Juniper Networks M10i manual Cfeb Components

M10i Internet Router Hardware Guide

For CFEB replacement instructions, see “Replacing a CFEB” on page 90.

The CFEB communicates with the Routing Engine using a dedicated 100-Mbps Fast Ethernet link that transfers routing table data from the Routing Engine to the forwarding table in the integrated ASIC. The link is also used to transfer from the CFEB to the Routing Engine routing link-state updates and other packets destined for the router that have been received through the router interfaces.

The ASICs and other components on the CFEB provide the following functions:

■Route lookups—Performs route lookups using the forwarding table stored in the synchronous SRAM (SSRAM).

■Management of shared memory —Uniformly allocates incoming data packets throughout the router's shared memory.

■Transfer of outgoing data packets—Passes data packets to the destination FIC or PIC when the data is ready to be transmitted.

■Transfer of exception and control packets—Passes exception packets to the microprocessor on the CFEB, which processes almost all of them. The remainder are sent to the Routing Engine for further processing. Any errors originating in the Packet Forwarding Engine and detected by the CFEB are sent to the Routing Engine using system log messages.

CFEB Components

The CFEB has the following major components:

■Processing components:

■266-MHz CPU and supporting circuitry

■Integrated ASIC

■33-MHz PCI bus

■Storage components:

■SDRAM for packet memory

■SDRAM for the microkernel

■SSRAM for route lookup

■SSRAM for control memory

■System interfaces:

■100-Mbps Ethernet link for internal interface to the Routing Engine

■19.44-MHz reference clock that generates clock signal for SONET/SDH PICs

■I2C controller to read the I2C/EEPROMs in the PICs and temperature sensors

12■ Compact Forwarding Engine Board (CFEB)