PCI Expansion Node Architecture for Bandwidth Scaling
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Solution Overview
Problem
Current information handling systems face limitations in expanding the number of PCI devices beyond the original system design, making it difficult to increase bandwidth and manage devices in PCI expansion chassis, which hampers diagnostic and inventory information access and device management.
Innovation Solution
The implementation of a primary PCI node with a first PCI switch communicatively coupled to a processor via a system interconnect, connected to multiple PCI devices, and a PCI expansion node via a PCI bus and sideband bus, enabling firmware to recognize and integrate additional PCI nodes, thus expanding the number of connected devices and managing them effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of PCI devices is increased beyond the original system design, then bandwidth and processing capability are improved, but device complexity and system architecture become more complex
Solution Approach 1:
The PCI system is divided into multiple hierarchical levels with root complexes at different tiers. The first PCI switch connects to a first root complex, while additional PCI devices connect to a second root complex that is itself connected to the first root complex via a PCI bus. This segmentation allows the system to scale beyond the original single root complex limitation, enabling increased bandwidth and device capacity while maintaining manageable complexity through modular architecture.
2Quantity of substance
If PCI expansion nodes are added to increase the number of connected devices, then device capacity is improved, but difficulty of detecting and measuring device status and inventory information increases
Solution Approach 1:
The system implements feedback mechanisms where the first root complex receives status and inventory information from both the first and second root complexes through the PCI bus connection. This feedback loop enables the first root complex to maintain awareness of all connected PCI devices across multiple expansion nodes, allowing for centralized diagnostic and inventory management despite the distributed architecture.
3Adaptability or versatility
If multiple PCI expansion nodes are interconnected to expand device capacity, then adaptability is improved, but device complexity increases
Solution Approach 1:
The PCI bus serves multiple functions simultaneously: it connects the first root complex to the second root complex, enables communication between expansion nodes, and provides a standardized interface for device attachment. This multi-functionality allows the same bus infrastructure to support both original and expanded PCI devices, providing adaptability and versatility without requiring separate specialized connection architectures for each expansion node.
Data Source
AI summary
An information handling system (IHS), peripheral component interface (PCI) system and method for expanding PCI nodes in an IHS. The PCI system includes a primary PCI node. The primary PCI node has a PCI switch communicatively coupled to a processor via a system interconnect. The PCI switch is communicatively coupled to several PCI devices. A communication module is communicatively coupled to the PCI switch. A PCI expansion node is communicatively coupled to the primary PCI node via a PCI bus and a sideband bus. The IHS executes firmware that enables expansion of the IHS by configuring the primary PCI node to recognize the one or more interconnected PCI expansion nodes and integrate the functions of the interconnected PCI expansion nodes into an expanded PCI subsystem. The primary PCI node and PCI expansion node can be substantially identical IHSs, having the same motherboards and chassis.