PEX 8648 utilizes its NT port to isolate the hosts on the
switch fabrics and the remaining 10 downstream ports
on each switch are used to fan-out to the 20 AMC blades
(or 10 AMC Carrier Modules).
CPU
CPU
CPU
CPU
Memory
Chipset
10-20 AMC or 10 AMC
Carrier Modules
Fabric
x16
x16
x16
Endpoint
To
Backplane
CPU
PEX 8648
PEX 8648
x8
x8
x8
Endpoint
x4
x4
NT
To other
Fabric
PEX 8648
PCIe Gen1 or PCIe Gen2 slots
Figure 3. Fan-in/out Usage
Figure 5. ATCA/MicroTCA Backplane Usage
Communications Systems
The PEX 8648 can also be utilized in communications
applications. Figure 4 shows a PEX 8648 being used in a
router to connect multiple endpoints in a line card to the
control module using PowerPC. The link-widths for each
module can be configured as required. The peer-to-peer
communication feature of the PEX 8648 allows the
endpoints to communicate with each other without any
intervention or management by the host.
Fail-Over Storage Systems with Dual Cast
The PEX 8648’s Dual Cast feature proves to be very
useful in storage systems. In the example shown in
Figure 6, the Dual Cast feature enables the PEX 8648 to
copy data coming from the host to two downstream ports
(see yellow traffic patterns) in one transaction as
opposed to having to execute two separate transactions
to send data to the redundant chassis. By offloading the
task of backing up data onto the secondary system,
processor and system performance is enhanced. The
PEX 8648’s NT port is used to isolate the backup system
from the primary system.
Control
Memory
PowerPC
Module
Backup
System
CPU
CPU
CPU
CPU
CPU
CPU
CPU
CPU
x8 or x4
End
End
Point
Point
PEX 8648
Memory
x8
Memory
Chipset
Chipset
End
Point
End
Point
x8
x8
NT
End
Point
End
Point
PEX 8648
PEX 8648
Line Card
All
All
x8s
x8s
Figure 4. Router Usage
Backplane Communication
With 48 lanes and 12 ports, the PEX 8648 is well suited
for backplane applications requiring high connectivity (a
large number of ports). Figure 5 represents an ATCA or
MicroTCA backplane application with two switch fabric
blades and multiple AMC blades. In this example, two
PEX 8648s provide peer-to-peer data exchange for up to
20 AMC blades connecting to the switch fabric. The
NT
NT
NT
NT
PEX 8616
PEX 8616
x4 x4
PEX 8616
PEX 8616
x4 x4
x4
x4
x4
x4
FC
FC
FC
FC
FC
FC
FC
FC
8 Disk Chassis
8 Disk Chassis
8 Disk Chassis
8 Disk Chassis
Figure 6. Dual Cast in Storage Systems
Preliminary - PLX Confidential
PLX [ PLX TECHNOLOGY ]
