I am a bit lost. I'm trying to find the physical interface speed that is negotiated on a Gigabit interface on a Cisco 2900 and 3900 series ISR G2.

On a switch, I am used to giving sh interfaces status which gives the speed, and wether it is fixed or negotiated. However, this command is only usable on switch ports, and so it is not available on L3 interfaces.

The show interface only gives me the info that the speed is set to "auto".

Where can I find what speed is negotiated?

  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Commented Aug 8, 2017 at 9:59

1 Answer 1


The command show interface should be showing you the information you are looking for.

router#show ver | i 29
Cisco IOS Software, C2900 Software (C2900-UNIVERSALK9-M), Version 15.3(2)T, RELEASE SOFTWARE (fc3)

router#show int | i Giga.*up|Duplex
GigabitEthernet0/0 is up, line protocol is up
  Full Duplex, 100Mbps, media type is RJ45
GigabitEthernet1/0 is up, line protocol is up
  Full Duplex, 1Gbps, media type is internal
  • I would think so but the output only shows me that the speed and duplex are auto.. output Auto Duplex, Auto Speed, media type is RJ45
    – user209
    Commented Jul 20, 2013 at 10:26
  • 1
    Can you paste the full 'show interface <interface>' command output to pastebin.com and post the provided link in your original question. Commented Jul 20, 2013 at 10:34

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