A system and method for realizing coordinated disaster recovery of IPv4 Internet dedicated lines

Abstract

The present application provides a system and method for realizing disaster recovery collaboration for an IPv4 Internet dedicated line, wherein: in response to receiving an uplink message from a customer terminal, the CE performs load sharing uplinking by default of equal cost, and the access network and the aggregation switch uplink the uplink message through a Layer 2 VLAN; in response to receiving an uplink message, BAS1 and BAS2 publish a Border Gateway Protocol (BGP) route carrying a load sharing feature to the CR based on whether the load sharing feature is deployed when the BAS publishes the route as a judgment condition; in response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network; in response to receiving the customer service route, the guest BAS places two equal-cost routes matching BAS1 and BS2 in the routing table, and the guest BAS is used to forward the service message to the visitor's network. The present application can effectively realize disaster recovery protection for IPv4 Internet dedicated lines and data center customers.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a system and method for realizing disaster recovery collaboration of an IPv4 Internet dedicated line. Background Art

[0002] Currently, operators can deploy dedicated internet lines based on broadband metropolitan area networks (MANs) or intelligent metropolitan area networks (IMANs) to provide dedicated internet access services to government, enterprise, and data center customers. However, due to the lack of effective protection measures for dedicated internet lines, single-point failures (SPOFs) such as fiber optic cable outages, access line outages, access layer device downtime, aggregation switch downtime, broadband access servers, and service routers can impact services for government, enterprise, and data center customers, leading to communication interruptions for upper-layer applications.

[0003] So far, there is no suitable large-scale deployment method or device to achieve service protection, disaster recovery collaboration, IP address roaming, and seamless migration of government and enterprise customers' Internet dedicated lines and data centers.

[0004] Therefore, how to achieve coordinated disaster recovery of IPv4 Internet dedicated lines has become a breakthrough point for improving the network's digital transformation capabilities. Summary of the Invention

[0005] The technical problem to be solved by this application is to provide an IPv4 Internet dedicated line disaster recovery collaborative implementation system and method to solve the problems existing in the prior art in view of the above-mentioned deficiencies in the prior art.

[0006] In a first aspect, the present application provides an IPv4 Internet dedicated line disaster recovery collaborative implementation system, the system comprising: a customer terminal, a customer edge device CE, an access network, an aggregation switch SW, a broadband access server BAS, a core router CR, and a visitor BAS;

[0007] The client terminal is provided with three layers of CE, and the BAS includes BAS1 and BAS2. The system is used to implement the coordinated disaster recovery process of the IPv4 Internet dedicated line in the uplink direction, wherein:

[0008] In response to receiving uplink messages from client terminals, the CE performs load balancing uplink traffic using equal-cost defaults. The access network and aggregation switches forward the uplink messages through a Layer 2 VLAN.

[0009] In response to receiving the uplink message, BAS1 and BAS2 publish Border Gateway Protocol (BGP) routes with load balancing to the CR, based on whether load balancing is enabled when the BAS advertises the route.

[0010] In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network;

[0011] In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

[0012] In some embodiments, in response to receiving an uplink message, BAS1 and BAS2 publish a Border Gateway Protocol (BGP) route carrying the load balancing feature to the CR based on whether the load balancing feature is deployed when the BAS publishes the route as a judgment condition, specifically including:

[0013] If load balancing is enabled, Border Gateway Protocol (BGP) routes with load balancing are advertised to the CR.

[0014] If the load balancing feature is not deployed, the BAS creates an access control list to match the IPv4 range of the customer dedicated line, prepares a route advertisement policy, and advertises Border Gateway Protocol (BGP) routes with the load balancing feature to the CR.

[0015] In some embodiments, the system is further configured to implement a coordinated disaster recovery implementation process for an IPv4 Internet dedicated line in the downstream direction, wherein:

[0016] In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm;

[0017] In response to receiving the response message, BAS1 or BAS2 sends the response message to the corresponding uplink port of CE according to the static / dynamic routing method;

[0018] In response to receiving the response message, the CE forwards the response message to the client terminal.

[0019] In a second aspect, the present application provides an IPv4 Internet dedicated line disaster recovery collaborative implementation system, the system comprising: a customer terminal, a customer edge device CE, an access network, an aggregation switch SW, a broadband access server BAS, a core router CR, and a visitor BAS;

[0020] The client terminal is provided with a layer 2 CE, the BAS includes BAS1 and BAS2, and the system is used to implement a coordinated disaster recovery process of an IPv4 Internet dedicated line in the uplink direction, wherein:

[0021] In response to the client terminal sending an uplink message, the downlink service sub-interfaces of BAS1 and BAS2 belong to the same Layer 2 Ethernet virtual private network EVPN domain, and BAS1 and BAS2 run the Virtual Router Redundancy Protocol VRRP heartbeat through the Layer 2 EVPN domain;

[0022] Based on whether the BAS is active, VRRP is used as a criterion to send the uplink message to the corresponding BAS;

[0023] Based on whether load balancing is enabled when the BAS advertises routes, it advertises Border Gateway Protocol (BGP) routes with load balancing to the CR.

[0024] In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network;

[0025] In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

[0026] In some embodiments, based on whether the BAS is active, VRRP is used as a judgment condition to send an uplink message to the corresponding BAS, specifically including:

[0027] If BAS1 is the active VRRP, the uplink message is sent to BAS1 via the left link;

[0028] If BAS2 is the active VRRP server, the uplink message is sent to BAS2 via the right link.

[0029] In some embodiments, based on whether the load balancing feature is deployed when the BAS advertises the route, advertising a Border Gateway Protocol (BGP) route with the load balancing feature to the CR specifically includes:

[0030] If load balancing is enabled, Border Gateway Protocol (BGP) routes with load balancing are advertised to the CR.

[0031] If the load balancing feature is not deployed, the BAS creates an access control list to match the IPv4 range of the customer dedicated line, prepares a route advertisement policy, and advertises Border Gateway Protocol (BGP) routes with the load balancing feature to the CR.

