Application Note: Using JDSU's Xgig BERT for DWDM

Application Note
Using the JDSU Xgig ® Bert for DWDM
The following describes how to use the BERT to provide standard test configuration for DWDM installation.
For this situation, two XGIG BERTs will be needed so the user can send and compare data simultaneously.
Connecting the Xgig-BERT
HEAD TO HEAD TEST: This will simultaneously test both directions of data flow in the system under test.
Connect the Tx and Rx terminals on one of the BERTs to a Fibre Channel or Gigabit Ethernet port on the
System Under Test. Connect the Rx and Tx terminals on the other BERT to a port of the same type on the
System Under Test. Run tests as shown in figure 1 below:
Figure 1
XGIG-BERT
In Send and
Compare
mode
System
Under
Test
XGIG-BERT
In Send and
Compare
mode
Selecting the BERT Configuration
1. Start the BERT application by clicking on the XGIG Maestro icon.
2. Lock at least one BERT port on the Xgig Chassis. Refer to the User’s Guide for details.
3. Select a configuration file from the file tree. Drag and drop it onto the BERT port. Options include:
GE 32 bit Noise.PTC
GE CJTPAT.PTC
GE CRPAT.PTC
GE CSPAT.PTC
The Maxframe pattern should be used with a single BERT in loopback configuration (see Figure 4).
The folder labeled “GE test in one direction” contains special configurations for testing one direction at a
time (see Figure 6).
4. Select the Link Speed by right clicking on the BERT port and selecting from the menu.
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Application Note: Using the JDSU Xgig® Bert for DWDM
2
Running the Bit Error Rate Test
1. Click the Start Button to begin
the test. To reset and start the
BER measurement again, simply
click the Stop Button and
then the Start Button.
2. The status display shows
the status of the send and
receive state machines as
well as a number of other
metrics.
3. The Bit Error Rate shows
the number of incorrect bits
compared divided by the total
number of bits compared
since last reset.
4. The Bits Mismatched number
gives the count of bit
errors detected by the BERT.
Figure 2

Application Note: Using the JDSU Xgig® Bert for DWDM
3
Error Insertion
In order to verify that the Head to
Head BERT test is connected correctly,
this Bit Err button allows
you to insert bit errors one at a
time at one of the BERTs.
By checking the bit errors detected
at the other BERT, you can verify
your test configuration.
An Example with Errors
Detected by the BERT
1. The Bit Error Rate is greater
than the 10^-12 order of
magnitude expected for a
clean Fibre Channel link after
68 seconds.
2. The Bits Mismatched number
shows the number of bits that
did not match the expected
pattern.
Figure 3

Application Note: Using the JDSU Xgig® Bert for DWDM
4
Additional Configurations for Testing with the XGIG-BERT
1. LOOPBACK TEST: Connect both the transmit (Tx) and receive (Rx) terminals on the BERT to a
Fibre Channel or Gigabit Ethernet port on the System Under Test. Then loop the data path back to the
BERT. The loop back can be internal or external to the System Under Test.
2. LATENCY TEST: Using the same configuration as the loopback tests, this will allow you to measure
the time delay through the system under test and back.
XGIG-BERT
System
Under
Test
Figure 4
Right-click on the port column
and select the desired mode of
operation. Ports set to Latency
mode appear on the Latency measurement
tab.
Select the Latency tab to run the
Latency test.
The Latency test function sends
a data pattern repeatedly and
measures the delay between
transmitting and receiving each
instance of the data pattern.
The display shows the results in
terms of Instantaneous, Average,
Maximum and Minimum delay.
The Latency Data Points metric
shows the number of repetitions
of the test.
Figure 5

Application Note: Using the JDSU Xgig® Bert for DWDM
5
3. TEST ONE DIRECTION AT A TIME: You can also run an end to end test in one direction at a time.
This requires loading a send configuration in one BERT and a compare configuration in the other. Just
load the configurations found a “Test In One Direction” folder.
XGIG-BERT
In Send Only
mode
System
Under
Test
XGIG-BERT
In Compare Only
Mode
XGIG-BERT
In Compare Only
mode
Figure 6
System
Under
Test
XGIG-BERT
In Send Only
Mode
Logging Options
1. Right click on a port column and select the Log submenu to access Options for the Log that is created
each time the BERT is stopped.
2. Chose a file name template and destination folder.
3. Enter values for how often to add a log entry during operation and how many log entries to make.
Figure 7

Application Note: Using the JDSU Xgig® Bert for DWDM
6
Display Options
1. Right click in the port column and select LEDs to open a new window that just contains the LEDs
in a larger format.
2. Right click on the port column and select the text size submenu to choose a text size for the Parameter
table.
3. Right click on the port column and select Parameters to open a dialog box that allows you to
choose what rows appear for all BERT ports in the Parameter table.
Figure 8
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Product specifications and descriptions in this document subject to change without notice. © 2009 JDS Uniphase Corporation 30162817 500 0909 XGIGBERTDWDM.CS.SAN.TM.AE Sept 2009