Execute the following command to view detailed interface and optical module status: ethtool <devname> The output includes interface rate, module rate, link status (Link detected: yes is required for normal module operation), and interface configuration details. In addition to independent devices such as switches and routers, optical modules can also work on network adapters (commonly known as network cards). The working rate, duplex mode, and negotiation mode of the two ends of the optical interface are different. Optical modules typically have an electrical interface on the side that connects to the inside of the system and an optical interface on the side that connects to the outside. The Cisco Small Business Series Switches allow you to plug in a Small Form-factor Pluggable (SFP) transceiver in their optical modules to connect fiber optic cables.
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