[0032] In some embodiments, the system is further configured to implement a coordinated disaster recovery implementation process for an IPv4 Internet dedicated line in the downstream direction, wherein:

[0033] In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm;

[0034] Based on whether the visitor BAS sends the response message to BAS1 or BAS2, the response message is sent to the client terminal through the corresponding BAS.

[0035] In some embodiments, based on whether the visitor BAS sends the response message to BAS1 or BAS2 as a judgment condition, the response message is sent to the client terminal through the corresponding BAS, specifically including:

[0036] If the visitor BAS sends a response message to BAS1, BAS1 sends a downlink message to the client terminal according to the Address Resolution Protocol ARP table entry;

[0037] If the visitor BAS sends a response message to BAS2, BAS2 sends an ARP probe message to the client terminal; in response to receiving the terminal media access control MAC address and Internet Protocol IP address returned by the client terminal based on the ARP probe message, BAS2 establishes a corresponding ARP table entry and sends a downlink message to the client terminal according to the ARP table entry.

[0038] In a third aspect, the present application provides a method for implementing disaster recovery collaboration for an IPv4 Internet dedicated line, wherein a client terminal is provided with a three-layer CE. The method is used to implement a disaster recovery collaboration implementation process for an IPv4 Internet dedicated line in the uplink direction, the method comprising:

[0039] In response to receiving uplink messages from client terminals, the CE performs load balancing uplink traffic using equal-cost defaults. The access network and aggregation switches forward the uplink messages through a Layer 2 VLAN.

[0040] In response to receiving the uplink message, BAS1 and BAS2 publish Border Gateway Protocol (BGP) routes with load balancing to the CR, based on whether load balancing is enabled when the BAS advertises the route.

[0041] In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network;

[0042] In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

[0043] In some embodiments, the method is further used to implement a coordinated disaster recovery implementation process for an IPv4 Internet dedicated line in the downlink direction, and the method further includes:

[0044] In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm;

[0045] In response to receiving the response message, BAS1 or BAS2 sends the response message to the corresponding uplink port of CE according to the static / dynamic routing method;

[0046] In response to receiving the response message, the CE forwards the response message to the client terminal.

[0047] In a fourth aspect, the present application provides a method for implementing disaster recovery collaboration for an IPv4 Internet dedicated line, wherein a client terminal is provided with a Layer 2 CE. The method is used to implement a disaster recovery collaboration implementation process for an IPv4 Internet dedicated line in the uplink direction, and the method comprises:

[0048] In response to the client terminal sending an uplink message, the downlink service sub-interfaces of BAS1 and BAS2 belong to the same Layer 2 Ethernet virtual private network EVPN domain, and BAS1 and BAS2 run the Virtual Router Redundancy Protocol VRRP heartbeat through the Layer 2 EVPN domain;

[0049] Based on whether the BAS is active, VRRP is used as a criterion to send the uplink message to the corresponding BAS;

[0050] Based on whether load balancing is enabled when the BAS advertises routes, it advertises Border Gateway Protocol (BGP) routes with load balancing to the CR.

[0051] In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network;

[0052] In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

[0053] In some embodiments, the method is further used to implement a coordinated disaster recovery implementation process for an IPv4 Internet dedicated line in the downlink direction, and the method further includes:

[0054] In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm;

[0055] Based on whether the visitor BAS sends the response message to BAS1 or BAS2, the response message is sent to the client terminal through the corresponding BAS.

[0056] The present application provides a system and method for realizing disaster recovery collaboration of an IPv4 Internet dedicated line, the system comprising: a customer terminal, a customer edge device CE, an access network, an aggregation switch SW, a broadband access server BAS, a core router CR, and a visitor BAS; wherein the customer terminal is provided with a three-layer CE, and the BAS comprises BAS1 and BAS2, and the system is used to realize the disaster recovery collaboration process of an IPv4 Internet dedicated line in the upstream direction, wherein: in response to receiving an upstream message from the customer terminal, the CE performs load sharing upstream by equal-cost default, and the access network and the aggregation switch upstream the upstream message through a layer-2 VLAN; in response to receiving the upstream message, BAS1 and BAS2 publish a Border Gateway Protocol BGP route carrying a load sharing feature to the CR based on whether the load sharing feature is deployed when the BAS publishes the route as a judgment condition; in response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network; in response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table, and the visitor BAS is used to forward the service message to the visitor's network. This application provides a system and method for implementing coordinated disaster recovery for IPv4 dedicated internet lines. For client-side Layer 3 CE scenarios, this system can achieve bidirectional load balancing (IPv4) between the access and aggregation layers. For client-side Layer 2 CE scenarios, this system can achieve active / standby disaster recovery for upstream traffic and load balancing for downstream traffic. This application effectively implements disaster recovery for IPv4 dedicated internet lines and data center customers. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0058] Figure 1 A schematic diagram of a single convergence layer load sharing IPv4 / v6 method in the prior art;

[0059] Figure 2 Schematic diagram of three access layer protection modes in the prior art;

[0060] Figure 3 This is a schematic diagram of IPv4 / v6 in a dual-aggregation layer active / standby scenario in the prior art;

[0061] Figure 4 Schematic diagram of a client-side three-layer CE IPv4 Internet dedicated line disaster recovery collaborative implementation system provided in an embodiment of the present application;

[0062] Figure 5 A schematic diagram of the uplink flow of the system for implementing disaster recovery collaboration of IPv4 Internet dedicated lines on the client side of a Layer 3 CE according to an embodiment of the present application;

[0063] Figure 6 Another schematic diagram of the uplink process of the system for implementing disaster recovery collaboration of IPv4 Internet dedicated lines for client-side three-layer CE provided in an embodiment of the present application;

[0064] Figure 7 A schematic diagram of the downlink process of the client-side three-layer CE IPv4 Internet dedicated line disaster recovery collaborative implementation system provided in an embodiment of the present application;

[0065] Figure 8 Another schematic diagram of the downlink process of the system for implementing disaster recovery collaboration of IPv4 Internet dedicated lines on the client side of the three-layer CE provided in the embodiment of the present application;

