CPU
CPU
CPU
CPU
FC
FC Cont.
Quad-Port FC HBA
x4
FC
Chipset
Endpoint
Memory
FC
FC Cont.
x4
PEX 8617
x8
x16
x16
x4
FC
PEX 8617
Endpoint
Figure 5. Quad-Port Fibre-Channel HBA
Failover Storage Systems
The PEX 8617’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 8617 to
copy data going to its two downstream ports to the
backup system and vice versa (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. Non-Transparent (NT) ports
are used to isolate the host domains of the backup
system from the primary system.
CPU
CPU
CPU
CPU
CPU
CPU
CPU
CPU
x4
x4
x4
PCIe Gen1 or PCIe Gen2 slots
Figure 3. Fan-in/out Usage
Network Interface Cards
The PEX 8617 can also be utilized in communications
applications such as Network Interface Cards (NICs).
NICs, like the one shown in Figure 4, can utilize the
PEX 8617 for its fan-out capabilities. In the example
below, the PEX 8617 is being used on a Dual-port 10-
Gigabit Ethernet (GE) NIC card. The PEX 8617 utilizes
a x8 link to connect to the host and two x4 downstream
links to fan-out to the 10GE ports. The peer-to-peer
communication feature of the PEX 8617 allows the
endpoints to communicate with each other without any
intervention or management by the host.
Dual-Port NIC
Backup
System
Chipset
Memory
Chipset
x4
Memory
10 GE
MAC/PHY
x4
x4
x4
NT
PEX 8617
PEX
8617
x4
10 GE
MAC/PHY
x4
PEX 8617
x8
x4
x4
x4
NT
NT
PEX 8617
x4
x4
FC
Control
PEX 8617
x4
FC
Control
x4
FC
Control
Figure 4. 10GE NIC Fan-Out
Host Bus Adapters
The PEX 8617 is well suited for Host Bus Adapter cards
(HBAs) as well. Figure 5 shows a Quad-Port Fibre
Channel HBAs utilizing the PEX 8617 to allow
connectivity to two Fibre Channel (FC) controllers. The
PEX 8617 uses a x8 link on the upstream port and two
x4 downstream links to fan-out to the FC Controllers
Each FC controller supports two FC ports.
FC
Control
8 Disk Chassis
8 Disk Chassis
Figure 6. Dual Cast in Storage Systems
PLX [ PLX TECHNOLOGY ]
