Distributed OpenFlow Controller Path Calculation
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Solution Overview
Problem
In networks with multiple OpenFlow switches, path calculations and processing requirements for flow table entries become excessively time-consuming, leading to performance degradation.
Innovation Solution
A communication system with multiple forwarding nodes and control devices, where each node performs packet processing based on pre-set or received rules, and control devices manage correspondence between nodes and devices, distributing path information and processing rules to ensure efficient packet forwarding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single OpenFlow controller manages all flow tables in multiple OpenFlow switches, then centralized path control and flow management are achieved, but the time required for path calculations and response to forwarding requests increases significantly
Solution Approach 1:
The patent divides the single centralized OpenFlow controller into multiple distributed controllers. Each controller manages a subset of OpenFlow switches and flow tables, segmenting the control function. This segmentation allows parallel path calculations for different flows, significantly reducing the overall time required while maintaining centralized control through coordinated management among controllers.
2Productivity
If multiple OpenFlow switches are deployed to increase network capacity, then network throughput and redundancy are improved, but the amount of processing required for flow table entry allocation increases
Solution Approach 1:
The patent segments the flow table management responsibility across multiple controllers, with each controller handling a specific subset of switches and flows. This division reduces the processing load on individual controllers and enables parallel processing of flow table entries across the distributed controller system, thereby managing complexity while supporting increased network capacity.
Solution Approach 2:
The patent introduces a controller association mechanism that acts as an intermediary layer between OpenFlow switches and controllers. Each switch is associated with a specific controller that handles its flow table management, reducing the complexity of coordinating multiple controllers with multiple switches. This intermediary association simplifies the mapping and management relationships in large-scale deployments.
3Measurement precision
If path calculations are performed centrally for all switches, then optimal path selection is achieved, but the response time from receiving requests to providing responses becomes excessively long
Solution Approach 1:
The patent segments path calculation responsibilities across multiple controllers, allowing simultaneous path calculations for different network segments. Each controller performs optimization calculations for its associated switches independently and in parallel, achieving overall optimal paths while dramatically reducing the time required compared to sequential centralized calculation.
Data Source
AI summary
A communication system comprises control devices, and forwarding nodes each includes packet processing unit that performs processing of a received packet based on a processing rule set in advance or received from control device associated with the node. First control device among the control devices, in response to a predetermined trigger, refers to correspondence between forwarding nodes and control devices, and transmits, among forwarding path information, at least forwarding path information that includes a forwarding node associated with the first control device, to second control device associated with a forwarding node that is not associated with first control device, among forwarding nodes on a forwarding path of the received packet. Second control device generates and sends the processing rule to a forwarding node on the forwarding path, among forwarding nodes associated with the second control device, based on the forwarding path information.