Network Path Probing in DSFs with Deterministic Fabric Headers

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Solution Overview

Problem

Conventional Disaggregated Scheduled Fabrics (DSFs) lack mechanisms for deterministic path selection and probing, leading to challenges in measuring Quality of Service (QoS) parameters for individual network paths due to random data packet spraying.

Innovation Solution

A system and method for deterministic path selection and probing in DSFs, utilizing a path probing logic to select network paths, construct fabric headers, and transmit probe packets with fabric headers that include identifiers for adjacent devices and ports, enabling QoS parameter measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If data packets are randomly sprayed over multiple network paths in conventional DSFs, then network load is distributed and scalability is improved, but QoS parameter measurement for individual paths becomes impossible

Engineering Contradiction:
Improvenetwork scalabilityVSAvoidQoS parameter measurement
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the network path identification by introducing fabric headers that contain path identification fields. Each probe packet is segmented with specific header information that identifies its traversed path, enabling individual path QoS measurement while maintaining the overall random spraying architecture for scalability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fabric header acts as an intermediary carrier that bridges the gap between random packet spraying and deterministic path measurement. It contains path identification information that mediates between the distributed routing mechanism and the QoS measurement requirement, allowing path-specific monitoring without changing the underlying random spray architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If conventional networks use predetermined network paths for data transmission, then QoS parameter measurement is straightforward, but network scalability and load distribution are limited

Engineering Contradiction:
ImproveQoS parameter measurementVSAvoidnetwork scalability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic path selection capabilities where probe packets can be deterministically routed through specific paths using fabric headers, while data packets continue to use random spraying. This dynamic approach allows flexible adaptation between predetermined paths for measurement and random paths for scalability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by making path identification and measurement capability available locally at each network node through fabric header processing. Each switch can independently identify and measure QoS for specific paths passing through it, enabling localized path measurement without imposing global predetermined routing constraints.

Inventive Principle:
Principle #3Local quality

3Reliability

If probe packets are transmitted dynamically to monitor network changes, then real-time network health monitoring is achieved, but the complexity of path identification and tracking increases

Engineering Contradiction:
Improvenetwork health monitoringVSAvoidpath identification complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-populating fabric headers with path identification information before probe packets enter the network. This preliminary tagging of packets with their intended paths simplifies subsequent tracking and measurement at each network node, reducing the complexity of real-time path identification while maintaining reliable monitoring.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If multiple probe packets are transmitted to measure QoS parameters, then comprehensive network performance assessment is achieved, but the overhead of probe transmission and processing increases

Engineering Contradiction:
ImproveQoS parameter assessmentVSAvoidprobe transmission overhead
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The fabric header serves multiple functions: it identifies the network path, carries QoS measurement information, and enables deterministic routing of probe packets. This multi-functionality reduces the need for separate mechanisms for each function, thereby reducing overall probe transmission overhead while maintaining comprehensive QoS assessment capabilities.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4611337A1A method for probing network paths in disaggregated scheduled fabrics and a system thereof
Publication Date: 2025.09.03 CISCO TECHNOLOGY INC
  • EP4611337A1 patent drawingFigure 1
  • EP4611337A1 patent drawingFigure 2
  • EP4611337A1 patent drawingFigure 3

AI summary

Devices, networks, systems, methods, and processes for probing a network path in a Disaggregated Scheduled Fabric (DSF) are described herein. A source device, such as a first leaf switch can receive a probe command and identify a network path associated with the probe command. The first leaf switch may generate, based on the probe command, a probe packet comprising a fabric header. The first leaf switch can identify an adjacent device such as a spine switch and transmit the probe packet to the spine switch. The spine switch can forward the probe packet to a destination device, such as a second leaf switch. The second leaf switch may generate and transmit a response probe packet in response to the probe packet. The probe packet can be utilized to measure one or more Quality of Service (QoS) parameters such as jitter, latency, packet loss, or congestion etc. for example.