The Flexible PIC Concentrators (FPCs) provide the infrastructure to power and control PICs and to translate packets to and from each PIC into a standard interface that the FEB processes.

Each Packet Forwarding Engine receives incoming packets from the PICs installed on the FPC and forwards them through the switch planes to the appropriate destination FPC and port. Each FPC contains data memory, which is managed by the Queuing and Memory Interface ASICs, and either one or two Packet Forwarding Engines.

Each FPC contains a translator, a crossbar connection to the FEBs, power subsystem, and the physical PIC connectors. The assembly contains a translation component that converts between the midplane signals and the signals required by the types of supported PICs. The translator fully terminates the PIC side connection, providing local flow control, buffering, and electrical conversion.

The FPCs interface with the following router system components: the PEMs, CBs, FEBs, and PICs.

The FPC slots on the router allow four PICs in Type 1 or Type 2 FPCs and one PIC in a Type 3 FPC to share power circuits and a CPU. Up to four FPCs install vertically in the front of the router (see Figure 1). The FPC slots are numbered left to right from FPC2 to FPC5. Depending on the FPC type, an FPC has either one or four slots into which a PIC can be installed. An FPC can be installed into any FPC slot on the router, regardless of which PICs it contains.

If a slot is not occupied by an FPC, an FPC blank panel must be installed to shield the empty slot and to allow cooling air to circulate properly through the router.

FPCs are hot-removable and hot-insertable, as described in M120 Field-Replaceable Units (FRUs). 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 on other FPC slots continues uninterrupted during this process.

Figure 1: FPC and CFPCs Installed in an M120 Router Chassis

Faceplates on FPCs for the M120 router are labeled with the FPC type (FPC1, FPC2, or FPC3). The faceplates on the CFPCs are labeled with their CFPC type, Ethernet 10GBASE XFP or OC192.

Figure 2 shows the three types of FPCs that the M120 router supports.

Figure 2: FPC1, FPC2, and FPC3 for the M120 Router

• FPC Components
• FPC Terminology