Hi, I am hoping someone here can help me out with an SFP Problem.
I had a setup that was working fine.
MikroTik CCR-1009-8G-15-15+ ↔ Cisco SG200-50
The trunk between the two was an optical SFP1G-SX-85. I just got back to my studio after being away for a few months and the connection was down. My trouble shooting shows the following:
MikroTik: link OK, Auto negotiation failed.
I disabled auto negotiation and set to 1Gbs (at both ends)
a cable test shows ‘link OK’
If I unplug, or disable the Port at the Cisco side the MikroTik sees the connection go down and the cable test fails.
If I swap over the individual fiberoptic connectors the link shows as ‘no link’.
Cisco: Module present no connection. No blinking lights. The port is enabled but down, and does not come up.
I have played with turning off auto negotiation and have changed the speeds, I am defaulting to 1gbs full duplex on both ends.
So, in summary, there seems to be a fiber connection and if I unplug an SPF Module, single cable (of the pair), or swap the cables, I can see that there is ‘no link’. In the MikroTik traffic graph, I see packets been sent, but nothing comes back…
This leads me to believe that it is not a physical problem.
It just seems like the Cisco is not responding to the MikroTik? As far as I know nothing has been changed in the time I was away…
Can anyone throw any light on this? Or suggest some trouble shooting steps?
The fact that you can swap the cable ends tells me the fiber might not be as protected as it ought to be, and that you are now on the cusp of learning a lesson that I, too, learned, at a significant cost in time and aggravation.
When I say swap the cables, I only mean unplug the fibre from the SFP swap the send/receive around.
The cable is buried about 30cm down in a tube so that I can pull a new cable through if necessary, so I don’t think it is being walked on that is doing it… but the cable might be damaged…
I thought that as the MikroTik is saying ‘Link OK’ then cable is probably physically intact. Is this not a correct assumption?
I’d be willing to go along with that guess, but if you can get the two devices close enough and you’ve got a known-good shorty around, I’d try that just to be sure.
Assuming the cable’s good, my next-best guess is that something got lightly fried or fell over the edge of the bathtub curve while you were away. Prime candidate is your nine-year-old router. For one thing, electrolytic caps don’t last forever.
Yes. It could just be that it’s old. It is also in a cupboard that is susceptible to climate change and it was pretty hot this year. I am using the copper ethernet cable I laid as a back up and things are working, although a little slower than previously with big file copies.