pex-8632 PLX, pex-8632 Datasheet - Page 2

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pex-8632

Manufacturer Part Number
pex-8632
Description
32-lane, 12- Port Pci Express Gen 2 5.0 Gt/s Switch, 27 X 27mm Fcbga
Manufacturer
PLX
Datasheet
Dual-Host & Failover Support
The PEX 8632 product supports a Non-Transparent
(NT) Port, which enables the implementation of multi-
host systems in communications, storage, and blade
server applications. The NT port allows systems to
isolate host memory
domains by presenting
the processor subsystem
as an endpoint rather
than another memory
system. Base address
registers are used to
translate addresses;
doorbell registers are
used to send interrupts
between the
address domains;
and scratchpad
registers
(accessible from both CPUs) allow inter-processor
communication (see Figure 2).
Dual Cast™
The PEX 8632 supports Dual Cast, a feature which
allows for the copying of data (e.g. packets) from one
ingress port to two egress ports allowing for higher
performance in dual-graphics, storage, security, and
redundant applications.
Read Pacing™
The Read Pacing feature allows users to throttle the
amount of read requests being made by downstream
devices. When a downstream device requests several
long reads back-to-back, the Root Complex gets tied up
in serving this downstream port. If this port has a narrow
link and is therefore slow in receiving these read packets
from the Root Complex, then other downstream ports
may become starved – thus, impacting performance. The
Read Pacing feature enhances performances by allowing
for the adequate servicing of all downstream devices.
Hot-Plug for High Availability
Hot-Plug capability allows users to replace hardware
modules and perform maintenance without powering
down the system. The PEX 8632 Hot-Plug capability
feature makes it suitable for High Availability (HA)
applications. Three downstream ports include a
Standard Hot-Plug Controller. If the PEX 8632 is used in
an application where one or more of its downstream
ports connect to PCI Express slots, each port’s Hot-Plug
Controller can be used to manage the hot-plug event of
its associated slot. Every port on the PEX 8632 is
equipped with a hot-plug control/status register to
Point
Point
Point
Point
Point
Point
Point
Point
Figure 2. Non-Transparent Port
Figure 2. Non-Transparent Port
End
End
End
End
End
End
End
End
PEX 8632
PEX 8632
PEX 8632
PEX 8632
Complex
Complex
Complex
Complex
Complex
Complex
Primary Host
Primary Host
Primary Host
Primary Host
Primary Host
Primary Host
Point
Point
Point
Point
Point
Point
Point
Point
Root
Root
Root
Root
Root
Root
CPU
CPU
CPU
CPU
CPU
CPU
End
End
End
End
End
End
End
End
NT
NT
Point
Point
Point
Point
Point
Point
Point
Point
End
End
End
End
End
End
End
End
Secondary Host
Secondary Host
Secondary Host
Secondary Host
Secondary Host
Secondary Host
Non-Transparent
Non-Transparent
CPU
CPU
CPU
CPU
CPU
CPU
Port
Port
support hot-plug capability through external logic via the
I
SerDes Power and Signal Management
The PEX 8632 supports software control of the SerDes
outputs to allow optimization of power and signal
strength in a system. The PLX SerDes implementation
supports four levels of power – off, low, typical, and
high. The SerDes block also supports loop-back modes
and advanced reporting of error conditions, which
enables efficient management of the entire system.
Interoperability
The PEX 8632 is designed to be fully compliant with the
PCI Express Base Specification r2.0, and is backwards
compatible to PCI Express Base Specification r1.1 and
r1.0a. Additionally, it supports auto-negotiation, lane
reversal, and polarity reversal. Furthermore, the
PEX 8632 is designed for Microsoft Vista compliance.
All PLX switches undergo thorough interoperability
testing in PLX’s Interoperability Lab and compliance
testing at the PCI-SIG plug-fest.
Applications & Usage Models
Suitable for host-centric as well as peer-to-peer traffic
patterns, the PEX 8632 can be configured for a broad
range of form factors and applications.
Host Centric Fan-out
The PEX 8632, with its symmetric or asymmetric lane
configuration capability, allows user-specific tuning to a
variety of host-centric applications. Figure 3 shows a
typical server-based design where the root complex
provides a PCI Express link that needs to be expanded to
a larger number of smaller ports for a variety of I/O
functions. In this example, the PEX 8632 has an 8-lane
upstream port, and four downstream ports using a
combination of x4 and x8 links.
Backwards Compatibility with PCIe Gen 1
2
C interface.
Endpoint
Endpoint
Endpoint
Endpoint
Endpoint
Endpoint
Endpoint
Endpoint
Figure 3. Fan-in/out Usage
x4
x8
Chipset
Chipset
Chipset
Chipset
CPU
CPU
CPU
CPU
x8
x8
PEX 8632
PEX 8632
PEX 8632
PEX 8632
CPU
CPU
CPU
CPU
x8
x4
x4
Memory
Memory
Memory
Memory

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