AC86U Intermittent Speed Issues / Cable Issue?

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Jbennett360

Regular Contributor
I posted at the beginning of this month regarding an issue i had with speed (https://www.snbforums.com/threads/rt-ac86u-merlin-fw-384-16-speed-issue.64508/)
originally i thought this was a FW issue and have since flashed back to 100% stock after doing a hard reset.

To sum it up.

I have a AC86U, which has a cable that runs to an ethernet port on the wall, the cable from the back of this box then runs outside the house, over the garage and into the back bedroom, at this end we have an Ethernet Mount Box, rather than a box and face plate on the wall.

This cable was laid in April 2018 and has never been an issue up until the last month or two.

Speeds on this will randomly drop from what they should be (420/37) to less than 100, pings all over the place, slow loading websites etc. A quick reboot of the router and things are back up and running.

It only seems to be this Port that is affected which now rules out the Router itself. (I tested the other PC which directly connects to the router via another LAN and it was showing full, normal speeds 420/37)

I've now narrowed it down to the following;
  • It's either the LAN1 port (Switched to LAN3 for now)
  • Removed Old Powerline from the Router as its not longer needed on there.
  • The cable from the LAN 1 (Now LAN3) to the box that supplies the outside cable (Already swapped this though)
  • The cable from the box to the mount box. (The outside cable)
  • The connection/crimp of the cables in the boxes. (Mount Box was recently redone, so next port of call is to look at the other end!)
  • The cable from mount box upstairs to the switch (Already changed this too)
  • The switch itself

It's hard to try and figure this one out as it really is random as to when it happens. 18 days of it being fine before it decided to mess up again.

Plan of action
  • Swap the box that sits near the router that has the outside cable in, switch to a mount box the same as upstairs, this then forces me to recrimp/rewire it.
  • If it persists, when it happens again, try the cable upstairs from the mount to the switch directly into the PC and see what speeds are. If this fixes it, then dodgy switch?
  • If it still persists, look at removing the outside wiring and starting over with new wire.
Is there any logical explanation as to what could be causing this at all?
  • The router never shows the LAN connection as 100MBps it shows all LAN connections as 1GBPS, which for me rules out the wire to some extent?
  • A reboot of the router, or unplugging the ethernet from the router and putting it back in works fine too?
The switch is an 8 Port Netgear GS308 connected in the back bedroom (Cable from the mount box straight into this). It has the PC, SkyQ Box, Chromecast Ultra, TP Link Access Point, PS4, Samsung TV attached to it.

I'm out of other ideas at the moment? Can anyone else think of anything it could be? Or are the above steps covering everything?

Edit: Updated the switch information.
 
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maxbraketorque

Very Senior Member
My guess is that its a cable termination issue or something with the cable connectors on the cables or in the devices. Switching to LAN3 should at least eliminate the router as a possible culprit. If it comes back on LAN3, then it could be a host of possibilities, including the devices on the ethernet network. You mention a GS308 switch later in your thread, but I don't see an explanation of how/where its attached to your network.
 

Jbennett360

Regular Contributor
My guess is that its a cable termination issue or something with the cable connectors on the cables or in the devices. Switching to LAN3 should at least eliminate the router as a possible culprit. If it comes back on LAN3, then it could be a host of possibilities, including the devices on the ethernet network. You mention a GS308 switch later in your thread, but I don't see an explanation of how/where its attached to your network.
The GS308 switch is located in the back bedroom. It's a cable from the mount box in the bedroom to the switch, then off the switch there's PC, SkyQ Box, Chromecast Ultra, TP Link Access Point, PS4, Samsung TV attached to it.

I'm swayed to the faceplate near the router. The one in the back bedroom has recently been done and was a lot easier to do than a faceplate!

I think i'll look at taking the faceplate off, snipping an inch of the wire and then rewiring/punching into the new mount box I've bought and not bothering with the faceplate.

The last device to be added to the switch was the Chromecast. Everything else has been there from day one.
 

maxbraketorque

Very Senior Member
So the GS308 is the fan-out for all the devices at the end of the affected ethernet run? I have seen an issue where a bad termination will be ok for a short period and then cause issues, but I also wonder whether one of the devices in the back bedroom is causing the issue, either the switch or one of the attached devices. If the issue returns on LAN3, I'd try disconnecting the Chromecast without touching anything else.
 

Jbennett360

Regular Contributor
So the GS308 is the fan-out for all the devices at the end of the affected ethernet run? I have seen an issue where a bad termination will be ok for a short period and then cause issues, but I also wonder whether one of the devices in the back bedroom is causing the issue, either the switch or one of the attached devices. If the issue returns on LAN3, I'd try disconnecting the Chromecast without touching anything else.
Correct. The outside cable comes in and goes into the switch, off the switch we have all the above mentioned devices.

So what i'll do;
  • Carry one as I am on LAN3.
  • If it happens again, remove Chromecast and leave that disconnected
  • See if it happens after this.
The chromecast ethernet goes from the switch to the plug of the chromecast.

It does seem to happen after, or during me using Google Stadia via the Chromecast. Streaming games at 4K res ~20Gb per hour.
 
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Jbennett360

Regular Contributor
So the GS308 is the fan-out for all the devices at the end of the affected ethernet run? I have seen an issue where a bad termination will be ok for a short period and then cause issues, but I also wonder whether one of the devices in the back bedroom is causing the issue, either the switch or one of the attached devices. If the issue returns on LAN3, I'd try disconnecting the Chromecast without touching anything else.
So far so good. I did have an issue on Sunday with Stadia being laggy, could well be down to Stadia. As a precaution, i changed the ethernet cable from the Chromecast Plug to the switch (I have a feeling that was a dodgy cable for some reason!)

No glitches so far with Stadia.

Will see how it goes.

I was also trying to remember when the issues first started and im struggling to think, was thinking it could well be down to FW. I have a feeling everything was fine on Merlin 384.15, but, i can't be too certain!
 

maxbraketorque

Very Senior Member
So switching to LAN3 appears to have resolved the issue? But you also switch to a new ethernet cable on the Chromecast at the same time?
 

Jbennett360

Regular Contributor
So switching to LAN3 appears to have resolved the issue? But you also switch to a new ethernet cable on the Chromecast at the same time?
It's too early to judge as it's only been a few days. It took 3 weeks before for the issue to reoccur so it could still happen.

I swapped the ethernet cable on the chromecast purely because I was having a few issues with Stadia saying my connection was unstable or laggin (could have purely been down to the session, or server etc) but I've experienced less of these since the cable swap.

I'll keep an eye on it. I'm making notes everytime I've changed something or spot something that's not right
 

Jbennett360

Regular Contributor
So switching to LAN3 appears to have resolved the issue? But you also switch to a new ethernet cable on the Chromecast at the same time?
No issues as of yet.

Looks like it may have been LAN1 port!

Unless I've jinxed myself and it happens withing the next day or so!
 

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