Virtual Network Function Chain Proof of Transit With WL-PT-ID

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Solution Overview

Problem

In Network Function Virtualization (NFV) environments, there is no effective way to guarantee that data packets traverse the correct Virtual Network Functions (VNFs) in a chain and determine the processing time, especially when VNFs are deployed as virtual machines or containers, and SRv6 proxies are involved, leading to operational blind spots.

Innovation Solution

Implement a path tracing mechanism using a Wide Local Path Tracing Identification (WL-PT-ID) to record path tracing information, which extends the data-plane to collect proof of transit data from NFV nodes, combined with a Software Defined Networking (SDN) controller for analytics, to determine the packet's trajectory and processing time through the NFV chain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Network Function Virtualization is used to virtualize network services on commodity hardware, then scalability and agility are improved, but there is no guarantee that steered packets go through the correct Virtual Network Functions in the NFV chain

Engineering Contradiction:

Improvescalability and agilityVSAvoidpacket transit guarantee

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism by embedding path tracing information in packet headers that loops back to the controller. The controller injects path tracing packets into the NFV chain, collects transit information from VNFs, and verifies whether packets followed the intended path. This closed-loop feedback system ensures reliability in packet transit while maintaining the flexibility of virtualized networks.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary path tracing mechanism that mediates between the controller and VNFs. The path tracing packet acts as an intermediary carrier that transports transit information through the NFV chain, enabling the controller to verify packet paths without direct intervention in the data plane forwarding decisions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of energy

If Virtual Network Functions are deployed as Virtual Machines or Containers for resource consolidation, then hardware costs are reduced, but operational visibility and tracking capability are lost

Engineering Contradiction:

Improvehardware costVSAvoidoperational visibility

Core Design Contradiction:

Loss of energyVSLoss of information

Solution Approach 1:

The patent replaces physical hardware-based network functions with virtualized software implementations while substituting traditional monitoring approaches with a software-based path tracing mechanism. The path tracing information embedded in packet headers provides operational visibility into virtualized NFV chains without requiring dedicated monitoring hardware, thus maintaining cost efficiency while recovering visibility.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the state of packet headers by embedding path tracing information as additional parameters. This allows the system to track packet paths through virtualized functions without altering the fundamental virtualized architecture, maintaining resource consolidation benefits while enabling detailed operational visibility through modified packet metadata.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If SRv6 proxies are used to steer packets through NFV chains, then network flexibility is improved, but it becomes impossible to detect whether packets traverse the correct chain or processing time

Engineering Contradiction:

Improvenetwork flexibilityVSAvoidpacket path detection

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by pre-configuring path tracing information in packet headers before packets enter the NFV chain. The controller prepares path tracing packets with embedded identifiers that will be recognized by VNFs, enabling detection of packet paths through the flexible SRv6-proxied network without adding complexity to the forwarding plane.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the network monitoring function from the data plane forwarding. Path tracing information is separated into distinct header fields that can be independently processed, allowing SRv6 proxies to maintain network flexibility while enabling separate verification of packet paths through the NFV chain.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12363005B2Virtual network function proof of transit

Publication Date: 2025.07.15 CISCO TECHNOLOGY INC

AI summary

Techniques for monitoring data transport in a network virtualization function (NVF) chain. A path tracing packet is generated having a Midpoint Compressed Data (MCD) to collect path tracing information of the NVF chain. The NVF node is configured to record an MCD containing Wide Local Path Tracing Identification (WL PT ID). The WL PT ID includes a first field having a value that indicates that a non-standard path tracing format is to be used and has a second field that indicates a particular path tracing format to be used. The path tracing packet is passed through the NVF chain and is then received back again after passing through the NVF chain. Data collected by the path tracing packet is analyzed to determine which NVF nodes the path tracing packet passed through, and the amount of time taken for the path tracing packet to pass through, the NVF chain.