Backup Router Probe Mechanism for Fast OSPF Failure Detection
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Solution Overview
Problem
Current OSPF networks require at least four seconds to detect a failed router and reroute traffic, which limits scalability and is inefficient in handling rapid router failures.
Innovation Solution
Implementing a Cooperative Wide Area Network Routing module or Virtual Redundancy Routing Protocol to instantly detect router failures and switch traffic to a backup router, allowing for virtually instantaneous failure detection and rerouting within 300 milliseconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard OSPF hello packet mechanisms are used for router failure detection, then network stability is maintained through periodic status checks, but router failure detection time is delayed to at least four seconds
Solution Approach 1:
The patent implements preliminary action by having the backup router proactively send a probe packet to the primary router before failure occurs. When the primary router fails to respond to this pre-established probe, the backup router immediately detects the failure and triggers rerouting, eliminating the need to wait for the next periodic hello packet cycle and achieving detection within 300 milliseconds.
Solution Approach 2:
The patent implements feedback by establishing a bidirectional communication mechanism where the backup router sends probe packets to the primary router and waits for confirmation. The absence of a response provides negative feedback indicating failure, while a positive response confirms operational status. This feedback loop enables rapid failure detection without disrupting network stability.
2Measurement precision
If backup routers continuously monitor primary router status using standard OSPF protocols, then failure detection capability is improved, but network traffic overhead and router load increase
Solution Approach 1:
The patent implements periodic action by having the backup router send probe packets at intervals rather than continuously monitoring. The probe packets are sent periodically with sufficient spacing to minimize overhead while ensuring timely detection. This periodic probing approach achieves rapid failure detection without creating excessive network traffic or router processing load.
Solution Approach 2:
The patent implements self-service by having the backup router autonomously perform monitoring and detection functions without requiring additional network infrastructure or centralized control. The backup router independently sends probe packets, processes responses, and triggers rerouting decisions, reducing overall network overhead while maintaining high detection capability.
3Productivity
If rapid rerouting to backup routers is implemented, then network availability is improved during failures, but routing protocol complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-establishing backup router relationships and probe mechanisms before failures occur. The backup router is pre-configured with the primary router's identity and monitoring parameters, so when failure occurs, the rerouting process can begin immediately without complex real-time decision-making, maintaining high availability while limiting complexity growth.
Solution Approach 2:
The patent implements parameter changes by modifying the OSPF protocol to include probe packet functionality and rapid failure detection parameters. Rather than creating an entirely new protocol, the invention changes specific parameters and adds targeted features to existing OSPF mechanisms, achieving rapid rerouting while minimizing the increase in overall protocol complexity.
Data Source
AI summary
A fast OSPF inactive router detection technique is provided that detects the failure of a router and switches routing to an alternate router. The alternate router provides a message to the other routers in the Wide Area Network (LAN) that informs of the router failure.