Data-Plane Packet Redirection via Port Mirroring During Link Failures
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Solution Overview
Problem
Network links going offline due to hardware failure or user actions result in significant packet drops and performance degradation, as upstream devices take time to detect and react to the event, leading to severe performance impacts.
Innovation Solution
The method involves detecting a link offline condition in the data plane and redirecting data packets to a redundant path, using a mirroring feature to create copies of packets with an encapsulation header, and maintaining this redirection until upstream routing tables are updated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If software coordination is used to propagate link offline events and update routing tables, then routing tables are updated to use different paths, but significant packet drops occur during the 10s to 100s of milliseconds propagation time
Solution Approach 1:
The patent pre-computes and stores alternative routing paths in forwarding tables before link failures occur. When a link goes offline, the data plane can immediately switch to pre-computed alternative paths without waiting for control plane software to propagate the failure event and recalculate routes, thereby eliminating packet drops during the propagation delay period
Solution Approach 2:
The patent introduces a data plane forwarding mechanism that acts as an intermediary between the control plane and network traffic. This data plane component maintains independent forwarding tables with alternative paths and can autonomously redirect traffic around failed links without requiring control plane intervention, thus bypassing the slow software coordination bottleneck
2Productivity
If upstream devices continue forwarding packets to downed links during software coordination, then routing tables are eventually updated, but packets forwarded during this time are dropped causing severe performance degradation
Solution Approach 1:
The patent pre-computes alternative routing paths and stores them in data plane forwarding tables before any link failure occurs. When a link goes down, the data plane immediately uses these pre-computed alternative paths to forward packets, ensuring continuous packet delivery without drops while the control plane software eventually updates its routing tables
Solution Approach 2:
The patent implements dynamic forwarding tables in the data plane that can be updated independently and faster than control plane routing tables. These dynamic forwarding tables allow the network to adapt to link failures in real-time by switching to alternative paths, maintaining high packet delivery success rates even during ongoing failures
Data Source
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AI summary
A method for redirecting data packet on link offline in a network is provided. The method includes detecting an offline link between a first port and a destination port. The method also includes moving the first port to a recovery state by turning on a mirroring feature to make copies of all subsequent frames of data packets to the first port. The method further includes activating a redundant port profile associated with the mirroring feature prepopulated with information including at least a second port linked to the destination port. Furthermore, the method includes forwarding, based on the redundant port profile, the copies of all data packets to the second port linked to the destination port.