SDN Controller Flow Path Detection via TTL Reports
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Solution Overview
Problem
In SDN hybrid networks, controllers cannot accurately calculate the message forwarding path between subscriber hosts due to conventional routing protocols, limiting their ability to monitor the network effectively.
Innovation Solution
A flow path detecting method where the controller issues reporting indication information to forwarding devices to report message forwarding information, constructing a detection message with specific features, and sorting the received information by TTL values to determine the forwarding path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional routing protocols are used in SDN hybrid networks, then forwarding paths are automatically determined by routing protocols, but controllers cannot accurately calculate or monitor the message forwarding path between subscriber hosts
Solution Approach 1:
The patent introduces detection messages as intermediary elements that traverse the network path. These messages carry identification information and TTL values, enabling the controller to indirectly trace the forwarding path through reports from intermediate forwarding devices without requiring direct path calculation capability
Solution Approach 2:
The patent implements a feedback mechanism where forwarding devices report detection message information back to the controller. This feedback loop provides the controller with path information that would otherwise be inaccessible, resolving the contradiction between automatic routing and controller visibility
2Loss of information
If the controller issues detection messages to all forwarding devices, then complete path information can be obtained, but network traffic and controller processing load increase
Solution Approach 1:
The patent applies preliminary action by setting the TTL value of detection messages to match the expected maximum path length. This prevents detection messages from traversing unnecessary network segments, reducing redundant traffic while ensuring complete path information is captured within the intended scope
Solution Approach 2:
The patent uses parameter changes by dynamically adjusting the TTL value of detection messages based on network topology and expected path lengths. This optimization balances information completeness with resource consumption by tuning the detection message propagation range
Data Source
AI summary
Provided is a flow path detection method. The method comprises: a controller in an SDN network issuing reporting indication information to a forwarding device in the SDN network, wherein the reporting indication information is used for instructing the forwarding device to report, when receiving a message matching a pre-determined message feature, message forwarding information corresponding to the message, and the pre-determined message feature comprises: a source IP address and a destination IP address of a detection message for detecting a path, and a controller identifier of a controller; the controller receiving the message forwarding information reported by a plurality of forwarding devices according to the reporting indication information; and according to the received message forwarding information reported by the plurality of forwarding devices, determining a forwarding path between the source IP address and the destination IP address for the detection message.