Interface Speed Local pair Pair length Remote pair Pair statusДЇa0/6 auto Pair A 31 +/- 1 meters N/A Open TDR test last run on: February 12 04:45:37 Sw1#show cable-diagnostics tdr interface fa0/6 Use 'show cable-diagnostics tdr' to read the TDR results. sw1#test cable-diagnostic tdr interface Fa0/6ДЄ TDR test can take a few seconds to run on an interface the following is good tdr output for the command when nothing is connected to the other end of the cable. If you have a Cisco switch, you can test your cabling on the up / down interface like this. If the cable is faulty, it could cause up / down status That said, I do have vague memories of seeing up / down when the remote interface was shut on other platforms in the past, but I don't remember seeing it recently sw1#sh ip int brief | i 0/1ДЇastEthernet0/11 unassigned YES unset down downДЇastEthernet0/12 unassigned YES unset administratively down down then I connected a good cable between the fa0/11 and fa0/12 ports. For example, I have a c3560c in my lab and shutdown fa0/12. is good cable that connected to both switches, but one switch had it's interface in 'administratively down' state, will cause that situation?.

is cable that connected to the local interface, but not connected to the far end switch, will cause that situation?.Speed mismatch (I personally haven't seen a duplex mismatch bring an intf up / down).If you're seeing up / down, the most likely causes are: I wonder what can cause that the first line output of the command 'show interfaces' will be: 'fastEthernet is up, line protocol is down'.Д¬isco ethernet interfaces are normally down / down if they don't have a link.