[RT-AC68U] Not getting Gigabit with Realtek Lan

[thewan]

I have an RT-AC68U Rev. A2, running Advanced Tomato 3.3-138. I actually bought in early January, but only recently decided to upgrade the wiring in my house to gigabit. I noticed that 2 of my PCs, both using the integrated Realtek RTL 8168/8111 NIC, are stuck in 100mbps mode after changing my cables.

Now before you all blame bad cable/connections, I am using CAT6E cables. Also my family has PCs/Laptops/Macbooks with Intel, Qualcomm/Killer and Broadcom NICs in them, and they all work at 1.0gbps mode. And yes I tested all of them on the exact same cable that is used to connect to the PCs with the Realteks. I have tested them with iperf and can confirm that I can sustain gigabit speeds between the systems with the above NICs (~900mbps) so cable quality should be a non-issue.

I can't use Asus's Firmware or Merlin's since I have issues with WAN disconnections as was discussed here. Is it a firmware issue? I might try going back to Asus Firmware just to try it out, but since the WAN issue is not fixed, there is no point in doing so. I have tried numerous fw revisions till the latest ones and all of them disconnects the WAN after a day or so and refuse to reconnect back until I restart the router via the power button, soft restarting doesn't work. And no, none of the fixes suggested in the above thread work for me. Tomato has no issues with my WAN so this is obviously a fw issue not my ISP issue.

So the question is, can I do anything about this without buying a new router? Asus has not got back to me on either issues, so I gave up hope on asking for a replacement/refund if it is the router that is faulty. I doubt that both of the PCs Realtek NICs are faulty since they run fine in 100mbps mode. I also have no plans to replace those PCs as of this year.

Thanks.

 

[TonyH]

I have an RT-AC68U Rev. A2, running Advanced Tomato 3.3-138. I actually bought in early January, but only recently decided to upgrade the wiring in my house to gigabit. I noticed that 2 of my PCs, both using the integrated Realtek RTL 8168/8111 NIC, are stuck in 100mbps mode after changing my cables.

Running latest Realtek drivers? Checked advanced settings on the NIC property?

 

[thewan]

I was running drivers that was released in May, noticed today there was an update, so I updated to the latest one which was released in July. In advanced settings, I have disabled Energy Efficient Ethernet and Green Ethernet, the rest is left at default. Speed & Duplex is set to autonegotiation. There is no change, still stuck at 100mbps. I tried changing that setting to 1.0gbps full duplex but it didnt work either.

 

[doczenith1]

I recently purchased a Intel N3700 based mb with an integrated Realtek RTL8111GR and it is working fine for me. I also have an older AMD E-350 based mb with an integrated Realtek 8111E chip and it is also working just fine. I made no changes to the nic properties in Windows. The Intel is on Win 7 and the AMD on Win 10. Both are running the latest drivers downloaded from the Realtek website.

 

[sfx2000]

I noticed that 2 of my PCs, both using the integrated Realtek RTL 8168/8111 NIC, are stuck in 100mbps mode after changing my cables.

Realtek's are extremely sensitive to cable quality - been there... Both for Windows and Linux...

 

[thewan]

Realtek's are extremely sensitive to cable quality - been there... Both for Windows and Linux...

So it is still a cable issue. Can't do much if I already invested in wiring the whole house with them. I guess I'll live with it til I either decide to change my cables or buy a new PC with no Realtek NICs in them.

Thank you.

I recently purchased a Intel N3700 based mb with an integrated Realtek RTL8111GR and it is working fine for me. I also have an older AMD E-350 based mb with an integrated Realtek 8111E chip and it is also working just fine. I made no changes to the nic properties in Windows. The Intel is on Win 7 and the AMD on Win 10. Both are running the latest drivers downloaded from the Realtek website.

Thank you as well. I concluded, like the poster after you said together with what you said, that it is still a cable issue. Both of my PCs have 8111E, so I'll probably look to replace them if I decide to not replace the cables.

 

[wouterv]

Probably the cable it self is ok, but the termination is done in a poor way.
I suppose you run fixed cables to sockets and from the sockets you have patch cables to the client devices and the router.
For testing purpose, bring the problem PC closer to the router and use a shorter patch cable to see how that works. If that works well, the issue is with your cabling or termination.
Are the wire pairs (colors) connected according the rules in the terminations, how is the cable shield terminated?
Another suggestion may be to set the speed and mode fixed instead of auto negtotiate.

 

[thewan]

Probably the cable it self is ok, but the termination is done in a poor way.
I suppose you run fixed cables to sockets and from the sockets you have patch cables to the client devices and the router.
For testing purpose, bring the problem PC closer to the router and use a shorter patch cable to see how that works. If that works well, the issue is with your cabling or termination.
Are the wire pairs (colors) connected according the rules in the terminations, how is the cable shield terminated?
Another suggestion may be to set the speed and mode fixed instead of auto negtotiate.

You gave me an idea on how to check my cable. Instead of bringing the problematic PC to the router, I brought my laptop (Qualcomm Atheros Gigabit Lan) to the router end of the cable, plugged in the lan cable which is wired to the said PC. Gigabit was instantly negotiated between the two.

