Fixed [RT-N66U] Integrated switch goes to 100 MB/s for no reasons.

[Nh3xus]

Hi,

First of all, I'm new on SNB

I've bought the RT-N66U a year ago, and I've been pretty happy with it until recently.

I'm running the official 3.0.0.4.376_3861 firmware from Asus.

For no reason, the integrated switch randomly loses the Gigabit duplex speed and fallback to the 100 BASE-T duplex.

I've forced the Gigabit duplex on the managed switch which the Asus is connected to, but no luck.

Any idea on how I can fix this ?

 

[netwrks]

Has anything changed between the two devices? New cable, or new fw on the managed switch side? Have you tried different ports, on the router, or managed switch side?

 

[Nh3xus]

No changes between the two devices (e.g no new firmware or anything).
No new cables either.

My house is fully wired with Cat6 cables and I've tested the whole wiring with a proper network tester device.

So I'm glad that the wiring of the house is out of the equation

I've not changed the ports on both devices like you suggested.

I will do that and report back if it pays off.

That being said, both devices are under warranty so RMA can be a thing if needed.

 

[netwrks]

Typically, 1000mb is auto-negotiated between two devices. 10 and 100mb are configured. Especially nowadays when most ports are 1000mb). On occasion, two devices will stop playing well together. (not auto-negotiating). It's more common between a router port and a modem port, and then it is recommenced to put an unmanaged gig switch between the two uncooperative devices, so that negotiation can be resolved (which is usually the case).. In your case, that seems redundant. Hard to say who the culprit is. Do you know if there is any new firmware for either device?

EDIT: Have you tried rebooting router or switch to see if that resolves the negotiation issue?

EDIT2: Any indication in the router logs of what is going on with port negotiaton?

 

[Nh3xus]

There's no new firmware available for the managed switch.

However there's a new official "Beta" firmware for the Asus router as we speak.

Rebooting both devices do the trick, but still don't lead me to any kind of conclusion regarding the issue I'm facing.

I've switched the wire from LAN 1 to LAN 2 on the Asus router.

I'll see if that is any better.

Regarding the logs, I've cleared them in order to actually export them when the connexion fails again.

 

[netwrks]

Perhaps the logs will reveal something..

 

[Nh3xus]

Yes, that's what I'm hoping too.

I don't think that the manageable switch is the culprit because the other devices don't have negotiation mismatch.

Having only one faulty port would be surprising.

If the connexion fails again, then I will swap the port on the managed switch.

 

[L&LD]

You might still want to test different cables as it might be the connectors, not the wires themselves that is the issue on one or both devices (their interaction).

Btw, it is connection, not connexion.

 

[Nh3xus]

I've swapped the cables already.

Please keep in mind that I've tested them with a proper RJ45 cable tester and did not find any fault regarding them.

I'm using the LAN2 port instead of the LAN1 port and so far, I've not encountered any kind of problem.

Stay tunned, I guess.

 

[CaptainSTX]

I've swapped the cables already.

Please keep in mind that I've tested them with a proper RJ45 cable tester and did not find any fault regarding them.

I'm using the LAN2 port instead of the LAN1 port and so far, I've not encountered any kind of problem.

Stay tunned, I guess.

Unless you have a fancy/expensive/professional cable tester most likely all you are testing is that all the pairs have continuity and they are pinned correctly at each end. Still worth testing, but it won't tell you what speeds the cable is capable of.

 

[Nh3xus]

all you are testing is that all the pairs have continuity

That's correct.

However, those cables are in service since November 2014 and my network performed at Gigabit speed on the LAN part just fine.

I know that expensive testers like the ones made by Fluke are what comes in your mind.

Everything is Cat6 certified and worked just fine until now.

A faulty cable would have been detected way sooner.

 

[L&LD]

As I mentioned already, I am suspicious of the connectors on the cables causing issues. Nothing that a human eye could see at first glance, but the interaction between the devices may push it over the edge.

But, if you have already swapped cables as you say...

 

[Nh3xus]

Ok, plugging the cable on the LAN2 port definitely did the trick.

Thanks guys.