The ExpressLane PEX 8525 device offers PCI Express switching capability 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 8525 is well suited for fan-out, aggregation, dualgraphics, peer-to-peer, and intelligent I/O module applications.
The PEX 8525 offers highly configurable ports. There are a maximum of 5 ports that can be configured to any legal width from x1 to x16, in any combination to support your specific bandwidth needs. The ports can be configured for symmetric (each port having the same lane width and traffic load) or asymmetric (ports having different lane widths) traffic. In the event of asymmetric traffic, the PEX 8525 features a flexible central packet memory that allocates a memory buffer for each port as required by the application or endpoint. This buffer allocation along with the device's flexible packet flow control minimizes bottlenecks when the upstream and aggregated downstream bandwidths do not match (are asymmetric). Any of the ports can be designated as the upstream port, which can be changed dynamically.
The PEX 8525 architecture supports packet cut-thru with a max latency of 115ns (x8 to x8). This, combined with large packet memory (1024 byte maximum payload size) and non-blocking internal switch architecture, provide full line rate on all ports for performance-hungry applications such as storage servers or storage switch fabrics.
The PEX 8525 provides end-to-end CRC protection (ECRC) and Poison bit support to enable designs that require end-to-end data integrity. These features are optional in the PCI Express specification, but PLX provides them across its entire ExpressLane switch product line.
The PEX 8525 provides several ways to configure its operations. The device can be configured through strapping pins, I2C interface, CPU configuration cycles, or an optional serial EEPROM. This allows for easy debug during the development phase, performance monitoring during the operation phase, and driver or software upgrade.
The PEX 8525 is designed to be fully compliant with the PCI-SIG revision 1.1 specification. Additionally, it supports auto-negotiation, lane reversal, and polarity reversal. The PEX 8525 also undergoes thorough Interoperability testing in PLX’s Interoperability Lab.
