Delta Electronics Sonet OC-48/SDH User Manual download pdf (Page 38)

Interface Diagnostic Commands

t3-options {

bert-algorithm all-ones-repeating;

bert-error-rate 0;

bert-period 120;

}

The run duration lasts from 1 to 240 seconds, with Cabernet running for 120 seconds. The

error rate value is an integer between 0 and 7. The supplied value becomes an exponential and

results in a final error rate between 10

-0

(no errors) and 10

-7

(1 error in 10 million received bits).

The bit patterns to test are too numerous to mention here in detail. Cabernet has opted to send a

pattern where every bit is set to a value of 1. Some of the more common testing patterns include:

all-ones-repeating The transmitted pattern is 1111111111111111…

all-zeros-repeating The transmitted pattern is 0000000000000000…

alternating-ones-zeros The transmitted pattern is 1010101010101010…

alternating-double-ones-zeros The transmitted pattern is 1100110011001100…

Starting and Stopping the Test

Once the BERT parameters are committed, you begin the test with the following command:

user@host> test interface t3-1/2/0 t3-bert-start

The test runs for the specified second duration as configured. Should you wish to terminate

the test sooner, use the following command:

user@host> test interface t3-1/2/0 t3-bert-stop

BERT Test Results

You can view the results of the BERT test with the show interfaces extensive command.

To immediately locate the BERT values in the output, use the JUNOS software pipe function-

ality. The find string option starts the output at the specified string:

user@Cabernet> show interfaces t3-1/2/0 extensive | find BERT

BERT time period: 120 seconds, Elapsed: 120 seconds (completed)

Algorithm: All ones, Repetitive (22), Error rate: 10e-0

Bit count : 0, Overflows: 0

Error bit count: 0, Overflows: 0

LOS status: OK, LOS count: 1, LOS seconds: 239

. . .

In our example, it appears that the transmission lines are noise free between Cabernet and

the looping device. The BERT test ran for all 120 seconds using the all-ones pattern. It found

zero errors using the 10e-0 error rate.

1 2 ... 33 34 35 36 37 38 39 40 41 42 43 ... 46 47

No comments

Delta Electronics Sonet OC-48/SDH User Manual Page 38