How to Capture a Sequence of OTN Overhead Bytes?

Portable test sets can capture up to 256 bytes from any of the OTN overhead bytes, with programmable triggers, for quick troubleshooting of complex issues.

The byte capture is offered in handheld testers with OTU4 and OTU3 Ethernet over OTN (EoOTN) test modes (e.g., OTU4 with Ethernet and Bulk Payloads). By default, the >OTN Tools >Overhead >Overhead Analysis feature's tab starts in DECODE mode, which allows users to decode certain bytes in real time. For example, by tapping on the TCMi fields, users can decode the received TTI text strings and the BEI/BIAE/BDI/STAT bytes by tapping on the respective fields.


Some test sets may also allow to CAPTURE up to 256 values (consecutive frames) for a selected overhead byte. The capture of received values can get started as soon as users tap on a field (byte), or by looking for specific values with the Pre, Mid and Post trigger functions, for advanced troubleshooting purposes. To enable this functionality, change the BYTE field from DECODING to CAPTURE mode.


Once the capture mode has been enabled, users can select the Trigger Type to program when the acquisition stars, with the following behaviors.

Multi Frame #0 - After tapping on the desired byte, the capture starts at the beginning of the next OTN multi-frame.



Pre Trigger - Starts capturing after the specified Byte Value trigger is detected, including the triggering value (highlighted in yellow).



Mid Trigger - Captures 127 bytes before and after the specified Byte Value trigger is detected, including the triggering value (highlighted in yellow).



Post Trigger - Captures the 255 bytes prior to the specified Byte Value trigger being detected, including the triggering value (highlighted in yellow)



Note: These captured byte sequences are currently for on-screen analysis (troubleshooting) only. They can't be saved or exported.

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