So with all of them using the exact same cable:

Laptop <-> Router = Gigabit
PC <-> Router = 100mbps
Laptop <-> PC = Gigabit

I really don't think its the cable now. Btw I did not use sockets for my wiring. I just run long cables directly from one end to the other. No shorter patch cables used.

 

[wouterv]

Speed & Duplex is set to autonegotiation

Try now to change the Speed and Duplex setting of the Realtek adapter, set it to 1 Gbps/Full duplex.
Autonegotiate is good as long as it works...different brands may negotiate in different ways with each other, with different results.
I have learned in professional applications to stay sure and set things fixed, bad thing is that you cannot set the Asus router end.

 

[thewan]

Try now to change the Speed and Duplex setting of the Realtek adapter, set it to 1 Gbps/Full duplex.
Autonegotiate is good as long as it works...different brands may negotiate in different ways with each other, with different results.
I have learned in professional applications to stay sure and set things fixed, bad thing is that you cannot set the Asus router end.

I tried changing that setting to 1.0gbps full duplex but it didnt work either.

I did mention that I tried that. I didnt work. I just tried again and it still doesn't work.

One thing to note, with the devices that successfully connect at gigabit, negotiation happens instantly, meaning Windows straightaway shows that I'm connected the moment I connect the cable. But on the problematic PCs, it looks like the Realtek NICs are failing to negotiate gigabit as it takes around 5-10 seconds before it finally connects at 100mbps.

 

[wouterv]

I suggest to replace the Realtek interface cards by e.g. Intel types.

 

[thewan]

I suggest to replace the Realtek interface cards by e.g. Intel types.

Thanks for the suggestion. I'll be changing to a new PC probably by the time Kaby Lake desktops CPUs arrive over here. It is very hard to find PCIE gigabit cards here, let alone Intel ones. And it's probably more worth it to wait a while and replace my PCs instead of importing them PCIE gigabit cards.

Once again thanks all for ur input and help, I don't think I can do much besides changing PCs, but if anyone has anymore ideas, feel free to add them here for me to try.

 

[L&LD]

http://www.newegg.com/Product/Product.aspx?Item=N82E16833114004

For $12, I think it would be worth importing one now. Kaby Lake will probably take up to a year before it is available 'everywhere', at reasonable prices.

 

[thewan]

http://www.newegg.com/Product/Product.aspx?Item=N82E16833114004

For $12, I think it would be worth importing one now. Kaby Lake will probably take up to a year before it is available 'everywhere', at reasonable prices.

Considering that I'm having bad experience with the built-in Realtek NIC, I seriously doubt I will be buying a PCI card with another Realtek chip on it . Thanks but no thanks. I can get those cards locally, the ones I can't get are those that are not based on Realtek.

 

[L&LD]

Considering that I'm having bad experience with the built-in Realtek NIC, I seriously doubt I will be buying a PCI card with another Realtek chip on it . Thanks but no thanks. I can get those cards locally, the ones I can't get are those that are not based on Realtek.

I don't think that the Realtek chip is the issue. It seems like your specific NIC's are.

For a few dollars and five minutes of your time, I think it is worth to pursue this myself. YMMV.

 

[thewan]

I don't think that the Realtek chip is the issue. It seems like your specific NIC's are.

For a few dollars and five minutes of your time, I think it is worth to pursue this myself. YMMV.

Noted, although I would prefer a PCIe card considering the slot positions on my motherboard. And unfortunately, I don't earn American Dollars so for me it is not "just a few dollars". I'm not gonna try something that may not work and end up with paper weight. Realtek just doesn't inspire confidence in me right now, I've had issues with all their products in the past.

 

[sfx2000]

So it is still a cable issue. Can't do much if I already invested in wiring the whole house with them. I guess I'll live with it til I either decide to change my cables or buy a new PC with no Realtek NICs in them.

Thank you.

You can try forcing the issue with the client side by manually setting the speed and duplex values in the advanced settings of the driver - so that might be an option to try...

 

[john9527]

How about putting in a low-cost un-managed Gb switch for your local devices, then go to the router? This has been used successfully to get around negotiation issues.

 

[L&LD]

Noted, although I would prefer a PCIe card considering the slot positions on my motherboard. And unfortunately, I don't earn American Dollars so for me it is not "just a few dollars". I'm not gonna try something that may not work and end up with paper weight. Realtek just doesn't inspire confidence in me right now, I've had issues with all their products in the past.

Do you really not have the option to return a product if not fit for purpose?

 

[sfx2000]

I don't think that the Realtek chip is the issue. It seems like your specific NIC's are.

For a few dollars and five minutes of your time, I think it is worth to pursue this myself. YMMV.

I spoke a bit earlier about realtek nics being somewhat sensitive to media quality - and this is true...

For OP's concern however - media quality is probably the biggest issue - and that is easy to test by running another cable temporarily and see what happens... a 50 foot loose cable is cheap...