Resilient Routing Algorithms for Split-Architecture Networks
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Solution Overview
Problem
Conventional split-architecture networks face challenges in network resilience and reliability due to the coupling of control and data planes, where link and switch failures can lead to significant data losses and network disruptions, as they do not adequately consider resilience factors in routing protocols.
Innovation Solution
The development of algorithms to generate a controller routing tree that balances distance and resilience, using methods like the Maximum Resilience (MR) and Resilience Aware Shortest Path (RASP) algorithms to establish backup paths between switches and controllers, ensuring network stability and minimizing the impact of failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional routing protocols are used in split-architecture networks, then the network structure is simple and easy to implement, but the network resilience is poor and data losses occur during failures
Solution Approach 1:
The patent pre-calculates and establishes backup paths between switches and controllers before failures occur. The routing protocol computes alternative routes in advance and configures them in the switching devices, so that when a failure happens, the network can immediately switch to the pre-prepared backup path without complex real-time calculations, thus improving resilience while keeping the failure response simple.
Solution Approach 2:
The patent introduces a backup path mechanism as an intermediary layer between the primary routing path and the failure state. When the primary path fails, traffic is redirected through this intermediary backup path to reach the controller, preventing direct failure impact and maintaining network resilience without requiring complex real-time rerouting decisions.
2Reliability
If backup paths are established between switches and controllers, then network resilience is improved, but the routing complexity and computational overhead increase
Solution Approach 1:
The routing protocol performs backup path calculations in advance during normal operation periods when network conditions are stable. By pre-computing and storing backup routes before failures occur, the system avoids time-consuming real-time calculations during failure events, thus improving control plane reliability while minimizing the time loss associated with routing decisions.
Solution Approach 2:
The routing protocol autonomously calculates and configures backup paths without requiring manual intervention or complex external coordination. The system self-manages the backup path computation and updates the switching devices automatically, reducing the time overhead associated with manual configuration and simplifying the overall routing management process.
3Reliability
If control and data planes are coupled in conventional architecture, then the network management is simplified, but the control traffic and data traffic are equally affected when failures occur
Solution Approach 1:
The patent implements a split-architecture design that segments the network into separate control plane and data plane components. Control traffic between switches and controllers is routed through dedicated backup paths, while data traffic follows separate forwarding paths. This segmentation ensures that failures in one plane do not necessarily affect the other, improving control traffic reliability while maintaining manageable architecture through clear separation of concerns.
Data Source
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AI summary
The invention is a routing algorithm characteristic that minimizes the weight, meaning that the probability that a node is disconnected from the controller in case of a failure in the network is minimized. The first algorithm used in the invention is an approximation algorithm for finding the controller routing tree that provides maximum resilience in the network. The algorithm is referred to herein as the Maximum Resilience (MR) algorithm. The heuristic MR algorithm selects a shortest-path tree as a starting point and modifies the tree in order to improve resilience. The output of the MR algorithm is not necessarily a shortest-path tree, but provides more resilience compared to the initial tree. The RASP algorithm provides a shortest-path tree with improved network resilience compared to other possible shortest-path trees.