Priority-Based Flow Control for Ring Topology Deadlock Prevention
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Solution Overview
Problem
Network systems with ring topologies face traffic flow control issues due to loops, leading to deadlock scenarios that prevent traffic flow while existing solutions like spanning trees result in decreased network utilization and increased latency.
Innovation Solution
Implementing priority-based flow control that combines shortest-path-first and spanning trees, where packets are routed based on priority using either spanning trees for lossless traffic to prevent deadlocks or shortest-path-first trees for best-effort traffic to maximize resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spanning trees are used to prevent deadlocks in ring topologies, then deadlock prevention is achieved, but network utilization decreases and latency increases
Solution Approach 1:
The patent segments traffic into different priority classes (lossless and best-effort traffic) and applies different forwarding tree strategies to each segment. Lossless traffic uses spanning trees for deadlock prevention, while best-effort traffic uses shortest-path-first trees for maximum utilization, thus resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent dynamically selects forwarding trees based on packet priority. The system adapts its behavior by choosing different forwarding strategies (spanning tree vs. shortest-path-first tree) depending on the traffic characteristics, enabling optimal performance for each traffic type while maintaining overall system reliability.
2Reliability
If spanning trees are used to prevent deadlocks in ring topologies, then deadlock prevention is achieved, but latency increases
Solution Approach 1:
The patent segments traffic into different priority classes and applies different forwarding strategies. Best-effort traffic uses shortest-path-first trees that minimize latency by taking optimal paths, while only lossless traffic uses spanning trees, thus reducing overall latency while maintaining deadlock prevention where necessary.
Solution Approach 2:
The system dynamically adjusts forwarding behavior based on traffic priority. By selecting shortest-path-first trees for best-effort traffic, the system minimizes transmission latency for time-sensitive applications while maintaining reliability for critical lossless traffic through spanning trees.
Data Source
AI summary
A system and method for priority-based flow control between nodes. In one example, pause deadlocks in a physical loop can be averted by priority-based selection of egress ports to which a packet is forwarded. In one embodiment, if the packet priority matches a configured lossless priority, then the set of internal egress ports is masked such that only the internal ports belonging to the spanning tree remain in the set of internal egress ports. If the packet priority does not match a configured lossless priority, then the set of internal egress ports is masked such that only the internal ports belonging to the shortest path first tree remain in the set of internal egress ports.