Sometimes you log onto a switch remotely and need to know what kind of optical interface the switches actually have plugged in. It’s pretty simple:
Switch#show interface gi1/0/25 capabilities GigabitEthernet1/0/25 Model: WS-C3750G-24TS Type: 1000BaseLX SFP Speed: 1000 Duplex: full Trunk encap. type: 802.1Q,ISL Trunk mode: on,off,desirable,nonegotiate Channel: yes Broadcast suppression: percentage(0-100) Flowcontrol: rx-(off,on,desired),tx-(none) Fast Start: yes QoS scheduling: rx-(not configurable on per port basis), tx-(4q3t) (3t: Two configurable values and one fixed.) CoS rewrite: yes ToS rewrite: yes UDLD: yes Inline power: no SPAN: source/destination PortSecure: yes Dot1x: yes
The most important things here is that you can see I have a 1000BaseLX SFP installed.