External Probe Packet Path Tracing for ECMP-Consistent Network Flows

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Solution Overview

Problem

Existing path tracing technologies face challenges in scaling to handle rapid probe generation rates and maintaining accurate traffic flow monitoring across networks, particularly in environments where entities desire to use their own external probing appliances to generate and consume probe packets, necessitating proper encapsulations that match typical traffic flows.

Innovation Solution

An external probing appliance generates probe packets with a packet tracing indication in the next header field, triggering proxy-source and proxy-sink behaviors at network nodes, using encapsulations that match regular traffic data, and collects path tracing data without requiring special SRv6 SIDs, thereby maintaining consistent ECMP paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If path tracing is implemented using existing technologies, then path tracing capability is provided, but hardware load increases and probe generation rate is limited

Engineering Contradiction:
Improveprobe generation rateVSAvoidhardware load
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces an external probing appliance as an intermediary device that generates and processes probe packets outside the network core. This mediator handles the complex path tracing operations externally, reducing the hardware load on network devices while enabling high-rate probe generation through dedicated probing infrastructure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The path tracing functionality is extracted from the network core devices and relocated to an external probing appliance. By taking out the probe generation and processing functions from the network infrastructure, the patent reduces hardware load on network devices while maintaining high probe generation rates through specialized external equipment.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If external probing appliances are used to generate probe packets, then probe generation flexibility is improved, but proper encapsulation to match traffic flows becomes complex

Engineering Contradiction:
Improveprobe generation flexibilityVSAvoidencapsulation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent copies the encapsulation format of regular traffic packets for the probe packets. By using the same encapsulation structure as actual data traffic, the external probing appliance can generate probes that naturally follow the same ECMP paths as user traffic without requiring complex special-purpose encapsulations, thus maintaining flexibility while simplifying the process.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The probe packets are designed with universal encapsulation that matches regular traffic flows. This universal format allows the external probing appliance to generate probes that can traverse any ECMP path used by user traffic, providing adaptability across different network scenarios without requiring protocol-specific or path-specific modifications.

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

3Reliability

If probe packets use special SRv6 SIDs for path tracing, then path tracing functionality is enabled, but ECMP path consistency with traffic flows is compromised

Engineering Contradiction:
Improvepath tracing accuracyVSAvoidECMP path consistency
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies homogeneity by making probe packets identical in encapsulation to regular traffic packets. Both use the same format without special SRv6 SIDs, ensuring that probes and traffic flows are treated equally by ECMP routing algorithms. This homogeneity guarantees that probes follow the exact same paths as user traffic, maintaining both path tracing accuracy and ECMP path consistency.

Inventive Principle:
Principle #33Homogeneity

Data Source

PatentEP4661359A1Path tracing proxy behaviour for integration with external probing appliance
Publication Date: 2025.12.10 CISCO TECHNOLOGY INC
  • EP4661359A1 patent drawingFigure 1
  • EP4661359A1 patent drawingFigure 2
  • EP4661359A1 patent drawingFigure 3

AI summary

Systems, methods, and computer-readable media are provided for path tracing proxy behavior using an external probing appliance. An example method can include generating, at an external probing appliance of a network, a probe packet, the probe packet including a source address, a destination address, and a packet tracing indication in a next header field of the probe packet, the packet tracing indication triggering a proxy source behavior at a source node having the source address and a proxy sink behavior at a sink node having the destination address; sending the probe packet to the source node to trigger a packet tracing mechanism; and receive an updated probe packet from the sink node, the updated probe packet including probe data associated with one or more data flows in the network as the one or more data flows traverse the network from the source node to the sink node.