[SOLVED] does a gigabit connection going from T568A to 568B slow the connection?

[daryl54]

i just got verizon gigabit, however my house in wired in 586A wires from 2004. all new cables are "B". whats weird is from the box outside the house to the wall plate ---pre router--- is 568A. a short cable goes from the wall outlet to the router and it is "B". everything plugged directly into the router runs great. where the speed is getting killed is the outbound to the rest of the house that runs through a cisco SG100-16. Is the outbound "B" from router to "A" wall plate and cable "A" to Router to "A" to wall plate back to "B" cable to equipment the issue? the cables in the walls that were builder installed are Cat 5e, Home Choice by Belden verified UL CMR or C(UL) CMG. not sure what all that means. everything else is a patch cable, cat5 or cat5e

ironically i plugged the Macbook direct to the router, with a Cat 5 only (not e) and its a 568A, and i pulled down around 850Mbps on verizons speed test. i tested the Cat5E coming from the "router to wall plate to basement," pulled it from the cicso switch and direct to the laptop and barely get 100. maybe the cat5e wire in walls is just a bad wire? or could the wall plate be an issue? logically i believe the pairs swapping orientation are an issue, tho dont understand why it wasnt an issue close by. i even have a second switch in the office, as the 4 port on the router wasnt enough and tested that. basically to the wall plate its "A", then "b" to the router, then "B" to a switch 3 feet away, then cat5 only A to the macbook, and stll pulled over 800Mbps....which seems to say going back and forth isnt the issue leaving me with more questions than answers.

here is my other thoughts. my network cables are green, and the phone are blue. it was one of those old 4 cables tied together wiring in the house, black and i think white for coax. apparently the 1gig connection has to come in on cat5e, not coax like my fios use to. so they bridged 2 "A" configed cabled in the basement and used the wall plate top network jack as the "IN" for the gigabet connection to the router. this left me no "OUT" back to the basement, so i used the phone RJ45 connection from the no longer used phone module in the basement. the wires, other than color (blue vs green), are both cat5e and marked identially, however it is this blue cable in the basement that is now into the router, that isnt getting over 100mbps much, i got it to 105 for a heartbeat. is it possible the wallplate for this line, being only meant for phone, doesnt have all 8 pairs connected? if they only tied 2 pairs being lazy, would that explain my issue? thx!

 

[bill001g]

This is rather confusing.

If you have A one end of the cable and B on the other end of the cable technically you have a crossover cable. These tend to confuse the auto negotiate and many times it will drop to 100mbps. Gigabit has no concept really of cross over cables. It transmit and receives at the same time on all 4 pairs from both ends. Many times gigabit will work on crossover cables but it is hit and miss.

Now if what you mean is you have a patch cable that is A on both ends and you connect it to a patch cable that is B on both ends that makes no difference. The signals have no way to know the color of the wires and the end result is the same the signal that is connected to say pins 1,2 comes out on pins 1,2. The electrical signal only care that the wire is copper colored under the plastic. 100 pair cables used for data center patch cables have many many more colors that the 4 used. The wire pairs themselves are the same, years ago they used to be different. I think that is one of the difference between cat5 and cat5e if I am remembering correctly.

It is not uncommon for houses to have rj45 jacks wired for phones. The rj11 plug will fit into the jacks. Used to be fairly common to run 100mbps data on ping 1.2.3.6 and phone on 4,5 in the same jack. It likely has been almost 15 years since anyone did that though.

If you cables are built as crossovers I would rewire ever thing to be straight through.

 

[daryl54]

This is rather confusing.

If you have A one end of the cable and B on the other end of the cable technically you have a crossover cable. These tend to confuse the auto negotiate and many times it will drop to 100mbps. Gigabit has no concept really of cross over cables. It transmit and receives at the same time on all 4 pairs from both ends. Many times gigabit will work on crossover cables but it is hit and miss.

Now if what you mean is you have a patch cable that is A on both ends and you connect it to a patch cable that is B on both ends that makes no difference. The signals have no way to know the color of the wires and the end result is the same the signal that is connected to say pins 1,2 comes out on pins 1,2. The electrical signal only care that the wire is copper colored under the plastic.

It is not uncommon for houses to have rj45 jacks wired for phones. The rj11 plug will fit into the jacks. Used to be fairly common to run 100mbps data on ping 1.2.3.6 and phone on 4,5 in the same jack. It likely has been almost 15 years since anyone did that though.

If you cables are built as crossovers I would rewire ever thing to be straight through.

Thanks for the reply! i didnt think to clarify that, they are not crossover cables, it is a "A" cable changing to a "B" cable either via wall plate connection, router or switch. the phone connection is a RJ45 and the wire behind it is a cat5e...what i havent confirmed is did all 4 pairs get connected in the back of the wall plate. I didn't know that the "A" to "B" patch cables would not cause an issue, that is super helpful and is one more thing i can rule out.

i saw another post where electrical wires were causing interference, thankfully my basement isnt finished, the electrical panel for the the house is near where some of these wires run, could that also cause a significant lag in speed if too close? is there a recommended seperation distance? thx!

 

[bill001g]

The twist in the wire are designed to prevent interference. In general you would have to wrap the ethernet cable around the electrical power for it to cause issue. Most times as long as you meet the electrical code which is for safety reasons you will never get interference. A couple inches is fine when the run in parallel. There is no issue with them crossing. When we used to put like 30 1u servers in a rack and each had 2 power cords and 3 ethernet jacks each we had massive amount of ethenet and power cords in close proximity and never saw any issues.

 

[daryl54]

The twist in the wire are designed to prevent interference. In general you would have to wrap the ethernet cable around the electrical power for it to cause issue. Most times as long as you meet the electrical code which is for safety reasons you will never get interference. A couple inches is fine when the run in parallel. There is no issue with them crossing. When we used to put like 30 1u servers in a rack and each had 2 power cords and 3 ethernet jacks each we had massive amount of ethenet and power cords in close proximity and never saw any issues.

ok, thank makes a lot of sense. i think i need to rule out the physical connection at the wall plate then, as the wire connected to it, on the far end, isnt breaking 100, and the wire connected into it from the router, when plugged direct to a laptop, gets over 800. if not that wall plate physical connection, then i think that only leaves a bad wire? not sure what else to rule out. thanks for your help!

 

[bill001g]

It is extremely common for a jack to not work just because one wire is slightly loose. It could be the insulation was not cut when the wire went into the punch down. Repunch all the positions to be sure. You can also cut off about 1/2 inch and repunch down jacks pretty easy. RJ45 plugs are another story those you have to get all 8 wires correct the first time or you cut it off and restart.