Figure 5: Front of Chassis with Four-PIC FPC Installed in Slot FPC0
Flexible PIC Concentrators (FPCs) house the PICs that connect the router to network media (for information about PICs, see Physical Interface Cards (PICs)). The main function of an FPC is to connect the PICs installed in it to the other router components. An I/O Manager ASIC on the FPC divides each incoming data packet into 64-byte cells and passes the cells through the midplane to the SFM, where another ASIC decides how to distribute them among the memory buffers located on and shared by all installed FPCs. After the SFM decides how to forward a packet, an 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.
Up to eight FPCs install vertically into the midplane from the front of the chassis. The FPC slots are numbered from FPC0 to FPC7, left to right. Each FPC accommodates up to four PICs. 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 5, which shows a chassis with an FPC in slot FPC0, omits the blank FPC panels to show the position of the FPC in the card cage.
Figure 5: Front of Chassis with Four-PIC FPC Installed in Slot FPC0
For information about FPC components and types, see the following sections:
