So the old IT guy was a college student with no experience prior to be hired beyond some classes. The one before him had no experience at all and just did his best with what he had. Now I am here and we have some really bad packet loss problems... I bought a network cable tester, I would have like a certifier but there was no budget for that, and it shows that from the wall outlet to the patch panel the wiring goes as follows. 12345678--->21654387 The connections work but every connection fails because the pairs are switched. Every pair. Should I tear apart the patch panel and fix all of the switched pairs? It looks like from my research that they are just a polarity switch, send+ to send- and receive+ to receive-... I just want to make sure that this is a good reason for packet loss. And that fixing this will lead to a resolution of my current nightmare.

  • Fascinating - this question seemed to suggest that it might not matter. Now you have evidence that it does. – Andrew Jun 3 '15 at 6:47
  • How many ports are you experiencing the wiring problems on? 24? more? less? Also: at which speed are you operating your network? 100 Mbps? Also: which ethernet switch are you using? Is it "managed"? I'm asking 'cause I suspect the wiring problem is NOT the only problem you have and, also, if packet loss suddenly appeared recently, is NOT the source of your problems. – Damiano Verzulli Jun 3 '15 at 17:26
  • Packet loss has been occurring for some time, I started an SNMP monitor on the switch and saw massive amounts of packet loss to the tune of 3,000+ per second. The company has had "internet" problems since the beginning, they blamed Comcast and an office with an average of 20 people in it at any given time now have 150mbps connection. They average about 4mbps of usage peaking at about 30mbps. Needless to say it is costing them a fortune. – Eli Webster Jun 3 '15 at 17:59


Absolutely that'll be the problem.

You need to rewire both ends so that they match either the 568a or 568b standard. Not wiring it correctly will result in the errors you describe because it relies on differential signalling for noise free transmission. Don't worry if you don't understand that. Basically a plus and a minus pair are twisted together inside the cable.

I'd start with a jack at a time.


  • 1
    I have 5 years experience in networking, I have just never been clueless enough to mess up wiring on this scale. Honestly I was just surprised the connections worked at all. – Eli Webster Jun 3 '15 at 4:51
  • Maybe the guy just thought that connecting wires is enough and it doesn't matter which ones. – Matt Jun 3 '15 at 4:56

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.