[0066] Figure 9 Schematic diagram of a client-side Layer 2 CE IPv4 Internet dedicated line disaster recovery collaborative implementation system provided in an embodiment of the present application;

[0067] Figure 10 A schematic diagram of the uplink flow of the system for implementing IPv4 Internet dedicated line disaster recovery collaboration for a client-side Layer 2 CE provided in an embodiment of the present application;

[0068] Figure 11 Another schematic diagram of the uplink process of the system for implementing disaster recovery collaboration of IPv4 Internet dedicated lines for client-side Layer 2 CE provided in an embodiment of the present application;

[0069] Figure 12 A schematic diagram of the downlink process of the IPv4 Internet dedicated line disaster recovery collaborative implementation system for the client-side Layer 2 CE provided in an embodiment of the present application;

[0070] Figure 13 This is another schematic diagram of the downlink process of the IPv4 Internet dedicated line disaster recovery collaborative implementation system for the client-side Layer 2 CE provided in an embodiment of the present application.

[0071] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0072] In order to enable those skilled in the art to better understand the technical solution of the present application, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0073] It should be understood that the specific embodiments and drawings described herein are only used to explain the present application, rather than to limit the present application.

[0074] It can be understood that, in the absence of conflict, the various embodiments and features in the embodiments of the present application can be combined with each other.

[0075] It will be understood that, for the sake of ease of description, the drawings of this application only show the parts related to this application, while the parts not related to this application are not shown in the drawings.

[0076] It can be understood that each unit and module involved in the embodiments of the present application may correspond to only one physical structure, or may be composed of multiple physical structures, or multiple units and modules may be integrated into one physical structure.

[0077] It can be understood that the terms "first", "second", etc. in the embodiments of the present application are used to distinguish different objects, or to distinguish different processing of the same object, rather than to describe a specific order of objects.

[0078] It is understandable that, in the absence of conflict, the functions and steps marked in the flowcharts and block diagrams of the present application may occur in an order different from that marked in the drawings.

[0079] It is understood that the flowcharts and block diagrams of the present application illustrate the possible architectures, functions, and operations of the systems, devices, equipment, and methods according to the various embodiments of the present application. Each box in the flowchart or block diagram may represent a unit, module, program segment, or code, which contains executable instructions for implementing the specified functions. Moreover, each box or combination of boxes in the block diagram and flowchart may be implemented by a hardware-based system that implements the specified functions, or by a combination of hardware and computer instructions.

[0080] It can be understood that the units and modules involved in the embodiments of the present application can be implemented by software or hardware, for example, the units and modules can be located in a processor.

[0081] Before describing the embodiments of the present application, the English abbreviations involved in the embodiments of the present application are explained:

[0082] IPv4 (Internet Protocol Version 4): A network layer protocol for packet switching, widely used to transmit data on the Internet.

[0083] IPv6 (Internet Protocol Version 6): The next generation version of the Internet Protocol, designed to solve the problem of IPv4 address exhaustion and provide a larger address space and enhanced functions.

[0084] CE (Customer Edge): A device located between the user network and the service provider network, used to connect the enterprise network to the service provider's network.

[0085] SW (Switch): A network device used to connect network segments within a local area network and forward data based on the MAC address of the data packet.

[0086] BAS (Broadband Access Server): A network device used to manage user access and traffic on a broadband network.

[0087] SR (Service Router): A network router designed specifically to provide value-added services such as QoS and security.

[0088] VLAN (Virtual Local Area Network): A local area network that is logically divided on a physical network through a switch, which can isolate broadcast domains.

[0089] BGP (Border Gateway Protocol): A protocol used to exchange routing information between autonomous systems on the Internet.

[0090] RR (Route Reflector): A BGP route reflector used to propagate routing information in networks that do not fully conform to BGP peer connectivity.

[0091] Ethernet VPN (EVPN): A VPN technology used to provide Ethernet services on Layer 2 and Layer 3 networks.

[0092] VRRP (Virtual Router Redundancy Protocol): A selection and failover protocol for high availability of routers.

[0093] ARP (Address Resolution Protocol) table entries: used to store the correspondence between IP addresses and MAC addresses in the network.

[0094] MAC address (Media Access Control Address): A MAC address is the physical address of a device and is used to identify a network interface controller. Each device has a unique MAC address.

[0095] IP address (Internet Protocol Address): An IP address is a logical address used by a device to communicate on a network and is used to identify the device on the network.

[0096] EUI64 (Extended Unique Identifier 64-bit): used to generate a globally unique network interface identifier.

[0097] DHCP (Dynamic Host Configuration Protocol): A network protocol used to automatically assign IP addresses and network configuration parameters to devices on a network.

[0098] ND (Neighbor Discovery): Part of the IPv6 protocol, used for node discovery and automatic configuration.

[0099] PD (Prefix Delegation): A mechanism in IPv6 used to delegate network prefixes from an upper-level router to a lower-level router.

[0100] SLAAC (Stateless Address Auto Configuration): An address configuration method in IPv6 that allows nodes to automatically configure addresses without external assistance.

[0101] CR (Core Router): Located at the core of the network, it is mainly used for data packet routing and forwarding.

[0102] Furthermore, in communications networks, CE devices are typically responsible for connecting an enterprise or individual's internal network to a service provider's PE (Provider Edge) device. Depending on the network design and requirements, CE devices can be either Layer 3 or Layer 2 devices.

[0103] The following is a detailed explanation of Layer 3 CE and Layer 2 CE:

[0104] (1) Layer 3 CE (Layer 3 equipment):

[0105] (1.1) Definition: Layer 3 CE refers to client-side equipment that has Layer 3 network functions (network layer functions in the OSI model), typically used for routing data packets.

[0106] (1.2) Features:

[0107] Routing function: Layer 3 CE can run routing protocols (such as OSPF, BGP, and EIGRP) and can exchange dynamic routes with service provider equipment (PE, Provider Edge).

[0108] Independent IP management: Customers can manage their own IP address allocation and network routing.

[0109] Multiple WAN connections: Layer 3 CEs are typically connected to multiple WAN interfaces for redundancy and load balancing.

