3825 router Fiber Connection

Unanswered Question
Apr 2nd, 2007

We installed a 3825 router with an SFP fiber connection and the fiber didn't come up. The media-type was set to SFP and speed was autonegotiate. I had to revert back to my previous config of having the fiber go through a fiber to ethernet converter and connecting it up using ethernet.

I would like to connect the fiber directly to the router... What can I do to get this to work??? Is there something I'm missing on the port config, should I have shut the port down and back-up again?? Any clues??

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Paolo Bevilacqua Mon, 04/02/2007 - 07:59

SFP type ? Fiber type ? Span length ?

Anyway, it's always better to used fixed speed, and yes shut/no shut in some case can help.

Paolo Bevilacqua Mon, 04/02/2007 - 10:28

What is the span length ? What is the transmitter on the other side ? if it is very powerful it may be saturating the receiver, so you need to use an inline optical attenuator.

Please see this link for info:


Also, show interface, show controller x/y would be useful.

Hope this helps. Please rate posts using the scrollbox below!


This Discussion