x4

x4

CPU

CPU

CPU

CPU

PEX 8617

x4

Memory

x16

x16

x4

Chipset

Endpoint

PCIe Gen1 or PCIe Gen2 slots

Endpoint

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.

10 GE

10 GE

MAC/PHY

MAC/PHY

x8

x4

x4

Dual-Port NIC

PEX 8617

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.

x8

x4

x4

Quad-Port FC HBA

PEX 8617

FC

FC

FC Cont.

FC

FC

FC Cont.

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.

x4

CPU

CPU

CPU

CPU

Memory

Chipset

CPU

CPU

CPU

CPU

x4

PEX 8617

NT

Memory

Chipset

8 Disk Chassis

PEX 8617

8 Disk Chassis

FC

Control

FC

Control

FC

Control

FC

Control

NT

PEX 8617

NT

x4

x4

x4

x4

x4

x4

x4

x4

x4

Backup

System

PEX

8617

Figure 6. Dual Cast in Storage Systems