The possible reason is that the remote interface is Down or packets sent from the remote interface are dropped during transmission. The table describes the LED status indicators for Ethernet modules or fixed-configuration switches: Ensure that both sides have a link. A single broken wire or one shutdown port can cause the problem where one side has a link light, but the other side does not. Check compatibility between the optical module and switch Most switch brands have specific compatibility requirements. Usually, the port status failures are manifested as four types: the port is down (link failure), no packets received or sent when the port is up, unstable link, and CRC errors. You can troubleshoot those issues from the following four perspectives: Take the 10G SFP+ optical modules as an example. SFP issues are among the most common and frustrating problems in fiber optic and Ethernet networking environments.
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