SDN Controller Group Message for Flow Table Consistency
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Solution Overview
Problem
Current software-defined networking (SDN) technologies lack methods to guarantee consistency in transactions between controllers and switches or between clients and agents, leading to potential errors and inconsistencies in flow table modifications.
Innovation Solution
A method is introduced where a controller generates a group message for modifying flow entries across multiple flow tables, which includes multiple command messages with a common structure, and transmits this message to switches. The switches verify the message and send an acknowledgement (ACK) back, allowing the controller to either execute or cancel the message based on the presence of errors, ensuring consistency and synchronization across relevant flow tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flow entries in multiple flow tables are modified using separate command messages, then each modification can be processed independently, but consistency between related flow tables cannot be guaranteed
Solution Approach 1:
The patent segments the modification process into two distinct phases: a preparation phase where multiple command messages are collected and validated, and an execution phase where they are applied atomically. This segmentation allows independent validation of each command while ensuring collective consistency through the transaction mechanism.
Solution Approach 2:
The patent introduces a transaction message as an intermediary structure that mediates between multiple command messages and the flow table modifications. This transaction message coordinates the modifications across multiple flow tables, ensuring that either all changes are applied consistently or none are applied, thus maintaining reliability.
2Reliability
If a group message includes multiple command messages for simultaneous modification, then consistency is improved, but the message structure and processing complexity increases
Solution Approach 1:
The patent performs preliminary actions by collecting and validating all command messages within the group message before execution. The switch verifies the validity of each command message and checks for conflicts during the preparation phase, ensuring that atomicity is maintained without requiring complex transaction management during execution.
Solution Approach 2:
The patent merges multiple command messages into a single group message structure that is processed atomically. By combining multiple modification commands into one transactional unit, the system ensures that all related flow table modifications are applied together, maintaining consistency while simplifying the execution model.
3Measurement precision
If the switch verifies each command message in the group message, then error detection is improved, but the verification time and processing overhead increases
Solution Approach 1:
The patent applies partial verification by checking command messages for obvious errors and conflicts during the preparation phase, without performing exhaustive validation of every detail. This approach detects critical errors that would affect consistency while avoiding excessive verification overhead, achieving a balance between accuracy and efficiency.
Data Source
AI summary
Disclosed are methods for managing transactions in a software defined network (SDN). A method performed in a controller may comprise generating a group message for modifying flow entries of a plurality of flow tables related to each other in a switch; and transmitting the group message to the switch. Thus, a plurality of flow tables having relevance to each other can be simultaneously modified so that modifications on a plurality of switches can be synchronized, and consistency of them can be guaranteed.