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M120 Flexible PIC Concentrators (FPCs) Description


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
FPC and CFPCs Installed in an M120 Router

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
and FPC3 for the M120 Router

FPC Components

Each FPC consists of the following components:

  • FPC card carrier, which includes the PIC slots.

  • HSL2 conversion FPGA, a bridge between the HSL2 interface and the interface required by the types of supported PICs (either BD8, BD32 or HSL1).

  • HSL2 crossbar connection to the FEBs.

  • PIC CPU complex.

  • Physical PIC connectors.

  • Midplane connectors and power circuitry.

  • Processor subsystem, which includes a 667-MHz CPU, system controller, 128 MB of SDRAM, and two Fast Ethernet links to the Control Board.

  • An LED, located on the craft interface above the FPC, that displays the status of the FPC.

  • FPC online/offline button, located on the craft interface above the FPC.

FPC Terminology

Regardless of whether you are holding an FPC vertically or horizontally, the documentation uses the same terms for all four edges of the FPC

  • Faceplate—Edge of the FPC that has slots into which you insert the PICs

  • Connector edge—Edge opposite the faceplate; this edge has the connectors that attach to the midplane

  • Top edge—Edge at the top of the FPC when it is vertical

  • Bottom edge—Edge at the bottom of the FPC when it is vertical