Cisco 2950 swich blinking in red and green

Unanswered Question
Apr 23rd, 2008

I have one 2950 switch connected to router fastethernet.

But the problem the port in switch which is connected to router is continously blinking in green then red .

In switch console there is no message showing interface up down . pls help regaring this.

I have this problem too.
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fherlan Wed, 04/23/2008 - 09:17


I sometimes had that issue when the connected device and the switch port could negotiate speed/duplex propperly.

Do you get messages like "duplex mismatch"?

Then you could lock both ports to e.g. 100FDX.

Hope it helps.



Yudong Wu Wed, 04/23/2008 - 10:36

Did you see any message regarding to duplex mismatch?

Is it blinking in green then red or green then amber?

Here is the info in installation Guide.

Alternating green-amber:

Link fault. Error frames can affect connectivity, and errors such as excessive collisions, CRC errors, and alignment and jabber errors are monitored for a link-fault indication.


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