OpenFlow Switch Request Suppression for Controller Load Reduction
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Solution Overview
Problem
The OpenFlow switch's frequent requests for flow entry setting to the OpenFlow controller can overwhelm the secure channel and increase the load on the controller, leading to performance deterioration, especially when handling large numbers of packets or multiple switches.
Innovation Solution
A communication node with an entry memory and a request suppressing unit that sets a control information entry for packets with common characteristics, suppressing subsequent flow entry setting requests for a preset time, thereby reducing the load on the secure channel and controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the OpenFlow switch requests flow entry setting for each packet without matching entry in flow table, then the control information can be set accurately for each packet, but the secure channel bandwidth is overwhelmed and controller load increases
Solution Approach 1:
The patent applies preliminary action by having the OpenFlow switch proactively send flow entry setting requests for multiple packets in advance, before they are fully processed. This allows the controller to prepare control information ahead of time, reducing the need for repeated individual requests and alleviating channel bandwidth pressure while maintaining accurate control information delivery.
Solution Approach 2:
The patent merges multiple flow entry setting requests into a single batched request mechanism. Instead of sending individual requests for each packet, the switch consolidates requests for multiple packets with common characteristics, reducing the total number of communications between switch and controller, thereby preserving channel throughput while maintaining control accuracy.
2Reliability
If the OpenFlow switch sends frequent flow entry setting requests to the OpenFlow controller, then the control information can be updated in real-time, but the response performance deteriorates due to increased controller load
Solution Approach 1:
The patent implements periodic action by establishing a time-based mechanism where flow entry setting requests are sent at optimized intervals rather than continuously for every packet. This periodic approach allows the controller to process requests more efficiently, maintaining relatively fresh control information while reducing the frequency of requests to improve response performance and reduce controller load.
Solution Approach 2:
By sending flow entry setting requests in advance for multiple packets, the controller can prepare control information before it is critically needed, reducing the effective response time for packet processing while maintaining control information freshness through proactive updates rather than reactive repeated requests.
3Measurement precision
If the OpenFlow switch makes flow entry setting requests for every packet with common characteristics, then the control accuracy is maintained, but the number of requests to the controller increases excessively
Solution Approach 1:
The patent merges flow entry setting requests for multiple packets that share common characteristics into a single consolidated request. This merging approach maintains the precision of packet matching by preserving the specific match conditions and flow characteristics, while dramatically reducing the total quantity of requests sent to the controller, thereby resolving the contradiction between accuracy and request volume.
Data Source
AI summary
A communication node includes an entry memory capable of retaining a control information entry stipulating a processing to be applied to a packet received, a packet processor referencing the entry memory to process the packet received, and a request suppressing unit. Triggered by reception of a packet, the request suppressing unit requests a preset control apparatus to set a control information entry, and subsequently suppresses control information entry setting requests for a preset time for packets having a characteristic in common with the packet for which the control information entry setting request was made to the preset control apparatus.