Transactional MHFE Updates for Consistent Data Plane Forwarding
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Solution Overview
Problem
Existing network control systems lack transactional controls for hardware forwarding elements (MHFEs), leading to incomplete and inconsistent data plane operations due to partial control plane updates, causing network disruptions.
Innovation Solution
Implement transactional communication methods ensuring that MHFEs receive the entirety of a control plane update before modifying their data plane operations, using techniques like locks or state_consistent columns to manage logical forwarding elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the MHFE starts modifying data plane operations immediately upon receiving partial control plane configuration data, then the response speed is improved, but the consistency and reliability of the data plane operations deteriorate
Solution Approach 1:
The patent applies preliminary action by having the MHFE receive and store the entire control plane configuration data set before modifying any data plane operations. The MHFE waits to receive all configuration data tuples including the LAN binding tuple, then applies the complete configuration atomically. This ensures that data plane modifications are based on complete and consistent control plane views, preventing inconsistency while maintaining reliable operation.
2Reliability
If the MHFE waits to receive the entire control plane update before modifying data plane operations, then the consistency is improved, but the response speed deteriorates
Solution Approach 1:
The patent implements feedback through the transactional boundary control mechanism where the MHFE monitors the receipt of configuration data tuples and provides feedback to the controller about the completion status. The MHFE waits for confirmation that all configuration data has been received, including the LAN binding tuple, before proceeding with data plane modifications. This feedback loop ensures atomicity and consistency while enabling efficient batch processing of complete configuration sets.
3Reliability
If transactional controls are implemented to ensure complete configuration updates, then the reliability is improved, but the system complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the configuration update process into distinct phases: a transactional boundary phase where complete configuration data is exchanged, and an execution phase where data plane operations are modified. The configuration data itself is segmented into multiple tuples with the LAN binding tuple serving as a transactional boundary marker. This segmentation enables reliable atomic updates without requiring complex distributed transaction protocols, simplifying the overall system while ensuring completeness.
Data Source
AI summary
Some embodiments provide novel methods for controllers to communicate with managed hardware forwarding elements (MHFEs) in a transactional manner. The transactional communication methods of some embodiments ensure that an MHFE receives the entirety of a control plane update that a controller supplies to it, before the MHFE starts to modify its data plane forwarding data and operations. The transactional communication methods of some embodiments provide one or more transactional boundary controls to the controllers to define complete control plane data set updates. In some embodiments, the transactional controls ensure that an MHFE receives all of a control plane update before it starts to modify its data plane forwarding data. Controllers use one transactional control in some embodiments when they define logical forwarding elements (e.g., logical switches or routers) on the MHFEs.