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Clear Channel 6-Port T3 (DS3) Line Card Installation and Configuration
OL-3449-02
Chapter4 Configuring the 6T3 Line Card CLI-Controlled OIR

Bit Error Rate Testing

The ratio of received bits on an interface that co ntain errors is called the bit error rate (BE R). A bit error
rate test (BERT) is used to check the BER. T3 bit error rate testing is used on the Cisco 7304 router to
check communication between local and remote DS3 ports. If traffic is not being transm itted or recei v ed
on a DS3 port, or if the quality of the line simply needs to be tested, T3 b it er ror ra te testin g ca n be u sed
to test the port.
For information on performing bit error rate testing, refer to T3 Bit Error Rate T e sting on the Cisco 7 304
Router.
CLI-Controlled OIR
Line cards can be removed from the Cisco 7304 router w ith out disrup tin g d ata f low by using t he
hw-module slot slot # stop/start command in EXEC mode. The hw-module slot slot # stop command
will stop traffic, shut down all line card in terfa ces, and de acti v ate the line card. T he hw-module slot slot
# start command resets the line card, puts the line card back online and turns off the OIR LED.
Note Upon insertion of a line card, the system will automatically activate the card. The hw-module slot slot
# start command is only necessary when reactivating an installed line card that has been deactivated
with the hw-module slot slot # stop command.
To remove and install an active line card in slot 2 proceed as follows:
Router# hw-module slot 2 stop
When the OIR LED turns green, the line card in slot 2 has been deactivated and can be physically
removed and replaced with a new line card (see the “Line Card Removal and Installation” section on
page 3-3.)
When the new line card is inserted in slot 2 it is automatically reset, put online, and the OIR LED is
turned off.
Line Card Crash Recovery
The 6T3 line card automatically recovers from the following catastrophic errors:
•Fatal serial link errors
•Line card local processor firmware crash
•Loss of keepalive packets from line card local processor
•Hardware errors reported by line card devices
•Too many line card error interrupts (more than 60 interrupts within 10 processor ticks)
If the 6T3 line card encounters more than five fatal errors within one hour, reco very will not be attempted
and the line card will be deactivated. To reactivate the line card use the hw-module slot slot # start
command, or physically remove and replace the lin e card .
The 6T3 line card crash history may be viewed by using the show diag slot command. The cra sh history
is saved as long as the line card is physically present in the chassis. Physically removing the
6T3 line card from the chassis or performing a CLI-controlled OIR will clear the crash history.