Network Switch Congestion Indication Marking for Flow Re-routing
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Solution Overview
Problem
Existing communication networks face challenges in mitigating congestion spreading, particularly when a switch becomes overloaded, leading to performance degradation across the network due to flow-control backpressure and congestion spreading to upstream switches.
Innovation Solution
The implementation of a network switch with switching circuitry that marks outbound packets with congestion indications based on the occupancy of Virtual Lanes (VLs) and flow-control credits from downstream switches, allowing for the re-routing of data flows to avoid congested paths by classifying flows as contributor or victim flows and assigning suitable VLs to prevent congestion spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flow control measures are employed to prevent buffer overflow, then buffer overflow is prevented, but congestion spreads to upstream switches
Solution Approach 1:
The patent segments the network traffic into multiple Virtual Lanes (VLs) and implements separate congestion control for each VL. By marking packets with per-VL congestion indications, the system can identify and redirect only the victim flows that are suffering from congestion, while allowing contributor flows to continue at full rate. This segmentation prevents congestion spreading to upstream switches by isolating the problematic flows.
Solution Approach 2:
The patent applies local quality by treating different Virtual Lanes differently based on their congestion state. Victim flows receive special handling through redirection to alternative VLs, while contributor flows maintain normal transmission. This localized differentiation allows the system to address congestion for specific flows without affecting the entire network or upstream switches.
2Reliability
If congestion control strategies are implemented to resolve congestion, then congestion is mitigated, but network performance degrades due to upstream buffer overflow
Solution Approach 1:
The patent implements preliminary action by proactively marking packets with congestion indications before they cause buffer overflow at upstream switches. The congestion root indicator is set in advance based on current queue occupancy and flow control credits, allowing source nodes to redirect victim flows before congestion propagates upstream, thereby maintaining network performance.
Solution Approach 2:
The patent uses feedback mechanisms where downstream switches monitor queue occupancy and flow control credits to determine congestion state. This information is fed back to source nodes through marked packets, enabling dynamic flow redirection. The feedback loop allows the network to adapt to changing congestion conditions and maintain optimal performance.
3Adaptability or versatility
If packets are marked with congestion indications for flow re-routing, then victim flows can be redirected, but device complexity increases
Solution Approach 1:
The patent changes parameters by introducing congestion indication fields in packet headers and modifying queue management parameters based on VL-specific congestion state. The switching circuitry monitors queue occupancy and flow control credits to dynamically adjust packet marking and routing decisions. This parameter-based approach enables flow re-routing without requiring complex structural changes to the switch architecture.
Data Source
AI summary
A network switch includes switching circuitry and multiple ports. The multiple ports are connected to a communication network. The switching circuitry is configured to receive via the ports packets that are assigned respective Virtual Lanes (VLs), and forward each packet for transmission via a respective selected port, to queue the packets pending for transmission via a given port in multiple VL-dedicated queues, in accordance with the VLs assigned to the packets, to mark an outbound packet, pending for transmission via the given port, with multiple congestion indications that are indicative of respective congestion states of the multiple VL-dedicated queues of the given port, and to transmit the marked outbound packet via the given port.