[0110] Typical equipment: router or layer 3 switch with routing function.

[0111] (1.3) Applicable scenarios:

[0112] Large enterprise networks where customers require higher autonomy and complex network configurations.

[0113] When using services such as MPLS VPN, customer devices need to participate in routing protocols.

[0114] (2) Layer 2 CE (Layer 2 equipment):

[0115] (2.1) Definition: Layer 2 CE refers to client-side equipment that only works at Layer 2 (the data link layer in the OSI model) and is primarily used for Ethernet switching and frame forwarding.

[0116] (2.2) Features:

[0117] Switching function: Layer 2 CE is only responsible for forwarding frames and does not need to run routing protocols.

[0118] Transparent transmission: The Layer 2 CE forwards traffic to the service provider's network (usually a PE device), which is responsible for routing.

[0119] Simple configuration: Layer 2 CE configuration is simple. You don’t need to worry about IP routing. You only need to set up VLAN or port mapping.

[0120] Typical equipment: Layer 2 switch or Ethernet bridge.

[0121] (2.3) Applicable scenarios:

[0122] Small and medium-sized enterprise networks or branch offices only need to implement a simple Layer 2 connection through the operator.

[0123] Point-to-point or point-to-multipoint Layer 2 VPN (such as VPLS and E-LAN).

[0124] The following table summarizes the main differences between Layer 3 CE and Layer 2 CE:

[0125]

[0126] In the existing technology, there are two main methods for coordinating disaster recovery between Internet dedicated lines and data center customers.

[0127] (1) The first method: using a single convergence layer load sharing IPv4 / v6 method.

[0128] Figure 1 This is a schematic diagram of the single convergence layer load sharing IPv4 / v6 method in the existing technology, as shown in FIG. Figure 1 As shown, the method is divided into IPv4 application scenario and IPv6 application scenario.

[0129] In IPv4 applications, dedicated internet lines and data center customer CE devices converge via two (or more) access network paths to the same aggregation switch (SW) and the same broadband access server (BAS) / service router (SR). For downstream traffic, the BAS uses two sub-interfaces to point the customer's service IPv4 address to different interconnected IPv4 addresses through static or dynamic routing, meeting the customer's internet access needs.

[0130] In addition to the above protection mode, there are three modes at the access network level: Figure 2 Schematic diagram of three access layer protection modes in the prior art, such as Figure 2 As shown, the details are as follows:

[0131] (1) The customer SW is connected to different access layer devices through two different links, and then connected to the aggregation switch through the same VLAN transparent transmission + the same service address, and then connected to the same BAS / SR.

[0132] (2) The customer CE (can be a router / switch / firewall) is connected to the same access layer device through two links, then connected to the aggregation switch, and then connected to the same BAS / SR.

[0133] (3) The customer CE (can be a router / switch / firewall) is connected to different access layer devices through two links, then connected to the aggregation switch, and then connected to the same BAS / SR.

[0134] In addition, in IPv6 application scenarios, the specific protection method is similar to IPv4. The Internet dedicated line and data center customer CE equipment are converged to the same aggregation switch SW and broadband access server BAS / service router SR through two (or more) access network paths. In the downstream traffic, BAS uses two sub-interfaces to point the customer's business IPv6 address to different interconnected IPv6 addresses through static routing or dynamic routing, realizing the customer's need to access the Internet.

[0135] In summary, although the first type of solution can partially solve customer services at the access layer, there is a single point of failure risk in the aggregation layer switches, broadband access servers BAS / service routers SR, and end-to-end protection of Internet dedicated lines and data center customer services cannot be guaranteed.

[0136] (2) The second method: using dual-aggregation layer active / standby IPv4 / v6 scenarios.

[0137] Figure 3 This is a schematic diagram of IPv4 / v6 in a dual-aggregation layer active / standby scenario in the prior art. Figure 3 As shown, the method is divided into IPv4 application scenario and IPv6 application scenario.

[0138] In IPv4 applications, dedicated internet lines and data center customer CE devices converge via two (or more) access network paths to different aggregation switches (SWs), broadband access servers (BASs), and service routers (SRs). For downstream traffic, the BAS uses two sub-interfaces to direct the customer's service IPv4 address to different interconnected IPv4 addresses through static or dynamic routing, enabling customer internet access.

[0139] Furthermore, in IPv6 application scenarios, the specific protection methods are similar to those for IPv4. This architecture employs an internet dedicated line and data center customer CE devices, each traversing two (or more) access network paths, before converging to different aggregation switches (SW) and broadband access servers (BAS) / service routers (SR). For downstream traffic, the BAS uses two sub-interfaces to direct the customer's service IPv6 address to different interconnected IPv6 addresses through static or dynamic routing, enabling customer internet access.

[0140] In summary, in the second type of solution, although disaster recovery protection can be implemented at the access layer and aggregation layer, when the BAS / SR publishes service routes, under the BGP+RR architecture, the visitor can only choose the path corresponding to one of the BAS / SRs, that is, only the active-standby protection effect can be achieved, and the service load sharing effect, IP address roaming, and seamless migration cannot be achieved.

[0141] Therefore, both the first and second methods have very obvious common defects, which are specifically reflected in the following four aspects:

[0142] (1) In a single-aggregation layer load-sharing IPv4 / 6 scenario, the aggregation layer switches (SW), broadband access servers (BAS), and service routers (SR) present single-point risks. If a failure or downtime occurs or a cutover or upgrade occurs, all services will be blocked.

[0143] (2) In the dual-aggregation layer active / standby scenario, IPv4 / v6 can only achieve active / standby, not load balancing;

[0144] (3) In addition to issues 1 and 2, IPv6 addresses need to be manually configured. Since IPv6 addresses have a large number of bits (128 bits in binary, 32 bits in hexadecimal, and abbreviations exist for various situations), in large-scale deployment of Internet dedicated lines and data centers, there are risks such as high workload, easy errors, and complex reading and writing.

[0145] (4) In addition to issues 1 and 2, there is also the lack of IP address roaming and seamless migration.

