M40E Packet Forwarding Engine Clock Generators (Pcgs) Description - Juniper M40E Hardware Manual

M40e Multiservice Edge Router Hardware Guide
Table 3: FPCs Supported by the M40e Router (continued)
FPC Type FPC Name
2 Enhanced Plus FPC2
Related
Documentation

M40e Packet Forwarding Engine Clock Generators (PCGs) Description

18
All manuals and user guides at all-guides.com
FPC Model Number
M40e-FPC2-EP
Holding an M40e FPC Overview on page 133
Installing an FPC in an M40e Router on page 193
Troubleshooting FPCs on the M40e Router on page 152
The M40e Multiservice Edge Router has two Packet Forwarding Engine Clock Generators
(PCGs) installed in the slots at the rear of the chassis that are labeled
as shown in "M40e Chassis Description" on page 8. The PCGs generate a 125-MHz clock
signal used to gate packet processing. During startup, the active Routing Engine
determines which PCG is master and which is backup, and the MCS relays the decision
to the PCGs and to the modules and ASICs in the Packet Forwarding Engine that use the
clock signal. The modules and ASICs then use only the signal from the master source.
PCGs are hot-pluggable, as described in "M40e Field-Replaceable Units (FRUs)" on
page 157. Removal or failure of the backup PCG does not affect router function. When
the master PCG fails or is removed from the chassis, however, the Packet Forwarding
Engine resets so that the components start using the signal from the other PCG (which
becomes the master). The Packet Forwarding Engine cannot accept incoming packets
until each PFE component, including the SFM and FPCs, resets to recognize the new
master PCG. This can result in traffic halting for several minutes.
For PCG replacement instructions, see "Replacing a PCG in an M40e Router" on page 196.
Each PCG (shown in Figure 8 on page 19) has the components:
Signal generator—Provides a 125-MHz system clock signal.
EEPROM—Stores the serial number and revision level of the PCG.
Three LEDs—Indicate PCG status. There is a blue one labeled
labeled , and an yellow one labeled
OK
the LED states.
Offline button—Prepares the PCG for removal from the router when pressed.
Maximum
Maximum
Throughput
Number of
per FPC (full
PICs
duplex)
Supported
1 3.2 Gbps
MASTER
. "M40e PCG LEDs" on page 19 describes
FAIL
Copyright © 2010, Juniper Networks, Inc.
First Junos OS
Release
7.3
PCG 0 and PCG 1 ,
, a green one