Network Forwarding Element Data Plane Packet Snapshotting
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Solution Overview
Problem
Debugging of data plane operations in network forwarding elements, such as switches and routers, is challenging due to the hardware-based processing of data messages without processor involvement, limiting traditional software debugging methods.
Innovation Solution
Incorporating snapshot debug hardware circuits that capture and process data messages within the data plane, allowing for specific data snapshotting, storage, and notification to the CPU, enabling effective debugging of data plane operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional software debugging methods are used for data plane operations, then debugging can be performed by placing break points in software, but this method is ineffective for hardware-based data plane processing without processor involvement
Solution Approach 1:
The patent introduces snapshot capture circuits as an intermediary mechanism between the hardware data plane and the control plane processor. These circuits capture snapshots of data messages at various processing stages and transfer them to the control plane, enabling traditional software debugging methods to work effectively with hardware-based data plane operations without requiring processor involvement in the actual forwarding path.
Solution Approach 2:
The patent creates copies of data messages through snapshot capture circuits that duplicate data message information at different processing stages. These copies are then available for analysis by the control plane processor without interfering with the original data message forwarding, allowing debugging while maintaining normal data plane operation.
2Speed
If hardware-based processing is used for data messages, then forwarding speed is improved, but traditional software debugging methods become inapplicable
Solution Approach 1:
The patent creates copies of data messages through snapshot capture circuits that duplicate data message information at different processing stages. These copies are then available for analysis by the control plane processor without interfering with the original data message forwarding, allowing debugging while maintaining normal data plane operation.
Solution Approach 2:
The patent segments the debugging function from the data plane forwarding path by placing snapshot capture circuits within the data plane hardware while allowing control plane software to analyze the captured data. This segmentation enables independent optimization of forwarding speed in the data plane and debugging capability in the control plane.
3Ease of operation
If snapshot capture circuits are added to the data plane, then debugging capability is improved, but device complexity increases
Solution Approach 1:
The snapshot capture circuits are designed to work with multiple message processing pipelines and can capture data at various stages of processing. This multi-functionality allows a single hardware component to serve debugging purposes across different data message types and processing paths, reducing overall system complexity despite the added capability.
Data Source
AI summary
A forwarding element includes data plane forwarding circuitry for forwarding data messages received by the forwarding element to other network elements in a network. The data-plane forwarding circuitry includes several snapshot-match circuitry units. Each snapshot-match circuitry unit compares a set of header fields of incoming data messages with a corresponding matching data. The data-plane forwarding circuitry also includes several snapshot-capture circuitry units. Each snapshot-capture circuitry units stores a set of header fields of data messages that matches a corresponding matching data.