[0146] These issues are particularly prominent in the areas of dedicated internet lines and data center customers, and existing solutions cannot fully address them. The market needs to address these current challenges by providing customers with disaster recovery and collaborative network services that offer higher reliability and more secure business operations.

[0147] To address the above shortcomings, this application proposes a system and method for implementing disaster recovery collaboration on IPv4 dedicated lines. The system includes two IPv4 solutions: one with three-layer CE on the client side and one with two-layer CE on the client side. Specifically, the system includes:

[0148] (1) A system and method for bidirectional load balancing IPv4 at dual aggregation layers with three-layer CE on the client side. Upstream traffic on the client side is connected to different aggregation switches SW, different broadband access servers BAS, or service routers SR from different access layers (load balancing) via an equal-cost default routing path. Downstream traffic on the Internet side enters different aggregation switches SW via different broadband access servers BAS and service routers SR (load balancing), and then flows downstream to the client side via different access layers. This can achieve bidirectional load balancing IPv4 effects at the access layer and aggregation layer.

[0149] (2) A system and method for unidirectional load balancing IPv4 at dual aggregation layers of client-side Layer 2 CE. Upstream traffic on the client side enters the primary access layer through the default gateway in a unidirectional disaster recovery manner, and then connects to the primary aggregation switch SW, the primary broadband access server BAS, and the service router SR. Downstream traffic on the Internet side enters different aggregation switches SW through different broadband access servers BAS and service routers SR (load sharing), and then flows downstream to the client side through different access layers. This can achieve the effect of active-standby disaster recovery for upstream traffic and load balancing for downstream traffic in IPv4.

[0150] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0151] Figure 4 Schematic diagram of the client-side three-layer CE IPv4 Internet dedicated line disaster recovery collaborative implementation system provided in the embodiment of the present application, Figure 5 The schematic diagram of the uplink flow of the client-side three-layer CE IPv4 Internet dedicated line disaster recovery collaborative implementation system provided in the embodiment of the present application is as follows: Figure 4 as well as Figure 5 As shown, the present application provides an IPv4 Internet dedicated line disaster recovery collaborative implementation system, the system comprising: a customer terminal, a customer edge device CE, an access network, a convergence switch SW, a broadband access server BAS, a core router CR, and a visitor BAS;

[0152] The client terminal is provided with three layers of CE, and the BAS includes BAS1 and BAS2. The system is used to implement the coordinated disaster recovery process of the IPv4 Internet dedicated line in the uplink direction, wherein:

[0153] In response to receiving uplink messages from client terminals, the CE performs load balancing uplink traffic using equal-cost defaults. The access network and aggregation switches forward the uplink messages through a Layer 2 VLAN.

[0154] In response to receiving the uplink message, BAS1 and BAS2 publish Border Gateway Protocol (BGP) routes with load balancing to the CR, based on whether load balancing is enabled when the BAS advertises the route.

[0155] In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network;

[0156] In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

[0157] In some embodiments, in response to receiving an uplink message, BAS1 and BAS2 publish a Border Gateway Protocol (BGP) route carrying the load balancing feature to the CR based on whether the load balancing feature is deployed when the BAS publishes the route as a judgment condition, specifically including:

[0158] If load balancing is enabled, Border Gateway Protocol (BGP) routes with load balancing are advertised to the CR.

[0159] If the load balancing feature is not deployed, the BAS creates an access control list to match the IPv4 range of the customer dedicated line, prepares a route advertisement policy, and advertises Border Gateway Protocol (BGP) routes with the load balancing feature to the CR.

[0160] Specifically, Figure 6 Another schematic diagram of the uplink process of the client-side three-layer CE IPv4 Internet dedicated line disaster recovery collaborative implementation system provided in the embodiment of the present application is as follows Figure 6 As shown in Figure 1, the packet processing flow for an IPv4 customer dedicated line (Layer 3 CE) in the upstream direction includes:

[0161] Step 101: The client terminal configures the service IPv4 and gateway and sends an uplink message.

[0162] Step 102: CE receives the message and performs load balancing uplink by default using equal cost.

[0163] Step 103: The access network and aggregation switch transmit the message upstream through the Layer 2 VLAN.

[0164] Step 104, BAS1 and BAS2 receive the uplink message;

[0165] Step 105: Whether the load balancing feature is deployed when the BAS publishes the route is used as a judgment condition. If the load balancing feature is deployed, then go to step 109. If the load balancing feature is not deployed, then go to step 106.

[0166] Step 106: BAS creates an access control list matching the IPv4 range of the customer dedicated line.

[0167] Step 107: Write a routing announcement policy.

[0168] Step 108: BAS publishes BGP routes with load balancing features.

[0169] Step 109: The CR receives the corresponding BGP route.

[0170] Step 110: The CR simultaneously publishes two customer service routes to other BASs in the network.

[0171] Step 111, the guest BAS receives and places two equal-cost routes matching BAS1 and BS2 in the routing table;

[0172] Step 112: The visitor BAS forwards the service message to the visitor's network.

[0173] Step 113: The visitor receives the customer service message.

[0174] In some embodiments, the system is also used to implement a coordinated disaster recovery process for an IPv4 Internet dedicated line in the downstream direction.

[0175] Figure 7 A schematic diagram of the downlink process of the client-side three-layer CE IPv4 Internet dedicated line disaster recovery collaborative implementation system provided in the embodiment of the present application is as follows Figure 7 As shown, where:

[0176] In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm;

[0177] In response to receiving the response message, BAS1 or BAS2 sends the response message to the corresponding uplink port of CE according to the static / dynamic routing method;

[0178] In response to receiving the response message, the CE forwards the response message to the client terminal.

[0179] Specifically, Figure 8 Another schematic diagram of the downlink process of the client-side three-layer CE IPv4 Internet dedicated line disaster recovery collaborative implementation system provided in the embodiment of the present application is as follows Figure 8 As shown, specifically including:

[0180] Step 201: The visitor sends a response message to the dedicated line customer;

[0181] Step 202: The visitor BAS receives the response message.

