Flow Entry Version Control for Virtual Machine Migration
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Solution Overview
Problem
The process of migrating virtual machines in cloud computing environments involves the deletion of flow tables, which is time-consuming and can result in message forwarding errors due to incomplete deletion, leading to inefficiencies and inaccuracies in data transmission.
Innovation Solution
A method and apparatus for controlling flow entries by managing version numbers of virtual machines, allowing for efficient deletion and re-establishment of flow entries during migration, ensuring accurate data forwarding by comparing version numbers and utilizing a centrex to re-determine forwarding paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If searching and polling are performed one by one according to flow table information to delete flow entries during virtual machine migration, then all flow tables can be traversed, but the process requires a lot of time and message forwarding errors may occur
Solution Approach 1:
The patent implements a feedback mechanism where the control plane receives migration notifications from the data plane, compares version numbers to detect virtual machine migrations, and triggers flow entry deletions. This feedback loop ensures that flow entries are deleted promptly when migrations occur, preventing message forwarding errors while avoiding the need for continuous polling of all flow tables.
Solution Approach 2:
The data plane autonomously generates migration notifications when detecting virtual machine migrations, eliminating the need for the control plane to actively poll flow tables. This self-service approach allows the system to respond to migrations event-driven, reducing the time loss associated with periodic polling while maintaining reliable message forwarding.
2Productivity
If flow tables are aged and deleted before virtual machine migration, then migration can proceed, but the process requires traversing all flow tables which is time-consuming
Solution Approach 1:
The patent extracts the flow entry deletion trigger from a periodic polling mechanism to an event-driven approach. By taking out the deletion operation and coupling it directly to migration detection events, the system eliminates the need to traverse all flow tables continuously, thereby improving virtual machine migration speed without sacrificing flow table management completeness.
Solution Approach 2:
The control plane pre-establishes version number tracking and migration detection mechanisms before migration occurs. When a migration notification arrives, the system already has the necessary information (version numbers, flow entry mappings) ready, allowing immediate identification and deletion of relevant flow entries without time-consuming traversal during the migration process.
3Measurement precision
If version number comparison is implemented to detect virtual machine migration, then flow entry deletion accuracy is improved, but the system complexity increases
Solution Approach 1:
The patent uses version number parameters as a simple yet effective indicator of virtual machine migration. By monitoring changes in this single parameter (version number) rather than analyzing complex flow table contents, the system achieves high migration detection accuracy while minimizing the increase in system complexity. The version number serves as a lightweight state indicator that simplifies the overall control logic.
Data Source
AI summary
This specification provides a method and an apparatus for controlling a flow entry. The method includes: receiving a data message sent by a user, and determining a target flow entry matched with the data message, where the target flow entry is one of at least one flow entry corresponding to a target virtual machine in a local position; in a case that a first version number of the target virtual machine included in the target flow entry is inconsistent with a second version number of the target virtual machine recorded in the local position, deleting a flow entry including the first version number in the local position; and sending the data message to a centrex, so that the centrex forwards the data message to a target host machine, where the second version number is generated in a case that the target virtual machine is migrated to the target host machine.