Stateful Flow Tables for SDN Controller Load Reduction
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Solution Overview
Problem
Current OpenFlow-based software-defined networks (SDNs) are inefficient for state-dependent data forwarding due to their stateless forwarding rules, leading to increased burden on controllers and lack of support for use cases like state-dependent firewalls, link aggregation, and bandwidth capping, resulting in suboptimal resource utilization and scalability issues.
Innovation Solution
Implementing a method for locally-managed data forwarding in SDNs that packages state information with data packets and uses state machine logic to determine the next destination and actions within forwarding entities, allowing for state-dependent forwarding decisions without relying on controllers, and extending OpenFlow protocol to include stateful flow tables for tracking and updating state information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If stateless forwarding rules are used in OpenFlow, then forwarding decisions can be made at the forwarding entity, but state-dependent operations cannot be performed and all state-dependent frames must be sent to the controller
Solution Approach 1:
The patent segments the forwarding entity's capabilities into stateless forwarding (handled by traditional flow tables) and state-dependent forwarding (handled by new stateful flow tables). This allows the system to maintain efficient stateless forwarding while adding state-dependent capabilities where needed, rather than requiring all forwarding to be stateful.
Solution Approach 2:
The patent adds a new dimension to the flow table structure by introducing stateful flow tables that track state information across multiple frames. This extends the traditional stateless flow table model into a new dimension that incorporates state tracking, enabling state-dependent operations without abandoning the efficient stateless model.
2Adaptability or versatility
If all frames are sent to the controller for state-dependent processing, then state-dependent operations can be performed, but controller resource burden increases and efficiency decreases
Solution Approach 1:
The patent applies local quality by enabling state-dependent processing only at the forwarding entity where state information is locally tracked, rather than requiring all frames to be sent to the remote controller. This allows state-dependent operations to be performed locally at the FE level, maintaining efficiency while providing the needed functionality.
Solution Approach 2:
The forwarding entity performs state-dependent forwarding operations itself using locally-tracked state information, rather than relying on the controller to process every frame. This self-service capability reduces the controller's burden and improves overall system efficiency while maintaining state-dependent functionality.
3Adaptability or versatility
If state information is tracked at the controller, then state-dependent forwarding can be implemented, but the controller must handle more packets and track more data flows
Solution Approach 1:
The patent extracts the state tracking functionality from the controller and places it at the forwarding entity. This extraction reduces the controller's resource requirements and complexity by eliminating the need for the controller to track state information for all data flows, while still enabling state-dependent operations at the network edge.
4Adaptability or versatility
If external components are added to the OpenFlow switch for state-dependent operations, then specific use cases can be supported, but resource utilization becomes non-optimal due to redundant functionality
Solution Approach 1:
The patent creates a universal stateful flow table mechanism that can support multiple state-dependent use cases (firewall, LAG, OAM, APS, load balancing, bandwidth capping) within a single unified framework at the forwarding entity. This eliminates the need for separate external components for each use case, reducing redundancy and improving resource utilization while maintaining versatility.
Data Source
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AI summary
A method for forwarding a data flow of multiple data packets according to a protocol adapted for locally-managed data forwarding in a software-defined networking (SDN) architecture includes entering each data packet of the data flow of multiple data packets to a data communication forwarding entity(FE). At the forwarding entity, the next destination of the data packet is selected by applying state machine logic to at least one field of the data packet and to state information tracked by the forwarding entity before the data packet is received. The state machine logic includes rules for forwarding the data packet.