[0182] Step 203: The visitor BAS forwards the message to BAS1 or BAS2 via the CR according to the HASH distribution algorithm and the target IP address of the client or the source address of the visitor in a load balancing manner.

[0183] Step 204: BAS1 or BAS2 sends the message to the uplink port corresponding to the customer CE according to the static / dynamic routing method;

[0184] Step 205: After receiving the message, the client CE forwards the message to the client terminal;

[0185] Step 206: The client terminal receives the downlink message.

[0186] Figure 9 Schematic diagram of the client-side Layer 2 CE IPv4 Internet dedicated line disaster recovery collaborative implementation system provided in the embodiment of the present application, Figure 10 The schematic diagram of the uplink flow of the IPv4 Internet dedicated line disaster recovery collaborative implementation system for the client-side Layer 2 CE provided in the embodiment of the present application is as follows: Figure 9 as well as Figure 10As shown, the present application provides an IPv4 Internet dedicated line disaster recovery collaborative implementation system, the system comprising: a customer terminal, a customer edge device CE, an access network, a convergence switch SW, a broadband access server BAS, a core router CR, and a visitor BAS;

[0187] The client terminal is provided with a layer 2 CE, the BAS includes BAS1 and BAS2, and the system is used to implement a coordinated disaster recovery process of an IPv4 Internet dedicated line in the uplink direction, wherein:

[0188] In response to the client terminal sending an uplink message, the downlink service sub-interfaces of BAS1 and BAS2 belong to the same Layer 2 Ethernet virtual private network EVPN domain, and BAS1 and BAS2 run the Virtual Router Redundancy Protocol VRRP heartbeat through the Layer 2 EVPN domain;

[0189] Based on whether the BAS is active, VRRP is used as a criterion to send the uplink message to the corresponding BAS;

[0190] Based on whether load balancing is enabled when the BAS advertises routes, it advertises Border Gateway Protocol (BGP) routes with load balancing to the CR.

[0191] In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network;

[0192] In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

[0193] In some embodiments, based on whether the BAS is active, VRRP is used as a judgment condition to send an uplink message to the corresponding BAS, specifically including:

[0194] If BAS1 is the active VRRP, the uplink message is sent to BAS1 via the left link;

[0195] If BAS2 is the active VRRP server, the uplink message is sent to BAS2 via the right link.

[0196] In some embodiments, based on whether the load balancing feature is deployed when the BAS advertises the route, advertising a Border Gateway Protocol (BGP) route with the load balancing feature to the CR specifically includes:

[0197] If load balancing is enabled, Border Gateway Protocol (BGP) routes with load balancing are advertised to the CR.

[0198] If the load balancing feature is not deployed, the BAS creates an access control list to match the IPv4 range of the customer dedicated line, prepares a route advertisement policy, and advertises Border Gateway Protocol (BGP) routes with the load balancing feature to the CR.

[0199] Specifically, Figure 11 Another schematic diagram of the uplink process of the IPv4 Internet dedicated line disaster recovery collaborative implementation system for the client-side Layer 2 CE provided in the embodiment of the present application is as follows Figure 11 As shown in Figure 2, the packet processing flow for an IPv4 customer dedicated line (Layer 2 CE) in the uplink direction includes:

[0200] Step 301: The customer manually configures the service IPv4 and gateway and sends an uplink message.

[0201] Step 302: The downlink service sub-interfaces of BAS1 and BAS2 belong to the same Layer 2 EVPN domain.

[0202] Step 303: BAS1 and BAS2 run VRRP heartbeat via the Layer 2 EVPN domain.

[0203] Step 304: Based on whether the BAS is using VRRP as the primary, if BAS1 is using VRRP as the primary, then proceed to step 306, where the client's uplink message is sent to BAS1 via the left link. If BAS2 is using VRRP as the primary, then proceed to step 305, where the client's uplink message is sent to BAS2 via the right link.

[0204] Step 305: The client's uplink message is sent to BAS2 via the right link.

[0205] Step 306: The client's uplink message is sent to BAS1 via the left link.

[0206] Step 307: Whether the load balancing feature is deployed when the BAS publishes the route is used as a judgment condition. If the load balancing feature is deployed, the process proceeds to step 311. If the load balancing feature is not deployed, the process proceeds to step 308.

[0207] Step 308: BAS creates an access control list to match the IPv4 range of the customer's dedicated line.

[0208] Step 309: Write a routing announcement policy.

[0209] Step 310: The BAS publishes a BGP route with load balancing features.

[0210] Step 311: The CR receives the corresponding BGP route.

[0211] Step 312: The CR simultaneously publishes two customer service routes to other BASs in the network.

[0212] Step 313, the guest BAS receives and places two equal-cost routes matching BAS1 and BS2 in the routing table;

[0213] Step 314: The visitor BAS forwards the service message to the visitor's network.

[0214] Step 315: The visitor receives the customer service message.

[0215] In some embodiments, the system is also used to implement a coordinated disaster recovery process for an IPv4 Internet dedicated line in the downstream direction.

[0216] Figure 12 A schematic diagram of the downlink process of the IPv4 Internet dedicated line disaster recovery collaborative implementation system for the client-side Layer 2 CE provided in the embodiment of the present application is shown as follows: Figure 12 As shown, where:

[0217] In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm;

[0218] Based on whether the visitor BAS sends the response message to BAS1 or BAS2, the response message is sent to the client terminal through the corresponding BAS.

[0219] In some embodiments, based on whether the visitor BAS sends the response message to BAS1 or BAS2 as a judgment condition, the response message is sent to the client terminal through the corresponding BAS, specifically including:

[0220] If the visitor BAS sends a response message to BAS1, BAS1 sends a downlink message to the client terminal according to the Address Resolution Protocol ARP table entry;

[0221] If the visitor BAS sends a response message to BAS2, BAS2 sends an ARP probe message to the client terminal; in response to receiving the terminal media access control MAC address and Internet Protocol IP address returned by the client terminal based on the ARP probe message, BAS2 establishes a corresponding ARP table entry and sends a downlink message to the client terminal according to the ARP table entry.

