Logical Router Failure Handling via Pre-Computed Backup Paths
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Solution Overview
Problem
Conventional failure handling in logical routers is inefficient due to high overhead and latency caused by gratuitous ARP messages, especially in large-scale networks, which is unsuitable for applications requiring rapid network convergence like real-time video streaming and VOIP.
Innovation Solution
The solution involves the first routing component learning path information associated with multiple paths before a failure, allowing it to select a new active routing component without broadcasting GARP messages, thereby reducing overhead and latency in rerouting packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gratuitous ARP messages are broadcast for failure handling, then routing information can be updated, but network overhead and latency increase significantly
Solution Approach 1:
The system pre-establishes multiple routing paths and stores path information (including next-hop addresses and interface configurations) before failure occurs. When a failure is detected, the first routing component can immediately switch to a pre-computed backup path without waiting for ARP message exchanges, thus reducing convergence time while maintaining routing accuracy
2Reliability
If GARP messages are broadcast for path rerouting, then packet forwarding can be restored, but network overhead increases
Solution Approach 1:
The patent extracts and removes the GARP message broadcasting mechanism from the failure handling process. Instead of relying on control plane ARP messages, the system uses pre-configured backup paths stored in the routing components, allowing direct data plane switching without generating additional control traffic, thus eliminating network overhead associated with GARP messages
3Reliability
If conventional failure handling is used, then routing can be restored, but convergence speed is too slow for real-time applications
Solution Approach 1:
Multiple routing paths are pre-calculated and path information is stored in advance including next-hop addresses, interface identifiers, and routing metrics. Upon failure detection, the first routing component immediately selects a pre-computed backup path and switches traffic forwarding, achieving sub-50ms convergence suitable for real-time video streaming and VOIP applications without waiting for traditional ARP-based routing updates
Data Source
AI summary
Example methods are provided for a first routing component to handle failure at a logical router in a first network. One method may comprise learning first path information associated with a first path provided by an active second routing component, and second path information associated with a second path provided by a standby second routing component. The method may also comprise in response to detecting a first egress packet destined for a second network, sending the first egress packet to the active second routing component based on the first path information. The method may further comprise in response to detecting a failure at the active second routing component and detecting a second egress packet destined for the second network, sending the second egress packet to a new active second routing component based on the second path information.