[c-nsp] What would give a up down on ethernet

[Hakan Lindholm]

On Sat, 2 Apr 2005, Michael Smith wrote:

>> From: "Voll, Scott" <Scott.Voll at wesd.org>
>> Date: Mon, 28 Mar 2005 07:45:40 -0800
>> To: <cisco-nsp at puck.nether.net>
>> Subject: [c-nsp] What would give a up down on ethernet
>>
>> What would give me a FastEthernet0/0 is up, line protocol is down on an
>> Ethernet interface?
>>
>> I'm not sure what kind of switch it is but it's a cisco 2621 on my end
>> and it was working Friday but is now not working.
>>
> The interface is administratively up and link has been detected, but some
> issue is causing the integrity of the link to be degraded enough that it
> cannot be properly established.  This is probably just one of several
> reasons, but it seems likely given the fact that it worked at one point.

This is very common with SDH, but now you are talking about Ethernet :)

I have seen this when a media converter (SX-TX) gives link but the remote 
switch is not available.

Remote <--fiber--> mediaconv <--copper--> Switch

Pull the fiber and some mediaconv will still give Switch link up/protocol 
down.

/H