SDN Reporting Switch Selection for Flow Table Misses
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Solution Overview
Problem
In software-defined networks, flow table overflows and premature removal of flow entries due to hard timeouts can lead to flow table misses, burdening controllers and causing packet drops, latency, and inefficient resource utilization, especially in high-load scenarios where switches may not have the resources to process flow miss packets efficiently.
Innovation Solution
Selecting an optimal network device for reporting flow table misses based on pre-defined factors such as processing capability, distance from the controller, and network infrastructure limitations, allowing the selected device to act as a 'reporting switch' and manage subsequent flow table misses, thereby optimizing the reporting process and reducing the load on the controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If flow table entries are removed upon hard timeout expiry, then flow table space is freed for new flows, but flow table misses occur causing controller burden and packet drops
Solution Approach 1:
The system performs preliminary action by selecting an optimal network device in advance to report flow table misses before they occur. When a flow entry expires, the pre-selected device is notified and can proactively report the miss condition to the controller, allowing the controller to refresh flow entries before actual packet drops occur, thus maintaining forwarding reliability while managing flow table space.
2Loss of information
If all network devices report flow table misses to the controller, then the controller can make informed forwarding decisions, but the controller becomes overloaded especially under high load scenarios
Solution Approach 1:
The system applies local quality by selecting a specific optimal network device based on its characteristics (such as proximity to controller, processing capability, or flow table miss frequency) to report flow table misses. Instead of all devices reporting equally, only the optimally selected device reports misses, thereby maintaining complete flow miss information while reducing controller overload by concentrating reporting duties on a single suitable device.
3Reliability
If flow entries are kept in the flow table beyond timeout, then flow table misses are reduced, but flow table overflow occurs reducing space for new flows
Solution Approach 1:
The system implements feedback by establishing a reporting mechanism where the optimal network device monitors flow entry expiration and reports flow table miss conditions to the controller. The controller receives this feedback and can dynamically refresh flow entries based on actual network conditions rather than relying solely on fixed timeout values. This allows flow entries to be maintained just long enough to prevent misses while freeing table space when no longer needed, balancing reliability and space capacity.
Data Source
AI summary
Examples disclosed herein relate to selecting an optimal network device for reporting flow table misses upon expiry of a flow in a software defined network, comprising. An SDN enabled device is selected, from a plurality of software defined network (SDN) enabled devices, for reporting a flow table miss upon expiry of a flow to an SDN controller, based on a pre-defined factor.