Flexible PIC Concentrators (FPCs)

Flexible PIC Concentrators (FPCs) house the PICs that connect the router to network media (for information about PICs, see Physical Interface Cards (PICs)). Up to eight FPCs install vertically into the backplane from the front of the chassis. The FPC slots are numbered left to right, from 0 (zero) through 7. Each FPC accommodates up to four PICs and the PIC slots in each FPC are numbered from 0 (zero) through 3, top to bottom.

An FPC can be installed into any FPC slot, regardless of the PICs it contains, and any combination of slots can be used. If a slot is empty, you must install a blank FPC panel to shield it, so that cooling air can circulate properly throughout the card cage. Figure 4, which shows a chassis with an FPC in slot 7, omits the blank FPC panels to show the FPC's position in the card cage.

The main function of an FPC is to connect the PICs installed in it to the other router components. The I/O Manager ASIC on the FPC divides each incoming data packet into 64-byte cells, which the Distributed Buffer Manager ASIC on the backplane distributes among the memory buffers located on and shared by all installed FPCs. After the SCB decides how to forward a packet, the I/O Manager ASIC on the FPC reassembles the corresponding data cells back into network-packet form and passes the packet to the appropriate PIC for transmission to the network. For more information, see Data Flow through the Packet Forwarding Engine.

FPCs are hot-removable and hot-insertable, as described in Field-Replaceable Units (FRUs). When you remove or install an FPC, packet forwarding halts for about 200 ms while the Packet Forwarding Engine adjusts to the change in the amount of memory available in the pool located on and shared by all FPCs. When you install an FPC into a functioning router, press its offline button to activate it and the PICs installed in it. The Routing Engine downloads the FPC software, the FPC runs its diagnostics, and the PICs housed on the FPC are enabled. Forwarding continues uninterrupted during this process. For FPC replacement instructions, see Replace an FPC or Quad-wide PIC.

The PICs that install on both types of FPC are also hot-removable and hot-insertable. For more information, see Physical Interface Cards (PICs).

Figure 4: FPC Installed in Slot FPC7

FPC Components

Each FPC contains the following components:

• FPC card carrier—Houses the other FPC components.
• I/O Manager ASIC—Parses Layer 2 and Layer 3 data and performs encapsulation and segmentation.
• Two identical SDRAM dual inline memory modules (DIMMs)—Form the memory pool shared with the other FPCs installed in the router.
• Parity-protected SSRAM—Stores data structures used by the I/O Manager ASIC.
• Processor subsystem—Manages packet handling in the FPC and communication with the SCB. It is a PowerPC 603e-based CPU with parity-protected DRAM.
• EEPROM—Stores the serial number and revision level of the FPC.
• Two LEDs—Indicate FPC status. There is a green one labeled OK and a red one labeled FAIL. The LEDs for each FPC are located directly below it, on the router craft interface. For more information, see FPC LEDs and Offline Button.
• Offline button—Prepares the FPC for removal from the router when pressed. Like the LEDs, an offline button is located on the craft interface directly below each FPC slot. For more information, see FPC LEDs and Offline Button.
• Extractor clips—Control the locking system that secures the FPC in the card cage.