Understanding the condition of the PCS lanes is crucial to troubleshooting 100G links during network deployments. At the most basic level understanding that there are errors at the PCS indicates that the root cause of the fault lies with the physical signalling and not at the MAC layer or any of the high network layers […]
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 […]
100G Ethernet includes a process that continually monitors the performance of received PCS data and triggers an alarm condition in the event that an excessive error ratio is detected. When receiving data at the PCS each lane is checked for errors in the 2 bit sync header in each 66b block. A counter is maintained […]
At 100G speeds OTN uses a multilane implementation to achieve the OTU4 client interface. Using these multilane interfaces can present a number of challenges and new defect conditions have been defined to support these. LOFLANE is a loss of frame defect on a logical lane. In some ways it is similar to Loss Of Block Lock […]
The alignment marker is used for the identification of the PCS lanes. They allow the receiving network equipment to identify the lanes as they are received so that that they can be re-ordered. So what is an alignment marker? An alignment marker is a single 66 bit block that is inserted into the stream of […]
On the 100G Ethernet interface the Loss Of Block Lock (LOBL) alarm is raised when it is not possible to lock onto the sync. header within the 64b/66b line coded blocks. As the serial stream of blocks are distributed over the 20 PCS lanes during transmission the LOBL alarm should be reported within a specific […]
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