OpenFlow Switching Node Traffic Recovery via Backup Path Association
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Solution Overview
Problem
OpenFlow networks lack effective mechanisms for scalable and rapid traffic recovery, particularly in scenarios requiring high network reliability, as existing solutions rely on full-state controllers and extensive communication between nodes, which limits scalability and increases recovery time.
Innovation Solution
The method involves configuring backup paths in OpenFlow networks by associating flow entries for backup paths with those of working paths, allowing automatic switching to backup paths upon failure, and using periodic renewal packets to maintain backup path entries without requiring a full-state controller, thus reducing communication overhead and enabling quicker response to failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a full-state controller is used to enable fast recovery in OpenFlow networks, then recovery speed is improved, but device complexity and communication overhead increase significantly
Solution Approach 1:
The patent segments the controller functionality by introducing distributed controller agents at switching nodes that independently manage local backup path configurations. This eliminates the need for a centralized full-state controller while maintaining fast recovery capability through localized failure detection and response mechanisms.
Solution Approach 2:
Switching nodes are empowered with self-service capabilities to detect failures locally and automatically activate backup paths without requiring controller intervention. The system performs its own failure detection and recovery operations, reducing dependency on complex centralized control.
2Reliability
If extensive communication between nodes is implemented for failure detection and recovery, then recovery accuracy is improved, but communication overhead increases
Solution Approach 1:
The patent implements local quality by enabling each switching node to independently detect failures in its local network segment without requiring global communication. Each node monitors its own incoming and outgoing traffic patterns to identify failures, minimizing communication overhead while maintaining accurate failure detection.
3Device complexity
If backup path flow entries are maintained without renewal mechanisms, then device complexity is reduced, but flow entries expire and recovery capability is lost
Solution Approach 1:
The patent implements periodic action through flow entry renewal packets that are periodically transmitted along backup paths to refresh and extend the lifetime of backup flow entries. This ensures backup paths remain available without requiring complex continuous management mechanisms.
Solution Approach 2:
The system uses feedback mechanisms where switching nodes monitor the usage and validity of backup flow entries, and automatically initiate renewal processes when entries approach expiration. This feedback loop maintains backup path availability while keeping management complexity minimal.
4Speed
If working path flow entries are associated with backup path flow entries, then switching speed is improved, but flow table complexity increases
Solution Approach 1:
The patent merges the management of working and backup path flow entries by establishing associations between them. When a failure is detected, the system quickly switches from the working path entry to the associated backup path entry, enabling rapid path switching while maintaining a relatively simple flow table structure through the association mechanism.
Data Source
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AI summary
Traffic recovery is supported at a switching node (20) of an OpenFlow network (5).The switching node (20) has a flow table (23) for storing flow entries (24) which determine forwarding of received packets between the ports. A switching node (20) installs (102) a flow entry for a back up path in the flow table (23). The switching node (20) renews (104, 105) the flow entry for the backup path based on at least one of : (i) an association between the flow entry for the backup path and a flow entry for a working path at the switching node, wherein the flow entry for the backup path is renewed when the flow entry for the working path is used to forward a received packet; (ii) receiving a flow entry renewal packet from another switching node on the backup path. A backup path can be configured for each of multiple points of failure in the working path.