Description of the problem

For troubleshooting purposes, a site wants to view the Optix Metro3000 's AL1 single board port traffic in the ATM performance real-time monitoring interface, but it is not clear how to do the calculation. The screenshot of the corresponding interface is shown below.

Processing

None

root cause

none

Solution

1, the bandwidth and the number of signaling elements conversion relationship is as follows: STM-1 service frame is 270 * 9 bytes, but when carrying ATM services, ATM services are only mapped to the C4, not mapped to the VC4. In this way, STM-1 equivalent ATM signaling elements for 260 × 9 × 8 × 8000/8/53 = 353207. If binding 10M, can also be roughly calculated in this way, 155M corresponds to 353207 signaling elements, then 10M corresponds to 10M * 353207/155 = 22787 signaling elements.

2, AL1 single board can be external port as well as VCTRUNK port statistics, the above report is the external port. The value of each cycle is a statistical value. The method of calculating the traffic is as follows. (number of signaling elements received by T87 - number of signaling elements received by T78)/9 (cycle)*5 (S) = (573238-516966)/9*5 = 1250 signaling elements/second, 1250*155/353207 = 0.55Mbit/s.

3. The total number of signaling elements received by the AL1 external port is calculated as follows.

(Total number of signaling elements received by T87 + Total number of idle signaling elements received by T87 - Total number of signaling elements received by T78 - Total number of idle signaling elements received by T78)/9 (cycles)*5 (S) = (153420320+573238-137961116-516966)/9*5 = 344788 signaling elements, taking into account the factors such as the port statistical error, the value is also similar to 353207 letter elements.

Suggestion and Summary

This case aims to illustrate the following two points:

1. the interface ATM performance value is a statistical value;

2. how to calculate port traffic by viewing ATM performance data.

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