Juniper Networks M5 - Manual (Page 29)

Packet Forwarding Engine
•
Power distribution—The midplane distributes power to all router components from the
power supplies attached to it.
•
Signal connectivity—The midplane transports the signals exchanged by system
components for monitoring and control purposes.
Figure 4: Midplane
1304
Midplane
Physical Interface Cards (PICs)
Physical Interface Cards (PICs) physically connect the router to network media. They are
housed in Flexible PIC Concentrators (FPCs); for more information about FPCs, see “Flexible
PIC Concentrators (FPCs)” on page 10.
PICs receive incoming packets from the network and transmit outgoing packets to the
network, performing framing and line-speed signaling for their media type as required.
PICs also encapsulate outgoing packets received from the FPCs before transmitting them.
The controller ASIC on each PIC performs additional control functions specific to the PIC
media type.
The router supports various PICs, including ATM, Channelized, Gigabit Ethernet, IP Services,
and SONET/SDH interfaces. For complete PIC specifications, see the M5 and M10 Internet
Routers PIC Guide.
Some PICs, such as selected Gigabit Ethernet PICs, accept small form factor pluggables (SFPs),
which are fiber-optic transceivers that can be removed from the PIC. Various SFPs have
different reach characteristics. You can mix them in a single PIC and change the combination
dynamically. SFPs are hot-removable and hot-insertable, as described in “Field-Replaceable
Units (FRUs)” on page 3. For SFP replacement instructions, see “Replace an SFP” on page
95. For information about PICs that use SFPs, see the M5 and M10 Internet Routers PIC Guide.
Up to four regular PICs install into an M5 router and up to eight regular PICs install into an
M10 router, as shown in Figure 1 and Figure 2. The PIC slots on an M5 router and in the upper
FPC on an M10 router are numbered from 0/0 (zero/zero) through 0/3, right to left. The PIC
slots in the lower FPC on an M10 router are numbered from 1/0 (one/zero) through 1/3, right
to left. The slot number for a PIC appears next to its offline button on the craft interface (see
“PIC Offline Buttons” on page 16). The number of ports on a PIC depends on the type of PIC.
Hardware Component Overview 9