Connection works at 100Mbps

Wizard!

We recently moved to a new house and we had an electrician data wire all the rooms.
We installed a double Cat 6 RJ45 wall plug in every room and all the cables, 14 in total, end up in a storage room where we have a Gbit switch.


Some of them, although they past the "network cable tester" test, do not work at 1000 Mbps, instead they work at 100.


Since the cable tester, reports all cables are connected and work, what can be wrong?


Maybe wrong pairing?
He didn't follow any of the T568A/B connection methods?


All hardware (wall plugs, cables, connectors) is supposed to be Gbit certified (Cat 6)

smuggler.ie

Wizard! wrote: »

We recently moved to a new house and we had an electrician data wire all the rooms.
We installed a double Cat 6 RJ45 wall plug in every room and all the cables, 14 in total, end up in a storage room where we have a Gbit switch.


Some of them, although they past the "network cable tester" test, do not work at 1000 Mbps, instead they work at 100.


Since the cable tester, reports all cables are connected and work, what can be wrong?


Maybe wrong pairing?
He didn't follow any of the T568A/B connection methods?


All hardware (wall plugs, cables, connectors) is supposed to be Gbit certified (Cat 6)

It takes two devices(on each end) to support Gbit for link to work @1000MBPS
What device you do speed test with?

Wizard!

smuggler.ie wrote: »

It takes two devices(on each end) to support Gbit for link to work @1000MBPS
What device you do speed test with?

I know the basics

On one end, there is a Gigabit switch and on the other ends, the one with the issue, I have my main PC with an Intel I219v Gigabit Ethernet controller, or my laptop with a Broadcom BCM5720 Gigabit ASIC chip.

Both tested with another small TP-Link switch, directly connected, that work at 1Gbps

Do you trust the electricians that installed it? CAT6 is a lot less forgiving than CAT5E when it comes to rough handling.

Wizard!

ronoc wrote: »

Do you trust the electricians that installed it? CAT6 is a lot less forgiving than CAT5E when it comes to rough handling.

Not really, no. But at the time, I had no other option because we needed to move in soon.

I have the knowledge and tools to replace connectors and wall plugs, but the question is: could this be the issue?

Alun

Wizard! wrote: »

Some of them, although they past the "network cable tester" test, do not work at 1000 Mbps, instead they work at 100.


Since the cable tester, reports all cables are connected and work, what can be wrong?


Maybe wrong pairing?
He didn't follow any of the T568A/B connection methods

My money would be on the last one.

These so called cable testers that just measure DC connectivity end to end are useless unless you are 100% certain that you have wired each end of the cable correctly. Usually it's the two middle pairs that are wired incorrectly resulting in a so called "split pair".

smuggler.ie

even cheap tester like that would tell you if wires swapped around or not punched/crimped properly.

Alun

smuggler.ie wrote: »

even cheap tester like that would tell you if wires swapped around or not punched/crimped properly.

It would tell you if, say, pin 1 on one end was connected to pin 3 on the other, maybe, but that's not what I'm talking about.

It's all about the pairs and the twisting of those pairs which is vitally important for error free signal transmission to reduce crosstalk.

What often happens is that the plugs/sockets are wired so that each pair is wired to pins 1&2, 3&4, 5&6 and 7&8 which is wrong.

It should be 1&2, 3&6, 4&5 and 7&8 following TIA 568.

What you get there is a situation where one signal goes down pin 3 of one pair and comes back via pin 4 of another, where in fact it should be coming back via pin 6 on the same pair, ditto for the other pair, in other words a split pair.

This results in crosstalk between two signals and unpredictable results.

smuggler.ie

Wizard! wrote: »

We recently moved to a new house and we had an electrician data wire all the rooms.
We installed a double Cat 6 RJ45 wall plug in every room and all the cables, 14 in total, end up in a storage room where we have a Gbit switch.

@Alun I hear you.
Worth to pull off plates and check your version and/or ...if electrician didn't actually split one cable for two ports.

Wizard!

smuggler.ie wrote: »

@Alun I hear you.
Worth to pull off plates and check your version and/or ...if electrician didn't actually split one cable for two ports.

No, he didn't, as I was here few times and clarified few things. Also, there are 7 plugs and I have 14 cables, so...

Wizard!

Wizard! wrote: »

We recently moved to a new house and we had an electrician data wire all the rooms.
We installed a double Cat 6 RJ45 wall plug in every room and all the cables, 14 in total, end up in a storage room where we have a Gbit switch.


Some of them, although they past the "network cable tester" test, do not work at 1000 Mbps, instead they work at 100.


Since the cable tester, reports all cables are connected and work, what can be wrong?


Maybe wrong pairing?
He didn't follow any of the T568A/B connection methods?


All hardware (wall plugs, cables, connectors) is supposed to be Gbit certified (Cat 6)

Check the switch isnt set to auto negotiate or even set to 100M.

Wizard!

Deleted User wrote: »

Check the switch isnt set to auto negotiate or even set to 100M.

It is in auto, however if I set manually the speed to 1000, it gets disconnected (my pc)

smuggler.ie

Wizard! wrote: »

It is in auto, however if I set manually the speed to 1000, it gets disconnected (my pc)

So you have managed switch(make/model?)? Or is it on PC you changing the setting?

Wizard!

smuggler.ie wrote: »

So you have managed switch(make/model?)? Or is it on PC you changing the setting?

Two switches, one managed and one un-managed.

smuggler.ie

Wizard! wrote: »

Two switches, one managed and one un-managed.

Test your network with un-managed would be fastest i think...

galvo_clare

100%

Had the exact same issue and was getting 100MB. Crimped them up properly myself with the right twist and a solid 1000 was the result.

Alun wrote: »

It would tell you if, say, pin 1 on one end was connected to pin 3 on the other, maybe, but that's not what I'm talking about.

It's all about the pairs and the twisting of those pairs which is vitally important for error free signal transmission to reduce crosstalk.

Alun

So OP, any update? Maybe a good closeup photo of the back of one of the RJ-45 jacks?

Wizard!

Alun wrote: »

So OP, any update? Maybe a good closeup photo of the back of one of the RJ-45 jacks?

The update is, that the electrician followed T568B on the wall plugs, but T568A on the switch side where the RJ45 connectors are...
As a result I had to replace all the RJ45s, with new ones and test each cable.
So far, I can't do them all at once with two toddlers running around, the ones I changed, work at 1000 as they should.

Alun

Wizard! wrote: »

The update is, that the electrician followed T568B on the wall plugs, but T568A on the switch side where the RJ45 connectors are...
As a result I had to replace all the RJ45s, with new ones and test each cable.
So far, I can't do them all at once with two toddlers running around, the ones I changed, work at 1000 as they should.

Great news.

Wizard!

Yesterday I replaced wall plug and RJ45s (all wall plugs are dual RJ45s) for my office and today the ones where VM modem is. Before that OKLA was reporting 90/30.