PCIe Switching Device With Port Agent Bus Number Sharing

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Solution Overview

Problem

The conventional PCIe system is limited by 256 bus numbers, restricting the quantity of PCIe devices that can be supported.

Innovation Solution

A PCIe switching device with a port agent apparatus that shares a bus number among multiple downstream ports, reducing the number of bus numbers required and increasing the capacity of the PCIe system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If each downstream port is assigned a unique bus number, then device identification is straightforward, but the quantity of supported PCIe devices is limited to 256

Engineering Contradiction:

Improvequantity of supported PCIe devicesVSAvoidbus number management complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent introduces a PCIe switching device as an intermediary component between the processor and multiple PCIe endpoint devices. The switch contains a port agent apparatus that manages bus numbers for multiple downstream ports, allowing more than 256 devices to be supported by mediating the bus number allocation and sharing among ports.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent merges multiple downstream ports under a single bus number management domain through the port agent apparatus. Instead of requiring unique bus numbers for each downstream port, multiple ports can share or dynamically allocate bus numbers, effectively combining their resource management under one controller to exceed the 256-device limit.

Inventive Principle:

Principle #5Merging (Combining)

2Quantity of substance

If multiple PCIe domains are introduced to support more devices, then device capacity increases, but system complexity and compatibility requirements increase

Engineering Contradiction:

Improvequantity of supported PCIe devicesVSAvoidcompatibility with existing BIOS, OS, and drivers

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The PCIe switching device acts as an intermediary that transparently handles multi-domain device connections while presenting a unified interface to the processor. The port agent apparatus manages bus number allocation across multiple domains internally, but external systems (BIOS, OS, drivers) continue to interact with a simplified single-domain model, maintaining compatibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the PCIe system into multiple functional domains managed by the switching device, where the port agent apparatus handles complex bus number management internally. This segmentation allows the system to support more devices through multiple domains while keeping the interface to external systems simple and compatible with existing software.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12450187B2Method for expanding PCIe system, PCIe switching device, and PCIe system

Publication Date: 2025.10.21 HUAWEI TECH CO LTD

AI summary

A PCIe switching device includes an upstream port, a port agent apparatus, and a plurality of first downstream ports. The upstream port is connected to the port agent apparatus, which is connected to the plurality of first downstream ports. Each first downstream port is configured to connect to a PCIe endpoint device. Links between the plurality of first downstream ports and PCIe endpoint devices connected to the plurality of first downstream ports share a same bus number.