General discussion


Bad Fiber in my Infrastructure.....

By TypeOctoberRust ·
I recently replaced 2 network hubs with a 48 port 3560 Cisco Switch. Everything seems to work great on that switch. I have another switch in the same black box, a 2950, that after installation of the new switch, started having issues with dropped packets and erratic ping times. The configuration on this switch has not change in at least a year. Also note that these switches are both on seperate fiber runs back to our main 6509 switch. After a reboot of the 2950 and a little fixing up of the fiber cables, the ping times seem to be a lot more stable, and no dropped packets.

My question is does this sound like a bad fiber patch cable? Also, I'd like to mention I rechecked the ends of the fiber patches on both the main and the 2950 switch, and all seemed to be securely fastened. Can fiber get pinch and cause loss of packets or is it more like the old 2950 switch needed to reboot to clear its tables from the old connected two hubs? Let me know what you think.

This conversation is currently closed to new comments.

Thread display: Collapse - | Expand +

All Comments

Collapse -

Have you tried an OTDR?

by davidpmartin In reply to Bad Fiber in my Infrastru ...

It sounds like you might have some problems with the fiber. The only way to make sure that your fiber is OK is to test it with a Optical Time Domain Reflectometer (OTDR). It will send a beam of light down to the distant end, and tell you how much you are getting back. If the loss is too high, you have bad fiber, and it needs to be replaced. If the fiber check out good, my second guess is a bad 2950. But you will not know unless you check out the fiber.


Collapse -


by TypeOctoberRust In reply to Have you tried an OTDR?

Any cheap solutions to do this? Without buying a $10,000 Fluke meter. I have an old cat 5 OneTouch 10/100 network assistant fluke meter. Any attachments to connect fiber? I know we had our fiber phyisically run by an outside company. The only dealings we have with it, are the fiber patch cables to the switches.

Collapse -

How about

by dafe2 In reply to OTDR

Just getting someone in to test them?

I just brought in a Nordx/CDT guy for less than 200 dollars ca.

Collapse -

Think Smaller

by trrrr In reply to How about

Auto sensing 10/100. Maybe duplex issue. Causes exactly what you describe. A piece of dust smaller than the eye can see can cause fiber problems. Yes reboots do help sometimes but make sure no-one is in the mioddle of a mission critical task.

Related Discussions

Related Forums