Active-Standby Router Disaster Tolerance via Layer 3 Route Advertisement
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Solution Overview
Problem
Current disaster tolerance solutions, such as VRRP, are not suitable for remote deployments as they require devices to be in the same layer 2 switching network and involve high capacity requirements and potential service interruptions due to different IP addresses.
Innovation Solution
A method where a device with an active-standby function determines its state and advertises reachable route information to a connected routing device using a layer 3 protocol, allowing the active device to remain reachable without needing ARP responses, enabling remote disaster tolerance without the limitations of VRRP and maintaining the same IP address for active and standby devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VRRP solution is used with active and standby routers in the same layer 2 switching network, then disaster tolerance is achieved, but the solution is not suitable for remote deployments where layer 2 switching network cannot be provided
Solution Approach 1:
The patent introduces a virtual IP address as an intermediary between the active router and standby router. This virtual IP address allows the standby router to respond to ARP requests independently while maintaining the appearance of a single active router to external hosts, enabling remote disaster tolerance without requiring layer 2 connectivity between active and standby routers
Solution Approach 2:
The patent segments the routing function into multiple independent routers located in different networks, with each router having its own physical IP address but sharing a common virtual IP address. This segmentation allows each router to operate independently in its own network environment while maintaining disaster tolerance through the virtual IP mechanism
2Adaptability or versatility
If different IP addresses are configured for active and standby devices, then remote disaster tolerance is achieved, but device capacity requirements increase and service interruption occurs during IP address switching
Solution Approach 1:
The patent creates a virtual copy of the router's identity through a virtual IP address that can be assigned to either the active or standby router. This virtual copy maintains consistent network identity across failover events, eliminating service interruption while reducing device capacity requirements compared to managing multiple distinct IP addresses
3Adaptability or versatility
If ARP requests are responded to by multiple routers, then remote access is enabled, but determining the active router becomes complex
Solution Approach 1:
The patent pre-configures both active and standby routers with the same virtual IP address and ARP response capability before failover occurs. This preliminary configuration eliminates the complexity of real-time state management during failover, as both routers are prepared to respond to ARP requests independently without requiring complex coordination protocols
Data Source
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AI summary
Embodiments of the present invention provide a method, a device, and a system for realizing disaster tolerance backup. The method includes the following steps: a device with an active-standby function determines a current state of the device with the active-standby function, where the current state may be an active state or a standby state; after it is determined that the current state is the active state, the device with the active-standby function advertises reachable route information to a connected routing device, where the device with the active-standby function and a device of which a current state is the standby state have a same IP address, the reachable route information includes route information relevant to the IP address, so that the IP address is reachable through a route, and the device with the active-standby function and the device of which the current state is the standby state are backup devices for each other. The present invention can realize remote disaster tolerance backup and avoid service interruption.