Trace Policy Engine for SDN Packet Troubleshooting

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Solution Overview

Problem

In Software Defined Networking (SDN) networks, tracing packets becomes complex due to the intricate packet processing pipelines, leading to difficulties in troubleshooting, especially when packets deviate from their intended paths, and existing techniques either cause operational issues or consume excessive resources and bandwidth.

Innovation Solution

A system comprising a switch with a packet processing pipeline, an SDN controller, and a trace policy engine that sets up a trace infrastructure, enables tracing for packets belonging to specific flows, collects and analyzes trace messages to determine traversal paths and flow tables, and stores analysis results, thereby facilitating effective troubleshooting without causing operational issues or excessive resource consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If packet tracing is enabled in SDN networks with complex packet processing pipelines, then troubleshooting capability is improved, but system complexity and resource consumption increase

Engineering Contradiction:
Improvetroubleshooting capabilityVSAvoidsystem complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent introduces a trace policy engine as an intermediary component between the SDN controller and the packet processing pipeline. This engine selectively enables tracing only for specific flows that need troubleshooting, rather than enabling comprehensive tracing across all packets. The trace policy engine receives tracing requests, determines which flows should be traced based on policy criteria, and configures the packet processing pipeline accordingly, thereby reducing overall system complexity while maintaining improved troubleshooting capability for critical flows.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies local quality by enabling tracing functionality selectively for specific flows rather than uniformly across all packets. The trace policy engine identifies particular flows that require troubleshooting and applies tracing only to those flows based on matching criteria such as source/destination IPs, ports, or protocol types. This localized approach improves troubleshooting capability where needed while avoiding the resource consumption and complexity overhead of global tracing.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If comprehensive packet tracing is implemented across all flows, then troubleshooting accuracy is improved, but resource consumption and bandwidth usage increase

Engineering Contradiction:
Improvetroubleshooting accuracyVSAvoidresource consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements partial action by enabling tracing only for specific flows that match predetermined policy criteria, rather than tracing all packets. The trace policy engine evaluates each flow against configured criteria (such as source/destination addresses, port numbers, or protocol types) and enables tracing only when the criteria are met. This partial tracing approach maintains high troubleshooting accuracy for relevant flows while significantly reducing resource consumption compared to comprehensive tracing of all packets.

Inventive Principle:
Principle #16Partial or excessive action

3Adaptability or versatility

If tracing is enabled for multiple flows simultaneously, then troubleshooting coverage is improved, but operational issues and system overhead increase

Engineering Contradiction:
Improvetroubleshooting coverageVSAvoidoperational stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies dynamics by making the tracing configuration adaptive and changeable based on operational needs. The trace policy engine allows dynamic addition, modification, or removal of tracing policies for different flows without requiring system reconfiguration or downtime. Administrators can update flow matching criteria, enable/disable tracing for specific flows, or adjust policy parameters in real-time based on emerging troubleshooting requirements, thereby maintaining both broad troubleshooting coverage and operational stability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3879759B1Optimized datapath troubleshooting with trace policy engine
Publication Date: 2023.09.13 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3879759B1 patent drawingFigure 1
  • EP3879759B1 patent drawingFigure 2
  • EP3879759B1 patent drawingFigure 3

AI summary

A system for tracing packets in a Software Defined Networking (SDN) network is described. The system includes a switch that includes a packet processing pipeline, an SDN controller communicatively coupled to the switch and a trace policy engine communicatively coupled to the SDN controller. The trace policy engine is configured to cause the SDN controller to set up a trace infrastructure in the switch, cause the SDN controller to enable tracing at the switch for packets belonging to a flow in response to a determination as at least one of a user-request to trace the packets belonging to the flow and a packet belonging to the flow has been dropped, collect trace messages for the packets belonging to the flow, analyze the trace messages for the packets belonging to the flow to determine at least one of a traversal-path of packet; and a flow-table of the packet processing pipeline of the switch at which packets are being dropped, and store a result of the analysis.