OpenFlow Node Barrier Synchronization for Flow Entry Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
OpenFlow communication systems experience delays in setting, changing, or deleting flow entries, leading to unintended packet forwarding paths due to communication delays between OpenFlow controllers and switches, which can result in incorrect processing rules being executed.
Innovation Solution
A communication system where nodes process packets based on retrieved processing rules from a control device, using identifiers to match packet information and prevent unintended actions by verifying the matching rule and processing rule alignment through additional verification information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the OpenFlow controller sets flow entries in multiple nodes, then the packet forwarding path is established, but communication delay occurs between the controller and switches causing unintended actions to be executed
Solution Approach 1:
The patent applies preliminary action by having the controller send a barrier message to nodes before sending flow entry setting messages. This barrier message prepares the nodes to receive and process subsequent flow entries in a controlled sequence, ensuring that flow entries are set correctly even during delays. The barrier message acts as a preliminary signal that synchronizes the nodes' readiness state before the actual flow entry configuration begins.
Solution Approach 2:
The patent implements feedback through the barrier reply mechanism. When the controller sends a barrier message, it waits for barrier replies from the nodes to confirm that the nodes have processed the barrier signal and are ready for flow entry setting. This feedback loop ensures that the controller has verification that nodes are in the correct state before proceeding, preventing unintended actions caused by premature or out-of-order flow entry application.
2Reliability
If the controller uses Barrier Request/Reply to ensure flow entry setting completion, then execution accuracy is improved, but the time before user packet transmission increases
Solution Approach 1:
The barrier message serves as a preliminary action that prepares nodes in advance for flow entry setting. By sending the barrier message first and having nodes prepare their state beforehand, the actual flow entry setting can proceed more efficiently once the nodes are ready, reducing the overall time impact compared to waiting for confirmation after each individual flow entry setting attempt.
Solution Approach 2:
The patent introduces dynamic control through the barrier mechanism, where the controller can adapt the flow entry setting process based on node readiness states. The barrier message and reply create a dynamic synchronization point that allows the system to adjust the timing and sequence of flow entry setting operations, optimizing the balance between reliability and speed based on actual network conditions.
3Productivity
If flow entries are set in relay switches, then packet forwarding is enabled, but conflicting flow entries cause packets to be forwarded to incorrect ports
Solution Approach 1:
The barrier message prepares relay switches in advance to receive and process flow entries in a controlled manner. This preliminary preparation ensures that when flow entries are subsequently sent to relay switches, they are processed in the correct sequence and with proper timing, preventing conflicts between competing flow entries and ensuring accurate packet forwarding to the intended ports.
Solution Approach 2:
The barrier reply mechanism provides feedback to the controller that the relay switch has successfully processed the barrier message and is ready for flow entry setting. This feedback ensures that flow entries are applied only when the relay switch is in the correct state, preventing situations where conflicting flow entries might be applied out of order or to an improperly prepared switch state, thereby maintaining flow entry matching accuracy.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention provides a configuration that prevents unintended processing, which may be generated due to a delay in setting a processing rule (flow entry), from being executed in a node arranged in a data forwarding network. A communication system includes a node that processes a received packet; and a control device that sets a processing rule, which defines a matching rule and processing for a packet that conforms to the matching rule, in the node. The node holds an identifier in association with a processing rule and determines whether or not to perform processing for a received packet depending upon whether or not an identifier of the received packet corresponds to an identifier associated with a processing rule corresponding to a matching rule that conforms to the received packet, wherein the processing is performed according to the processing rule corresponding to the matching rule that conforms to the received packet.