M40e Flexible PIC Concentrators (FPCs) Description
Flexible PIC Concentrators (FPCs) house the PICs that connect the router to network media (for information about PICs, see M40e PICs Description). 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 M40e Packet Forwarding Engine Architecture.
FPCs are hot-removable and hot-insertable, as described in M40e 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, 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 Replacing an FPC in an M40e Router.
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 either one or up to four PICs, depending on the type of FPC and PIC. 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 1, 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 1: Front of M40e Chassis with Four-PIC FPC Installed in Slot FPC0