[0222] Specifically, Figure 13 Another schematic diagram of the downlink process of the IPv4 Internet dedicated line disaster recovery collaborative implementation system for the client-side Layer 2 CE provided in the embodiment of the present application is as follows Figure 13 As shown, specifically including:

[0223] Step 401: The visitor sends a response message to the dedicated line customer;

[0224] Step 402: The visitor BAS receives the response message;

[0225] Step 403: The visitor BAS forwards the message to BAS1 or BAS2 via the CR according to the HASH distribution algorithm and the target IP address of the client or the source address of the visitor in a load-sharing manner.

[0226] Step 404: Determine whether the visitor BAS sends the downlink message to BAS1 or BAS2. If it is sent to BAS1, proceed to step 409. If it is sent to BAS2, proceed to step 405.

[0227] Step 405: BAS2 actively sends an ARP probe message to the client terminal;

[0228] Step 406: The client terminal responds to the probe message and returns the terminal MAC and IP;

[0229] Step 407, BAS2 creates a corresponding ARP entry;

[0230] Step 408: BAS2 sends a downlink message to the client terminal according to the ARP entry.

[0231] Step 409: BAS1 sends a downlink message to the client terminal according to the ARP entry.

[0232] Step 410: The client terminal receives a downlink message.

[0233] Based on the above system, the present application provides a method for implementing disaster recovery collaboration for an IPv4 Internet dedicated line. The client terminal is provided with a three-layer CE. The method is used to implement a disaster recovery collaboration process for an IPv4 Internet dedicated line in the uplink direction. The method includes:

[0234] In response to receiving uplink messages from client terminals, the CE performs load balancing uplink traffic using equal-cost defaults. The access network and aggregation switches forward the uplink messages through a Layer 2 VLAN.

[0235] In response to receiving the uplink message, BAS1 and BAS2 publish Border Gateway Protocol (BGP) routes with load balancing to the CR, based on whether load balancing is enabled when the BAS advertises the route.

[0236] In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network;

[0237] In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

[0238] In some embodiments, the method is further used to implement a coordinated disaster recovery implementation process for an IPv4 Internet dedicated line in the downlink direction, and the method further includes:

[0239] In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm;

[0240] In response to receiving the response message, BAS1 or BAS2 sends the response message to the corresponding uplink port of CE according to the static / dynamic routing method;

[0241] In response to receiving the response message, the CE forwards the response message to the client terminal.

[0242] Based on the above system, the present application provides a method for implementing disaster recovery collaboration for an IPv4 Internet dedicated line. The client terminal is provided with a Layer 2 CE. The method is used to implement a disaster recovery collaboration process for an IPv4 Internet dedicated line in the uplink direction. The method includes:

[0243] In response to the client terminal sending an uplink message, the downlink service sub-interfaces of BAS1 and BAS2 belong to the same Layer 2 Ethernet virtual private network EVPN domain, and BAS1 and BAS2 run the Virtual Router Redundancy Protocol VRRP heartbeat through the Layer 2 EVPN domain;

[0244] Based on whether the BAS is active, VRRP is used as a criterion to send the uplink message to the corresponding BAS;

[0245] Based on whether load balancing is enabled when the BAS advertises routes, it advertises Border Gateway Protocol (BGP) routes with load balancing to the CR.

[0246] In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network;

[0247] In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

[0248] In some embodiments, the method is further used to implement a coordinated disaster recovery implementation process for an IPv4 Internet dedicated line in the downlink direction, and the method further includes:

[0249] In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm;

[0250] Based on whether the visitor BAS sends the response message to BAS1 or BAS2, the response message is sent to the client terminal through the corresponding BAS.

[0251] This application provides a system and method for implementing coordinated disaster recovery for IPv4 dedicated internet lines. For client-side Layer 3 CE scenarios, this system can achieve bidirectional load balancing (IPv4) between the access and aggregation layers. For client-side Layer 2 CE scenarios, this system can achieve active / standby disaster recovery for upstream traffic and load balancing for downstream traffic. This application effectively implements disaster recovery for IPv4 dedicated internet lines and data center customers.

[0252] It should be understood that, although the various steps in the flowcharts of the above embodiments are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they may be performed in other orders. Moreover, at least a portion of the steps in the figure may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily performed at the same time, but may be performed at different times, and their execution order is not necessarily sequential, but may be performed in turn or alternately with other steps or at least a portion of sub-steps or stages of other steps.

[0253] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present application, and such modifications and improvements are also considered to be within the scope of protection of the present application.

Claims

1. An IPv4 Internet dedicated line disaster recovery collaborative implementation system, characterized in that: The system includes: a customer terminal, a customer edge device CE, an access network, an aggregation switch SW, a broadband access server BAS, a core router CR, and a visitor BAS; The client terminal is provided with three layers of CE, and the BAS includes BAS1 and BAS2. The system is used to implement the coordinated disaster recovery process of the IPv4 Internet dedicated line in the uplink direction, wherein: In response to receiving uplink messages from client terminals, the CE performs load balancing uplink traffic using equal-cost defaults. The access network and aggregation switches forward the uplink messages through a Layer 2 VLAN. In response to receiving the uplink message, BAS1 and BAS2 publish Border Gateway Protocol (BGP) routes with load balancing to the CR, based on whether load balancing is enabled when the BAS advertises the route. In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network; In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

2. The IPv4 Internet dedicated line disaster recovery collaborative implementation system according to claim 1, characterized in that: In response to receiving the uplink message, BAS1 and BAS2 advertise BGP routes with load balancing to the CR based on whether load balancing is enabled when the BAS advertises the route. The following steps are performed: If load balancing is enabled, Border Gateway Protocol (BGP) routes with load balancing are advertised to the CR. If the load balancing feature is not deployed, the BAS creates an access control list to match the IPv4 range of the customer dedicated line, prepares a route advertisement policy, and advertises Border Gateway Protocol (BGP) routes with the load balancing feature to the CR.

