SDN Controller VM Migration Flow Table Management
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Solution Overview
Problem
In Software Defined Networks (SDNs), the storage of flow tables for virtual machine migration consumes a large portion of controller resources, as each controller needs to maintain copies of flow tables transmitted to virtual switching devices, leading to resource wastage and inefficiency.
Innovation Solution
The controller generates and records neighbor relationship tables instead of storing flow tables, using these tables to generate and update flow tables on destination hosts during virtual machine migration, eliminating the need for storing duplicate flow table copies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the controller stores flow tables for each virtual switching device to enable virtual machine migration, then migration capability is improved, but controller resource consumption increases
Solution Approach 1:
The patent extracts the flow table storage function from the controller and relocates it to the virtual switching devices. Each virtual switching device maintains its own flow tables locally, eliminating the need for the controller to store duplicate copies. This extraction resolves the contradiction by enabling migration capability while reducing controller resource consumption.
Solution Approach 2:
The patent introduces a flow table management mechanism where virtual switching devices act as intermediaries between the controller and the flow table data. The controller generates flow tables and distributes them to virtual switching devices, which then manage and update them locally. This intermediary structure enables migration while preventing resource wastage at the controller.
2Reliability
If the controller maintains copies of flow tables for all virtual switching devices, then complete network control is improved, but operational complexity increases
Solution Approach 1:
The patent segments the flow table management responsibility from the controller and assigns it to individual virtual switching devices. Each virtual switching device manages its own flow tables independently, while the controller maintains overall network control through coordination. This segmentation reduces controller operational complexity while preserving complete network control capability.
Solution Approach 2:
The controller performs preliminary action by generating and distributing flow tables to virtual switching devices before migration occurs. The virtual switching devices then maintain these tables locally and perform updates as needed. This preliminary distribution eliminates the need for the controller to continuously maintain and manage all flow table copies, reducing operational complexity.
Data Source
AI summary
Examples of the present disclosure provide a method of migrating a virtual machine. In response to receiving information of a newly added port, a first controller within a software defined network may search for a matching destination Internet protocol address within a first neighbor relationship table when an IP address contained in the information of the newly added port is taken as a source IP address. The first controller may send flow tables relating to the matching destination IP address to a destination virtual switching device of a migrated virtual machine, and update flow tables stored in virtual switching devices managed by the first controller. The first controller may send a migration success message including the information of the newly added port to a second controller, to enable the second controller to update flow tables stored in virtual switching devices managed by the second controller.