Identify the switch port type: Determine the type of fiber optic port (XFP, SFP, SFP+, QSFP+, etc. This information is usually found in the switch's documentation or on its physical labeling. Fiber optic switches utilize. Note down the port numbers of the fiber interfaces you want to check. Use the "show interface <interface_number>" command to display detailed information about a specific interface. The dilemma here is to find out if these are ethernet connections & if they are fibre, are their any SFP's connected on the port. What i understand is if the interface shows 10/100/1000 TX - it. This document describes how to troubleshoot fiber optic interfaces by addressing some of the fiber optic module and cabling specifications. SFP transceiver modules almost always require two fiber optic cable strands.