Alcatel-Lucent 9500 MXC, User Manual, Page: 645 / 916

9500 MXC User Manual
3DB 23063 ADAA - Rev 004 July 2007 Vol. V-1-7
Test Measurement
The procedures described are designed to confirm correct switch operation; they
are not intended to provide verification of switching times to millisecond
accuracy.
• The procedures provide confirmation of switch action using errored-second
time resolution.
• Confirmation of switching times with millisecond accuracy is a FAT (factory
acceptance test) procedure. Contact Alcatel-Lucent or your supplier for details.
The check procedures described refer to G.821 BER and G.826 link performance
error measurement:
• The BER test can be established using the built-in BER test capability (on
DACs), or an external hand-held tester.
• The built-in BER test and most hand-held BER testers only provide direct
measurement of errored period with a resolution to one second, as an
errored-second count, which depending on where the second starts and stops
in relation to the interruption may result in a count of 1 or a count of 2 for a
service interruption of less than one second. However, an
estimate of the hit
period can be calculated from the Bit Error count (increment of the number
of errored bits), using the circuit data rate. For example, a bit count of 50,000
indicates an outage of 24 ms on an E1 trib (E1 = 2,048,000 bits per second).
• The G.826 link performance test data is provided in the Performance screen.
• G.826 data provides measurement of errored period with a resolution to one
second, as an errored-second count, which depending on where the second
starts and stops in relation to the interruption may result in a count of 1 or a
count of 2 for an interruption of less than one second.
• The procedures involve disconnection of the ODU cable or withdrawal of a
plug-in card, which depending on the way it is done can have a significant
bearing on the observed service restoration time; a soft/slow/imprecise
disconnection will result in variable switch action and switch times. It is for this
reason that the procedures described herein are not appropriate for verifying
9500 MXC protection switch times.
The tests for protection switching provided in this section refer to use of the
built-in G.826 link performance data, or to G.821 BER test capabilities. The
built-in BER test function is used for all BER tests except for DAC testing, when
an external tester is used.