M120 Forwarding Engine Boards (FEBs) Description

The M120 router provides redundant Forwarding Engine Boards (FEBs). The FPC (the board that hosts the PICs) is separate from the FEB (the board that handles the packets). FEBs provide route lookup and forwarding functions from FPCs and CFPCs. FPCs and CFPCs are located on the front of the chassis, and provide power and management to the PICs through the midplane. The midplane relays signals to the FEB (inserted from the rear of the chassis, which processes the packets.

The midplane architecture allows any FEB to carry traffic for any FPC. You can configure the mapping of FPCs to FEBs. If a FEB fails, a backup FEB can quickly take over packet forwarding.

Figure 1: M120 FEB

FEB Components

Each FEB consists of the following components:

• I-chip ASIC, which provides multiple paths for PFE to PIC communication.
• H2S—Bridge between HSLA and one SPI4 interface.
• A crossbar switch that provides connection between the FEB WAN links and the FPC WAN links.
• Three LEDs located on the FEB faceplate that display the status of the FEB.

  M120 Forwarding Engine Boards (FEBs) LEDs describes the functions of the FEB LEDs.

• Six LEDs located on the FEB faceplate indicate which FPC the FEB is connected to, labeled 0 through 5. The illuminated green LED corresponds to the FPC connected to the FEB.
• Midplane connectors and power circuitry.
• Maximum 20-Gbps fabric interface.
• Online/offline button.