Remove and reinstall the optical fibers and optical modules and check whether the fiber connectors are damaged or contaminated, to determine whether the CRC error packets are caused by poor contact. That is, the CRC error packet statistics indicate the number of times the verification nodes obtained by the transmit and receive ends using the CRC mode do not match. This engineer is trouble shooting optical transceivers. When you found the following. We have 2 x SFP fiber single-mode uplinks to the Core. one pair is working perfectly, the other got thousands of 46920 input errors, 42586 CRC. and the switch's log shown %SFF8472-5-THRESHOLD_VIOLATION: Te1/1/2: Rx power low alarm; Operating value: -20. How do we. Customers in the use of optical modules will more or less encounter a variety of failure problems, such as optical module model selection is correct, the use of jumper is correct and some common problems, customers have the ability to judge and have a clear solution, but for some of the use of. Optical transceivers—such as SFP, QSFP, and OSFP transceivers —are essential components in high-speed data center and enterprise networks. These fiber optical transceivers convert electrical signals into light and back, enabling long-range, high-bandwidth communication over fiber optic links.