Understanding 100G OTN Error & Alarm Conditions – LOL

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Loss Of Lane Alignment (LOL) is declared on 100G interfaces when it has not been possible to successfully recover the Logical Lane Marker (LLM) from the logical lanes and then re-assemble the OTU4 frame.

During the lane recovery process the LLM will be present in a lane every 16320 bytes, when the same LLM value has been present for 5 consecutive intervals this LLM value will be accepted and the lane recovery will be considered “In Recovery”.

Loss Of Lane Alignment will be declared in the case where the lane recovery process has failed – either by two or more logical lanes found to contain identical logical lane markers or if there was not a sequence of 5 consecutive LLM values.

Loss Of Lane Alignment is different from LOF Lane in that the interface has been receiving data blocks that have been framed up on, however the LLM has not been successfully recovered in order to re-align the lanes in the correct order. Similarly to LOF Lane the condition can be declared for each logical lane.

2 Responses to "Understanding 100G OTN Error & Alarm Conditions – LOL"
  1. Hello Tony, good morning

    I have a question about “Lane Mapping”, I am running a 100G test with an EXFO 85100G equipment

    If I change manually the PCS lane, and I sent the same information by two different channels, the test show Inv Mapping, and after NO TRAFFIC.

    I understand that this is OK, because a same traffic in 2 o more lanes is a mistake.

    But the question is….Exists, in a IEEE802.3ba, a paragraph, which indicates that an INVALID MAPPING, involve a traffic affecting??

    I am looking this in IEEE802.3ba, but I can not find it..

    Thank you Tony, best regards

    JERF

  2. Hi there Jerf,
    I don’t believe that is specified in 802.3ba as the alarm conditions defined there are based on conditions being met in the received signal. However in the case where there are duplicate PCS lanes containing duplicate blocks being received in a device then the link will fail and traffic will not pass through the link as it will not be possible to recombine the PCS lanes (as one of them is completely missing). Therefore it will not be possible to construct complete Ethernet frames in the receiving device so you would lose all your traffic.

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