Packet Forwarding Engine
M40 Internet Router Hardware Guide
14
19.44-MHz stratum 3 reference clock—Generates clock signal for SONET/SDH PICs.
I
2
C controller—Monitors the status of router components.
Debug port—Connects the SCB to a laptop or other monitoring device through an
RS-232 (EIA-232) serial cable. It uses a DB-25 connector.
Four LEDs—Indicate SCB status. There are two green ones labeled
ACTIVE
and
RUN
, and
two amber ones labeled
STAT1
and
STAT2
. Table 4 describes the LED states.
Reset switch—Restarts the SCB when pressed, causing the Packet Forwarding Engine to
reset and halting packet forwarding for up to approximately two minutes. Do not use the
reset switch under normal circumstances; to access it, push the end of a paper clip or
other small probing device through the hole in the SCB faceplate.
Extractor clips—Control the locking system that secures the SCB in the chassis.
Figure 5: System Control Board
For specific information about SCB components (for
example, the amount of SSRAM and DRAM), issue the
show chassis scb
command.
LEDs
1005
Access to
reset switch
Debug port
