SDN Controller Tree Recovery Using Stored Topology
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Solution Overview
Problem
Software-defined networks (SDNs) face challenges in effective failure recovery, particularly in maintaining transmission quality when links or nodes disconnect, as existing methods often require broadcasting control messages to find new paths, which is inefficient.
Innovation Solution
A tree recovery method and controller that utilize stored topology information to classify nodes as losing or remaining and calculate new links, allowing for efficient reconnection without broadcasting control messages, using a processor to establish and update topology information and notify nodes for configuration changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional failure recovery methods are used in SDN, then network connectivity can be restored, but control messages need to be broadcasted to find new paths which reduces efficiency
Solution Approach 1:
The patent pre-calculates and stores alternative paths and topology information in the SDN controller before failures occur. When a link failure is detected, the controller immediately has recovery paths ready, eliminating the need for broadcast messages and enabling instant restoration of connectivity, thus resolving the contradiction between reliability and productivity.
2Reliability
If control messages are broadcasted to find new paths after failure, then network nodes can be reconnected, but the transmission time is increased
Solution Approach 1:
Alternative routing paths are pre-computed and stored in the controller's topology database before failures occur. Upon detecting a link failure, the controller immediately retrieves and activates the pre-calculated alternative path, bypassing the time-consuming broadcast process entirely and achieving instantaneous reconnection.
Solution Approach 2:
The SDN controller acts as an intermediary that maintains a centralized topology database and pre-computed alternative paths. When failures occur, the controller mediates the recovery process by directly instructing relevant switches to use alternative paths, eliminating the need for distributed broadcast messaging and reducing recovery time.
3Measurement precision
If the SDN controller uses stored topology information to calculate new links, then the lowest cost path can be found accurately, but the controller needs to maintain and update topology information
Solution Approach 1:
The SDN controller performs multiple functions: it maintains the topology database, pre-calculates alternative paths, detects failures, and manages switch configurations. By consolidating these diverse functions in a single centralized controller, the system achieves accurate path calculation without distributing the complexity across multiple nodes.
Solution Approach 2:
The controller serves as an intermediary that centralizes topology information management. It maintains an accurate view of the network topology and uses this information to compute optimal alternative paths, thereby achieving measurement precision while managing the complexity centrally rather than distributedly.
Data Source
AI summary
A tree recovery method for a software-defined network (SDN) adapted to an SDN controller is provided. The tree recovery method includes: establishing topology information based on a current SDN topology and storing the topology information in a storage of the SDN controller; receiving a failure message reporting a failure link of the SDN, a plurality of network nodes of the topology information are classified into at least one losing nodes and at least one remaining node according to the failure link; and calculating and linking the at least one losing node to the at least one remaining node by using the topology information stored in the storage.