Chapter 2 PEX 8532 Applications
2.1
Multi-Purpose and Feature-Rich PCI Express Switch
The ExpressLane PEX 8532 device offers PCI Express switching capability, conforming to the
PCI Express Base r1.0a, enabling users to add scalable, high-bandwidth, non-blocking interconnection
to a wide variety of applications including servers, storage systems, communications platforms, blade
servers, and embedded-control products. The PEX 8532 switch can be used as fan-out, aggregation, or
peer-to-peer switching, and is equally well-suited for fabric backplane and intelligent I/O module
applications.
2.1.1
2.1.2
End-to-End Packet Integrity
The PEX 8532 provides End-to-end CRC (ECRC) protection and Poison-Bit support to enable designs
that require guaranteed error-free packets. These features are optional in the PCI Express Base r1.0a;
however, PLX provides them across its entire ExpressLane switch product line.
PCI Express Switch Non-Transparent Bridging (NTB)
The PEX 8532 supports full Non-Transparent bridging (NTB) functionality to allow implementation of
multi-host systems and intelligent I/O modules in applications such as communications, storage, and
blade servers. To ensure prompt product migration, non-transparency features are implemented in the
same manner as Conventional PCI applications.
Non-transparent bridges allow systems to isolate memory domains by presenting the processor
subsystem as an endpoint, rather than another memory system:
• Base Address registers (BARs) are used to translate addresses
• Doorbell registers are used to transmit interrupts between the address domains
• Scratchpad registers are accessible from both address domains, to allow inter-processor
communication
2.1.3
Two Virtual Channels (VCs)
The PEX 8532 switch supports two full-featured Virtual Channels (VCs) and eight Traffic Classes
(TCs). Traffic-class mapping to port-specific Virtual Channels allows different mappings on different
ports. In addition, this device offers user-selectable Virtual Channel arbitration algorithms to enable
fine-tuning of Quality of Service (QoS), required for specific applications.
The PEX 8532 switch supports Hardware-fixed and Weighted Round-Robin arbitration schemes for
two VCs. This allows QoS fine-tuning, optimum buffer use, and efficient use of system bandwidth.
ExpressLane PEX 8532AA/BA/BB/BC 8-Port/32-Lane Versatile PCI Express Switch Data Book
Copyright © 2007 by PLX Technology, Inc. All Rights Reserved – Version 1.6
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