Odd Speed Issue Related to Cable Connection

[rmiller1959]

Well, it appears that my Internet connection speed problem has returned. I want you to see the speed difference between the last two Speedtest runs, and the time that elapsed between them:

What happened between 2:17 pm and 2:18 pm? I got up, walked across the room to my router, unplugged my computer from it, and plugged it back in within a few seconds. I walked back to my desk, ran Speedtest and got the results you see at 2:18 pm. That has to be the RJ-45 connector, right?

I should add that, prior to running the test at 2:17 pm, my computer had been awake and in use for practically the entire day.

 

[degrub]

what did windows driver indicate the link rate was - 100 Mb/s ? or did it stay constant at 1,000 Mb/s ?

 

[degrub]

once the speed is back up, wiggle the cable on one end or the other and see if the port link lights or reported link rate changes.

Are the individual wires solidly seated in the plug on each end ?

i have "fixed" a few cases by getting a 5 port GBit switch, placing it at one end or the other of the long cable and using a short 1-3 ft cat5e cable between the switch and the device (either the router or the PC in this case).


If it is a router port hardware issue, try another port. If it is a PC port issue, get an intel card or a USB adapter and see if that fixes it.


a couple thoughts -
Was there anything going on with the weather at the time ?

Is the router plugged into a UPS in battery backup receptacle ?
Is the PC plugged into a UPS in battery backup receptacle ?

 

[rmiller1959]

Let me investigate based on what you've provided! However, I have a partial answer to some of your questions.

I have never suspected the PC. The problem has persisted on my PC exclusively through two motherboards, an ASUS Z-170P and an ASRock Z590 Steel Legend. Dramatically different platforms, same result. My wife's desktop has never had this issue, and that's with two different motherboards as well. The long network cable is plugged directly into her PC and runs to the internal switch in the router. Whenever I experience a slowdown, I always run Speedtest on her system within a minute or so to see if she's experiencing the same slowdown. She isn't.

My current configuration has a short cable going from my PC to a 5-port gigabit switch, and the long cable runs from the switch to the back of the router. The PC is plugged into a UPS in a battery backup receptacle, and I will check to see if the router is similarly situated.

The weather has been clear during the times I've observed this problem, although I hasten to add it is a random check and not done at regular intervals.

The next time the speed drops, I'll take note of the link rate.

I have tried every port on the router (it has four), so I've ruled out the router as the issue. I want to see if the unplugging and plugging of the cable on the switch end of the connection has the same impact as doing it from the router. That would certainly tell us something.

 

[rmiller1959]

Forgive the long post - it's mostly images! I finally got a chance to do some additional troubleshooting based on the comments I received previously. Here is what I discovered.

I ran a random Speedtest and discovered the download speed had dropped considerably:

I checked the link speed:

I ran another test:

I checked the link speed again:

Link speed (Receive/Transmit): 1000/1000 (Mbps)
Link-local IPv6 address: fe80::b4de:98c5:4f32:aada%12
IPv4 address: 192.168.1.62
IPv4 DNS servers: 192.168.1.1 (Unencrypted)
Manufacturer: Realtek
Description: Realtek Gaming 2.5GbE Family Controller
Driver version: 10.50.511.2021
Physical address (MAC): A8-A1-59-89-6B-F2

I then disconnected the computer from the network switch and immediately reconnected it. I ran another Speedtest:

 

[rmiller1959]

Forgive the long post - it's mostly images! I finally got a chance to do some additional troubleshooting based on the comments I received previously. Here is what I discovered.

I ran a random Speedtest and discovered the download speed had dropped considerably:

View attachment 37361

I checked the link speed:

View attachment 37363

I ran another test:

View attachment 37364

I checked the link speed again:

Link speed (Receive/Transmit): 1000/1000 (Mbps)
Link-local IPv6 address: fe80::b4de:98c5:4f32:aada%12
IPv4 address: 192.168.1.62
IPv4 DNS servers: 192.168.1.1 (Unencrypted)
Manufacturer: Realtek
Description: Realtek Gaming 2.5GbE Family Controller
Driver version: 10.50.511.2021
Physical address (MAC): A8-A1-59-89-6B-F2

I then disconnected the computer from the network switch and immediately reconnected it. I ran another Speedtest:

View attachment 37365

Finally, I disconnected the main network cable from the switch and reconnected it. Here is the Speedtest result:

This is the same result I get if I disconnect the main cable from the router. I can only conclude that the cable is the issue, correct?

 

[L&LD]

The cable may still be the root cause, but I would fully power down the switch (unplugging all LAN and power wires) for at least a few minutes too.

It may also be the cable + switch combination too.

