Two SG300 Switches, LC-LC fiber and 1320nm Adapters

[tourtelot1]

I am pretty certain that this has worked in the past but I'm am needing to go to fiber (instead of copper) for a long run at an entertainment venue.

Ports 27 and 28 on the SG300-28 switches are trunked as is port 10 on the SG300-10, 2x VLANs on all switches.  Ethernet connection works fine.  Fiber works fine between one SG300-28 and an SG300-10.  Adapters work between one SG300-28 and the SG300-10.

When I plug in the ethernet cable, the right port light shows a solid green and devices on the outboard switch are "seen".  When I plug in the fiber, the right port light flashes green at a steady beat.  No devices on the outboard switches are "seen".

Thoughts please.

Thanks.

Doug

[tourtelot1]

More info.  I drug out the spare SG300-28 and the 1310nm adapters and fiber work just like they are supposed to.  So that points to one particular SG300-28 as the problem child.

Is this some managed mis-setting by me or is that part of this switch broken?

D.

[marce1000]

    - Check logs on the device when the intended connections are made  , check if you can find more info's

 M.

[tourtelot1]

Thanks.  I'll take a look.  I will try and simplify the problem today and check the log.  Can I assume that I can plug the computer running the Cisco browser directly into the switch that has the issue?  I can not connect over a simple switch to switch network because, well, it doesn't work.  Interesting that the trunk ports, 27 and 28, work with a copper connection but not with the fiber adapter.  An identical switch, set exactly the same (via a download of the problem switch's setting a while back), works as it should.  So I suspect an actual electronics fault in the problem switch at this juncture.  What does the flashing green Gigabit lamp to the right of the port indicate?  The manual has explanations of two states, on and off.  No mention of flashing<

I do notice that the two trunks on both switches in the simple network are set to "tagged" on VLAN #1 and "untagged" on VLAN #2.  I set this up a few years ago and don't know if this was changed somehow over the ensuing years.  In my documentation of settings, I listed all VLAN's trunks as being "tagged".  May not have anything to do with the problem and I do know that both VLANs have been working as they should recently via copper.

I'll get back later today with a screen shot of the log and of the diagnostics page.

Thanks!!

Doug

[marce1000]

                       >....What does the flashing green Gigabit lamp to the right of the port indicate

  - Normally this could indicate that the port is just passing traffic , not sure if that 'coordinates' with the other problems you are observing.

 M.

[tourtelot1]

Hi-

I believe you might have interpreted my LED question backwards.  There are two LEDs on Port 27 and 28 (and all the rest).  The left-hand LED, labeled LINK/ACT and that, I believe, shows network traffic.  The LED I am speaking of is the right-hand LED, labeled GIGABIT, that seems to stay in a steady green state when working correctly, but in the case of the problem switch, pulsates at a regular beat.  With a copper connection to another switch, the right LED on the problem switch is steady green.  With a fiber connection in the same port, the GIGABIT LED pulsates.

I have done extensive testing this morning with all four of my SG300 switches and the problem switch is the only one that misbehaves.  I am coming to the conclusion that the fiber ports on this switch are broken.

Do you know if Cisco still does a lifetime warranty on these switches.  Repairs?  If so, who do I contact at Cisco?  If not, I will need to sell it "as-is" (and except for the fiber issue, it seems to work as it should) and look for another to purchase.

Oh, and I could not find a way to print out a log in the browser so I can't add anything there.

Thanks so much for your continued help on this.  I really appreciate it.

Doug 

[marce1000]

 - For warranty info's . check this thread : https://community.cisco.com/t5/small-business-switches/sg300-series-warranty/td-p/3257148 , look at reply from   Martin Aleksandrov

 M.

[tourtelot1]

Okay, I found out why the switch is doing what it is doing.  My next request is to figure a work around to solve the problem.

This switch is used in the live room of a recording studio in a closed Dante Audio Over IP situation.  The fans in the switch were too loud in the room and I added a switch backed up with some power resistors to slow the rotation of the fan down by maybe 50%.  Noise was no longer an issue, particularly.  The switch is in it's own rack case, ventilation on all six side and never even gets warm to the touch under its most extreme use.  When I have the switch fans running half speed, I get the flashing "FAN" LED.  That means that the switch recognizes a fan issue.  I live with the flashing LED.

But, when I switch the fan to half speed, the switch works fine with copper but will not allow the fiber adapter to load.  Copper still works fine.  Turn the fan back to full speed and the fiber port works.

So I have two other SG300 switches with the same resistor/switch setups and they all work fine with the fiber.  And they never get hot.  

Is there any way to have this particular switch to allow fiber port access if the fan is running half speed?  Why does this not cause the same issue on my other switches?

Here is a screen shot of the activity on the affected switch as I change the fan speed and change from fiber to copper.

Doug

[tourtelot1]

Sorry that I seem to be the only one replying to the thread but as I try new things, I'll add them to the information stream.  I just took out the fans/resistor network and replaced them with Noctua quiet fans.  Wired them as per instruction with the green "sense" wire in the middle of the connector.  Well, the good news first.  They are very quiet.  As quiet as the 50% fans before but pushing a lot more air.

The bad news is that the sensor wire does not seem to do the job.  The fan failure LED flashes and I get fan failure notice in the logs.  Sometimes, without the fiber plugged in, the fan LED will go solid green but reverts to flashing on its own and always when I connect the fiber to the adapter.

Doug

[tourtelot1 · Accepted solution]

Okay, last post on this thread.  The solution was to buy a slightly earlier version of the SG300-28P.  I put the Noctua fans in; quiet as a mouse.  Yes, yellow flashing system LED.  But the fiber adapter links and the transmission seems 100%.

Now, the other switch was an SG300-28-PP (PoE+) which I don't need and may have had something to do with my problem.  

Anyway, it took me a while but if anyone ever has a similar need, this is how I did it.

Doug