3. The IPv4 Internet dedicated line disaster recovery collaborative implementation system according to claim 1, characterized in that: The system is also used to implement a coordinated disaster recovery process for IPv4 Internet dedicated lines in the downstream direction, wherein: In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm; In response to receiving the response message, BAS1 or BAS2 sends the response message to the corresponding uplink port of CE according to the static / dynamic routing method; In response to receiving the response message, the CE forwards the response message to the client terminal.

4. An IPv4 Internet dedicated line disaster recovery collaborative implementation system, characterized in that: The system includes: a customer terminal, a customer edge device CE, an access network, an aggregation switch SW, a broadband access server BAS, a core router CR, and a visitor BAS; The client terminal is provided with a layer 2 CE, the BAS includes BAS1 and BAS2, and the system is used to implement a coordinated disaster recovery process of an IPv4 Internet dedicated line in the uplink direction, wherein: In response to the client terminal sending an uplink message, the downlink service sub-interfaces of BAS1 and BAS2 belong to the same Layer 2 Ethernet virtual private network EVPN domain, and BAS1 and BAS2 run the Virtual Router Redundancy Protocol VRRP heartbeat through the Layer 2 EVPN domain; Based on whether the BAS is active, VRRP is used as a criterion to send the uplink message to the corresponding BAS; Based on whether load balancing is enabled when the BAS advertises routes, it advertises Border Gateway Protocol (BGP) routes with load balancing to the CR. In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network; In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

5. The IPv4 Internet dedicated line disaster recovery collaborative implementation system according to claim 4, characterized in that: Based on whether the BAS is active, VRRP is used as a criterion to send the uplink message to the corresponding BAS. Specifically, the following steps are performed: If BAS1 is the active VRRP, the uplink message is sent to BAS1 via the left link; If BAS2 is the active VRRP server, the uplink message is sent to BAS2 via the right link.

6. The IPv4 Internet dedicated line disaster recovery collaborative implementation system according to claim 4, characterized in that: Based on whether load balancing is enabled when the BAS advertises routes, it advertises BGP routes with load balancing to the CR. Specifically, the BAS advertises: If load balancing is enabled, Border Gateway Protocol (BGP) routes with load balancing are advertised to the CR. If the load balancing feature is not deployed, the BAS creates an access control list to match the IPv4 range of the customer dedicated line, prepares a route advertisement policy, and advertises Border Gateway Protocol (BGP) routes with the load balancing feature to the CR.

7. The IPv4 Internet dedicated line disaster recovery collaborative implementation system according to claim 4, characterized in that: The system is also used to implement a coordinated disaster recovery process for IPv4 Internet dedicated lines in the downstream direction, wherein: In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm; Based on whether the visitor BAS sends the response message to BAS1 or BAS2, the response message is sent to the client terminal through the corresponding BAS.

8. The IPv4 Internet dedicated line disaster recovery collaborative implementation system according to claim 7, characterized in that: Based on whether the visitor BAS sends the response message to BAS1 or BAS2, the response message is sent to the client terminal through the corresponding BAS, specifically including: If the visitor BAS sends a response message to BAS1, BAS1 sends a downlink message to the client terminal according to the Address Resolution Protocol ARP table entry; If the visitor BAS sends a response message to BAS2, BAS2 sends an ARP probe message to the client terminal; in response to receiving the terminal media access control MAC address and Internet Protocol IP address returned by the client terminal based on the ARP probe message, BAS2 establishes a corresponding ARP table entry and sends a downlink message to the client terminal according to the ARP table entry.

9. A method for realizing disaster recovery collaboration of an IPv4 Internet dedicated line, characterized in that: The client terminal is provided with three layers of CE. The method is used to implement a coordinated disaster recovery process of an IPv4 Internet dedicated line in the uplink direction. The method includes: In response to receiving uplink messages from client terminals, the CE performs load balancing uplink traffic using equal-cost defaults. The access network and aggregation switches forward the uplink messages through a Layer 2 VLAN. In response to receiving the uplink message, BAS1 and BAS2 publish Border Gateway Protocol (BGP) routes with load balancing to the CR, based on whether load balancing is enabled when the BAS advertises the route. In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network; In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

10. The method for realizing IPv4 Internet dedicated line disaster recovery collaboration according to claim 9, characterized in that: The method is also used to implement a coordinated disaster recovery process for an IPv4 Internet dedicated line in the downlink direction, and the method further comprises: In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm; In response to receiving the response message, BAS1 or BAS2 sends the response message to the corresponding uplink port of CE according to the static / dynamic routing method; In response to receiving the response message, the CE forwards the response message to the client terminal.

11. A method for realizing disaster recovery collaboration of an IPv4 Internet dedicated line, characterized in that: The client terminal is provided with a Layer 2 CE. The method is used to implement a coordinated disaster recovery process for an IPv4 Internet dedicated line in the uplink direction. The method includes: In response to the client terminal sending an uplink message, the downlink service sub-interfaces of BAS1 and BAS2 belong to the same Layer 2 Ethernet virtual private network EVPN domain, and BAS1 and BAS2 run the Virtual Router Redundancy Protocol VRRP heartbeat through the Layer 2 EVPN domain; Based on whether the BAS is active, VRRP is used as a criterion to send the uplink message to the corresponding BAS; Based on whether load balancing is enabled when the BAS advertises routes, it advertises Border Gateway Protocol (BGP) routes with load balancing to the CR. In response to receiving the BGP route, the CR publishes the customer service route to other BASs in the network; In response to receiving the customer service route, the visitor BAS places two equal-cost routes matching BAS1 and BS2 in the routing table. The visitor BAS is used to forward the service message to the visitor's network.

12. The method for realizing IPv4 Internet dedicated line disaster recovery collaboration according to claim 11, characterized in that: The method is also used to implement a coordinated disaster recovery process for an IPv4 Internet dedicated line in the downlink direction, and the method further comprises: In response to receiving the visitor's response message, the visitor BAS forwards the response message to BAS1 or BAS2 via the CR according to the load balancing method based on the client's target IP address or the visitor's source address according to the HASH distribution algorithm; Based on whether the visitor BAS sends the response message to BAS1 or BAS2, the response message is sent to the client terminal through the corresponding BAS.

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