Cabling Question

mmillington_nal · ‎10-26-2012

I have a question regarding cabling. What would the symptoms be if I were experiencing interference in my cabling? We are having some issues with some devices in our manufacturing area. I see no errors on the switch port, yet there is intermittent connectivity and some packet loss (approx 1%). Windows will report connection drops then comes right back up but it breaks the applications connection to the server so its impacting them.

The cabling is running along with power cables, not in the same conduit, but very close to each other. Also, as a manufacturing plant, it is a very noisy environment with many machines running. Cable is outside of conduit for much of the runs.

What kind of things should I be looking for to figure out whether its cabling, device NIC, etc?

TIA,

Matt

Reza Sharifi · ‎10-26-2012

Matt,

If you are running copper that it can be susceptible to electronic interference. If you are running fiber, than you don't have to be concern about inference. Also distance can be an issue. If you are running copper the distance is usually around 100 meters. With fiber, it depends on multimode or single mode.

If using fiber, check and clean the connectors and the optics.

HTH

mmillington_nal · ‎10-26-2012

Reza,

Thanks. It is copper, and its within 100 meters. I am worried about the interference, but I'm not sure how I can detect that or measure it. How would I be able to tell if there is electronic interference?

Thanks,
Matt

shillings · ‎10-26-2012

Chances are it is interference. A cabling contractor can test it and tell you if it passes or not, but it might be cheaper just to re-run it.

mmillington_nal · ‎10-26-2012

Would my symptoms be what I'm seeing? No ethernet errors but there are output drops, and some packet loss and intermittent connectivity at the OS level?

Thanks,

Matt

shillings · ‎10-26-2012

Output drops signify the egress buffer was full.

You can increase the size of the output queue, but Cisco recommend you leave it alone.

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a0080094791.shtml

You can configure QoS to prioritize particular traffic.