SDN Path Switching via Segmented Detection and Intermediary Packets
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Solution Overview
Problem
The OpenFlow protocol lacks a solution for path failures in software-defined networks (SDNs), leading to communication interruptions when a path failure occurs, as it only detects electric failures on individual ports and does not provide a mechanism for switching to a standby path.
Innovation Solution
A path switching method and device that determine an active path and standby paths with the same source and destination switches, deliver a flow table to a standby path switch, and use a path group table to switch data flows from an active path to a standby path when a failure is detected, ensuring continuous communication by selecting a standby port for data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OpenFlow protocol uses fast failover group table for port failure detection, then port-level failure switching is achieved, but path-level failure detection and switching capability is lost
Solution Approach 1:
The patent segments the failure detection function into two layers: port-level detection using existing fast failover group tables at each switch, and path-level detection using end-to-end detection packets traversing multiple switches. This segmentation allows each layer to handle its specific detection scope while working together to achieve comprehensive path failure detection and switching capability.
2Reliability
If OpenFlow protocol implements path failure detection mechanism, then communication continuity is maintained, but system complexity increases
Solution Approach 1:
The patent introduces detection packets as intermediaries that traverse the network path to carry failure detection information. These packets act as mediators between the source and destination switches, enabling path failure detection without requiring complex direct communication mechanisms between all network components. The detection packets simplify the overall system complexity while maintaining communication continuity.
3Ease of operation
If switch detects only electric failure of its own port, then local failure response is achieved, but network path failure detection is insufficient
Solution Approach 1:
The patent implements a feedback mechanism where detection packets are sent from the source switch through the network path to the destination switch, which then returns acknowledgment packets. This feedback loop provides continuous information about the health of the entire network path, enabling the source switch to detect path failures even when individual switches can only monitor their own ports locally.
Data Source
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AI summary
Embodiments of the present invention provide a path switching method and a device, including: determining, by a controller, an active path and at least one standby path of a data flow, and delivering a flow table to a standby path switch, so that after the data flow is switched from the active path to the standby path, the standby path switch forwards the data flow according to the flow table; and delivering, by the controller, a path group table to each failover switch, where the path group table includes an identifier of the active path and standby port information, so that when detecting, according to the identifier of the active path, that the active path encounters a failure, each failover switch performs path switching according to the standby port information. By means of such a path-level failure detection and switching that is performed after a failure occurs, the method can more effectively ensure transmission stability and efficiency of a data flow.