M160 Internet Router Hardware Guide
an entire FPC slot in the chassisand insert directly into the slot rather than
into an FPC card carrier.)
Flexible PIC Concentrator(FPC)—Processes incoming and outgoing packets.
Up to eight FPCs plug into the midplane from the front of the chas sis. Each
FPC accommodates up to four PICs.
Packet ForwardingEngine Clock Generator (PCG)—Sends clock signals to
the other PacketForwarding Engine components. Two PCGs plug into the
midplane from the rear of the chassis.
Switching and ForwardingModule (SFM)—Performs route lookup, filtering,and
switching. Up to four SFMs plug into the midplane from the rear of the chassis.
For informationabout Packet Forwarding Engine components, see the following
sections:
Midplane on page 12
Physical Interface Cards(PICs) on page 13
Flexible PIC Concentrators(FPCs) on page 14
PacketForwarding Engine Clock Generators (PCGs) on page 18
Switching and ForwardingModule (SFM) on page 19
Midplane
The midplane is a panel locatedin the center of the chassis, running from side
to side and forming the rear of the FPC cardcage (see Figure 4). All router
components other than PICs plug directly into the midplane. The midplan e contains
an EEPROM that stores the serial number and revisionlevel of the midplane.
Themidplaneperformsthefollowingfunctions:
Transferof packets—The midplane accepts an incoming packet after it is
processedbyanFPC,andtransmitsittoanSFM.TheSFMperformsswitching
and forwarding functions and transfers outgoing packets back ac ross the
midplane to the FPCs for transmission to the network.
Power distribution—The midplane distributes power to all rout er components
from the power supplies attached to it.
Signal connectivity—The midplanetransports the signals exchanged by
system components for monitoringand control purposes.
12 Packet Forwarding Engine