February, 2007
PCI Express Station Functional Description
4.3
PCI Express Station Functional Description
The PEX 8532 groups 16 SerDes together into each station. A station can have one to four ports, as
defined in Table 4-1. The station forwards ingress packets to the internal fabric, to be routed to the
egress station.
Each station implements the PCI Express Physical (PHY) Layer and Data Link Layer (DLL) functions
for each of its ports, and aggregates traffic from these ports on to a transaction-based, non-blocking
internal fabric. The PCI Express station also performs many Transaction Layer functions, while the
packet queuing and ordering aspects of this layer are handled by the Crossbar Switch Control blocks.
During system initialization, software initiates Configuration requests that set up the PCI Express
interfaces, Device Numbers, and Address maps across the various ports. These maps are used to direct
traffic between ports during standard system operation. A PCI Express station can contain multiple ports
(one upstream and multiple downstream). Traffic flow between different ports of the same station, or
ports on different stations, is supported by the central internal fabric.
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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