M10i Compact Forwarding Engine Board (CFEB) and Enhanced Compact Forwarding Engine Board (CFEB-E) Description

The Compact Forwarding Engine Board (CFEB) or Enhanced Compact Forwarding Engine Board (CFEB-E) performs route lookup, filtering, and switching on incoming data packets, then directs outbound packets to the appropriate FPC for transmission to the network. It can process 15 million packets per second (Mpps).

One or two CFEBs or CFEB-Es can be installed into the midplane from the rear of the chassis, as shown in M10i Chassis Description.

Caution: The M10i Internet router does not support a mixture of CFEB and CFEB-E hardware. If you install two devices, they must both be CFEBs or they must both be CFEB-Es.

Only one CFEB or CFEB-E is active at a time; the optional second CFEB or CFEB-E is in standby mode. By default, the CFEB or CFEB-E in slot CFEB 0 is active. To modify the default, include the appropriate cfeb statement at the [edit chassis redundancy] hierarchy level of the configuration, as described in the section about CFEB or CFEB-E redundancy in the Junos OS System Basics Configuration Guide.

Note: For specific information about CFEB or CFEB-E components (for example, the amount of SDRAM), issue the show chassis cfeb command.

CFEBs or CFEB-Es are hot-pluggable when you replace a CFEB with a CFEB or a CFEB-E with a CFEB-E, as described in M10i Field-Replaceable Units (FRUs). To upgrade from a CFEB to a CFEB-E or to downgrade from a CFEB-E to a CFEB requires a system reboot as described in Upgrading or Downgrading an M10i CFEB or CFEB-E.

Removing the standby CFEB or CFEB-E has no effect on router function. If the active CFEB or CFEB-E fails or is removed from the chassis, the effect depends on how many CFEBs or CFEB-Es are installed:

• If there is one CFEB or CFEB-E, forwarding halts until the CFEB or CFEB-E is replaced and functioning again. For a minimum configuration, it takes approximately 2 minutes for the replaced CFEB or CFEB-E to boot and become active; reading in router configuration information can take additional time, depending on the complexity of the configuration.
• If there are two CFEBs or CFEB-Es, forwarding halts while the standby CFEB or CFEB-E boots and becomes active, which takes approximately 1 minute; synchronizing router configuration information can take additional time, depending on the complexity of the configuration.

For CFEB or CFEB-E replacement instructions, see Replacing, Upgrading, or Downgrading an M10i CFEB or CFEB-E.

The CFEB or CFEB-E 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 or CFEB-E to the Routing Engine routing link-state updates and other packets destined for the router that have been received through the router interfaces.

The CFEB or CFEB-E provides the following functions:

• Route lookups—Performs route lookups using the forwarding table stored in the synchronous SRAM (SSRAM) on CFEBs or stored in the RLDRAM on CFEB-Es.
• 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 or CFEB-E, 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 or CFEB-E are sent to the Routing Engine using system log messages.

CFEB

Figure 1: CFEB

The CFEB has the following major components:

• Processing components:
  • 266-MHz CPU and supporting circuitry
  • Integrated ASIC
  • 33-MHz PCI bus
• Storage components:
  • 128-MB SDRAM for packet memory
  • 128-MB SDRAM for the microkernel
  • 8-MB SSRAM for route lookup
  • 4-MB 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
  • I2C/EEPROM containing the serial number and revision level
  • Two 512-KB boot flash EPROMs (programmable on the board)
• One PowerPC 8245 integrated processor
• Three LEDs—A green LED labeled OK, a red LED labeled FAIL, and a blue LED labeled MASTER indicate CFEB status. .
• Online/Offline button—Prepares the CFEB for removal from the router when pressed.
• Ejector levers—Control the locking system that secures the CFEB in the chassis.

CFEB-E

The CFEB-E provides the following enhanced features:

• Increased number of logical interfaces.
• Increased route, nexthop, and interface lookup memory.
• Increased FPC throughput.
• Enhanced class of service features, including:
  • More queues and priority levels
  • Increased drop precedence per queue
  • Excess bandwidth allocation in proportion to weights
  • Hierarchical policing
  • Increased number of WRED profiles
  • Independent EXP and DSCP rewrite
  • Independent Layer 2 and Layer 3 classification on same port

Figure 2: CFEB-E

The CFEB-E has the following major components:

• Processing components:
  • 1-GHz CPU and supporting circuitry
  • Integrated ASIC
  • 33-MHz PCI bus
• Storage components:
  • Three 256-MB SDRAMs for packet memory
  • 1-GB SDRAM for the microkernel
  • Two 64-MB RLDRAMs for route lookup
  • Two 64-MB RLDRAMs for control memory
• System interfaces:
  • 100-Mbps link for internal interface to the Routing Engine
  • 19.44-MHz reference clock—Generates clock signal for SONET/SDH PICs
  • I2C controller to read the I2C/EEPROMs in the PICs and temperature sensors
  • I2C/EEPROM containing the serial number and revision level
  • Two 512-KB boot flash EPROMs (programmable on the board)
• One MPC8545 integrated processor with 1-GB DDR2 SDRAM
• Three LEDs—A green LED labeled OK, a red LED labeled FAIL, and a blue LED labeled MASTER indicate CFEB-E status.
• Offline button—Prepares the CFEB-E for removal from the router when pressed.
• Ejector levers—Control the locking system that secures the CFEB-E in the chassis.