Adapter Card Aggregation
The number and variety of PCI Express native-mode devices
is growing quickly. As these devices become mainstream, it
will be necessary to create multi-function and multi-port
adapter cards with PCI Express capability.
The PEX 8509 can be used to create an adapter or mezzanine
card that aggregates the PCI Express devices into a single port
that can be plugged into a backplane or a motherboard. Figure
3 shows the PEX 8509 in this application.
Control Planes For Larger Systems
For larger systems that need more than 8 ports, two PEX 8509
devices can be linked together to provide up to 14 ports.
Figure 5 shows such an application. The two PEX 8509
devices together provide connectivity for up to 13 line cards
each via an x1 link. The Control Processor connected to a
PEX 8509 via an x1 port on the controller card in this example
can control up to 13 different line cards.
To Line Cards
7 ports
6 ports
GE
GE
GE
MAC/PHY
MAC/PHY
MAC/PHY
MAC/PHY
GE
1
1
1
1
PEX 8509
4
PEX 8509
PEX 8509
Control
Processor
Memory
Controller Card
Figure 3. Aggregation Adapter Card
Controller Card
Control Plane Application
The PEX 8509 is ideal for migrating existing PCI control
planes in routers to high-speed PCI Express interface to meet
increased packet processing needs. Figure 4 shows a controller
card with a PEX 8509 connecting the Control Processor to as
many as seven line cards each via a x1 port. This usage model
provides connectivity to multiple line cards giving the
processor control over a large number of line cards in mid-
range routers.
Co-Processor-
Security/DSP
NPU/ASIC
Switch
Framer
PHY
Figure 5. Control Plane for Large Systems
Redundant Control Plane Applications
For those systems that need redundant control planes, the
PEX 8509 can be used in conjunction with the PEX 8508
which supports Non-Transparent bridging. With the NT port,
the PEX 8508 can connect to a redundant control card
providing fail-over support. An added benefit of the PEX 8509
& PEX 8508 combination design is the increased fan-out
capability – it is now possible to connect a total of 9 line cards
to the controller card.
Port #1
LC #1
To
Line Cards
PEX 8509
Up to 7 x1
cards
Local
Processor
Line Card 1
Line Card 7
PEX 8508
LC #9
PEX 8509
Port #9
PEX 8509
Control
Processor
Memory
Controller Card
Control
Processor
PEX 8508
NTB
GE Ports
to Fabric
Controller Card
Memory
Control
Processor
Switch
Fabric Card
Switch
Switch
Switch
Figure 4. Control Plane
Controller Card
Memory
Redundant
Control Card
Figure 6. Redundant Control Plane
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