VM Frame Transfer Scheduling for Low-Jitter Real-Time Communication

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Solution Overview

Problem

Existing communication systems between virtual machines in industrial and in-vehicle networks face challenges in achieving real-time performance due to delays caused by data copy and hypercall overhead, and synchronization issues when implementing IEEE 802.1Qbv with software switches.

Innovation Solution

A communication apparatus that separates data transfer and control information transfer, using a dedicated network for each virtual machine pair and a transfer control unit to manage frame timing based on IEEE 802.1Qbv schedule information, reducing data copy and hypercall operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If data transfer between virtual machines is implemented using software switches with hypercall mechanisms, then virtual machine isolation and flexibility are improved, but communication delay and jitter increase due to data copy overhead

Engineering Contradiction:
Improvevirtual machine isolationVSAvoidcommunication delay
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent segments the data transfer path by introducing dedicated physical network devices for each virtual machine pair, separating control plane (hypercall) from data plane (direct network transfer). This eliminates the need for data copying through software switches while maintaining virtual machine isolation through dedicated hardware paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dedicated physical network devices as intermediaries between virtual machines, replacing the software switch as the data transfer mediator. These dedicated devices handle frame transfer directly without requiring hypercall-mediated data copying, thus reducing communication delay while preserving virtual machine isolation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If IEEE 802.1Qbv scheduling is implemented through software switches, then frame timing control is improved, but synchronization accuracy deteriorates due to processing overhead

Engineering Contradiction:
Improveframe timing controlVSAvoidsynchronization accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent extracts the time-critical frame transfer function from the software switch and implements it in dedicated physical network devices. This separates the high-precision timing control function from the overhead-prone software environment, allowing IEEE 802.1Qbv scheduling to be executed with higher synchronization accuracy in hardware while the software switch retains only control plane functions.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If dedicated network devices are allocated for each virtual machine pair, then communication reliability is improved, but device complexity and resource utilization worsen

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidnetwork device allocation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple virtual machine communication pairs that share common physical network segments, allowing dedicated network devices to be shared among multiple VM pairs while maintaining isolation. This reduces overall device complexity and improves resource utilization compared to allocating exclusive devices to each VM pair, while still ensuring communication reliability through dedicated logical paths.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3822780B1Communication apparatus, communication method, and computer-readable medium
Publication Date: 2025.11.26 KK TOSHIBA
  • EP3822780B1 patent drawingFigure 1
  • EP3822780B1 patent drawingFigure 2
  • EP3822780B1 patent drawingFigure 3

AI summary

According to an arrangement, a communication apparatus (300) includes a writing unit (61), a transfer control unit (60), a descriptor receiving unit (64), and a reading unit (63). The writing unit (61) writes a frame in a first virtual storage area (52). The transfer control unit (60) controls a timing for transferring a descriptor of the frame based on schedule information. The descriptor receiving unit (64) receives the descriptor. The reading unit (63) that reads the frame from a second virtual storage area (56) specified based on the descriptor when the descriptor is received by the descriptor receiving unit (64).