 

[degrub]

Is the link rate changing between the switch and the router port during this time ?
The link rate between the PC and switch looks normal at 1 Gbit/s
Usually, the port lights will indicate if you cannot log into the switch or router and monitor.

And you have tried multiple ports on the switch for the cable to the router ?

One way to confirm the long cable is the issue and not the switch ports is to get a 50 or 100ft cat5e cable ( whatever length appropriate) and connect it to the router port and the switch port. Make sure one end of the existing cable is disconnected. If the link stays at 1 Gbit/s, then likely the existing installed cable - maybe just a termination on either end which could be fixed by installing new connectors.

 

[degrub]

The cable may still be the root cause, but I would fully power down the switch (unplugging all LAN and power wires) for at least a few minutes too.

It may also be the cable + switch combination too.

In addition to what i suggested, you might just swap out the switch with a different brand 5 port Gbit switch. it could be bad power supply (wall wart block) or internal.

Make changes one at a time otherwise it is a best guess result.

 

[L&LD]

Yes, that was implied.

 

[rmiller1959]

The switch and router locations will make it a little challenging, but I can check the port lights the next time this happens.

I have tried multiple ports on both the switch and the router to no effect.

Getting a long network cable for testing purposes is a good idea! I'll look into it.

Powering off the switch for a time and disconnecting the cables from the switch is also a good idea, although the current switch wasn't always in the mix, and the problem was present with the previous switch also if memory serves.

 

[rmiller1959]

I just wanted to close the loop on this thread. I had an electrician friend redo the RJ-45 connectors on both ends of the main Cat 6A cable I was using, and my speed problems were solved instantly and, as far as I can tell, permanently. I could have saved a little time and trouble if I'd gone to that solution first!

 

[L&LD]

Thank you for the closure. As I implied in Post 3, the cable is (should be) the first suspect and is to be pursued until proven otherwise.

I should (in the future) point out that when I state 'it's the cable', it means the actual cable itself, the connections, the connectors, and the RJ45 socket they're plugging in to, too.

All are variables that can get a wired connection at suboptimal performance levels.

A quick fix/test is to reverse the cable and see if the issues persist. By 'reverse', I mean to connect each end to the other device, at least temporarily, (if possible). This is good enough to rule out connector variations issues.

If this doesn't give the expected results, testing with a new cable from a different manufacturer (and of higher quality, of course) is the next step.

Or, simply getting the ends redone as in this resolution.

BTW, did it actually take almost a full year to resolve this issue?

 

[rmiller1959]

Thank you for the closure. As I implied in Post 3, the cable is (should be) the first suspect and is to be pursued until proven otherwise.

I should (in the future) point out that when I state 'it's the cable', it means the actual cable itself, the connections, the connectors, and the RJ45 socket they're plugging in to, too.

All are variables that can get a wired connection at suboptimal performance levels.

A quick fix/test is to reverse the cable and see if the issues persist. By 'reverse', I mean to connect each end to the other device, at least temporarily, (if possible). This is good enough to rule out connector variations issues.

If this doesn't give the expected results, testing with a new cable from a different manufacturer (and of higher quality, of course) is the next step.

Or, simply getting the ends redone as in this resolution.

BTW, did it actually take almost a full year to resolve this issue?

It didn't take a year, but it took too long given the simplicity of the solution, and I give you props for pointing it out very early on. A combination of factors, including the availability of my electrician friend who installed the wiring in the first place, extended this problem by seven months and nine days!

Even my electrician friend wanted to examine other options before the one that worked. Maybe he didn't want to believe his installation was faulty! I reminded him that we switched connector brands in the middle of the installation because he found the initial brand I bought more problematic when terminating the Cat 6A cable. When he used the 2nd brand to re-terminate my cable, the problem was resolved. I asked him to do the same for a couple of other cables where he had used the 1st connector brand.

 

[Tech9]

extended this problem by seven months and nine days!

Crimper and 100 pass-through connectors start from $30 on Amazon.

 

[rmiller1959]

Crimper and 100 pass-through connectors start from $30 on Amazon.

I bought both connector sets from Amazon, along with the cable and other components. My electrician friend brought his own crimping tool!

The first brand was Cable Matters, a 50-Pack of RJ45 shielded modular plugs with strain relief boots. Those are the ones my friend said he had difficulty terminating.

The 2nd brand was ITBEBE, also a 50-pack of gold-plated end pass-through RJ45 connectors for Cat6, Cat6a, and other 23 AWG cables. He said they were much easier to work with.

I don't know the difference and both were well-rated on Amazon, but I trust my electrician friend! Maybe it was the pass-through design for the wires that made it easier.

​

 

[Tech9]

I trust my electrician friend!

This person couldn't find the time to stop by and help a friend for 7 months... I would just do it myself. 8 wires inside the cable, color coded.