satellite modem. The first Layer 3 network port, the second Layer 3 network port, the first Layer 2 network port, the second Layer 2 network port, the Layer 3 interface, and the Layer 2 interface are connected to the corresponding pins of the Ethernet switching chip.

10. The multi-link switching control device according to claim 8, characterized in that, The main control circuit board also includes the local area network side Layer 2 port and the second physical layer chip corresponding to the Layer 2 interface. The second physical layer chip is in working state during the execution of the Layer 2 target link switching operation. The second physical layer chip is used to maintain the open state of the local area network side Layer 2 port.

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