File Transfer on RT-N66U Causes Poor Connection for Everything Else

[milkmandan]

I am about to throw this router out the window. If anyone could tell me what the heck is going on and if there is any solution, I would be eternally grateful.

Setup:
All cables are CAT6. Everything is Gigabit.

Computer A <------> RT-N66U <-------> RT-N56U (Acting in AP Mode) <------> Gigabit Switch <-------> Computer B

Problem:
When I try to transfer any file (preferably a large file ~1+GB), from Computer A to Computer B's Shared Folder, I get ABYSMAL speeds. Windows reports the copy moving at 11MB/s ~ 20MB/s.
I have several other services connected to the network, such as a TeamSpeak and Minecraft server, and during this copy period, players on my Minecraft Server get DC/ed and people in TeamSpeak report audio stuttering as if there is packet loss.

Also during this file transfer period, loading the administration page on the router (192.168.1.1, etc), is incredibly slow. Takes about 2 minutes to load any page. And as soon as I cancel the File Transfer, the page loads instantly.

In addition, I have Computer C connected to the RT-N56U, and I try a file copy from Computer C to Computer B, and I get awesome speeds, and no services are affected. So I know the problem is not with the switch or the RT-N56U in AP mode.
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However, as soon as I power cycle the RT-N66U, I try the copy over again, the speeds jump up to well over ~110MB/s. And no one is kicked from Minecraft and TS is working beautifully.

The problem will return after I leave the router on for an hour or so.

What is going on?

I've tried both of the newest firmwares on the ASUS Firmware page for this Router, and nothing has worked.

I am not sure if it is a heat issue? My room is usually anywhere from 75 to 85F. And the router isn't kept in any super enclosed space.

Something is bogging the router down whenever I try to transfer a file and only after it has been up for a little bit. I've updated my network adapter drivers as well.

 

[Fraoch]

It sounds like something is bogging down the CPU of the router or consuming too much memory. Access it by SSH and type in "top". See if your CPU is overloaded or your free memory is low.

If it is...there's not much you can do about it, but that would be the cause.

It shouldn't as LAN traffic should go through the LAN switch chip which is separate from the CPU, but that's what it sounds like for some reason.

Edit: wait a second, where's your Minecraft server running? Computer A, B or C? How are transfers from C to A? Does computer A show high CPU or I/O usage while transferring? Gigabit transfers can often saturate a hard drive speed connection (should be faster than 11 - 20 MB/s but still). You may also want to try a speed test like iperf between computers A and B and A and C. iperf does not depend on your hard drive so if you get near-gigabit tests with iperf, it may be your hard drive.

 

[milkmandan]

It sounds like something is bogging down the CPU of the router or consuming too much memory. Access it by SSH and type in "top". See if your CPU is overloaded or your free memory is low.

If it is...there's not much you can do about it, but that would be the cause.

It shouldn't as LAN traffic should go through the LAN switch chip which is separate from the CPU, but that's what it sounds like for some reason.

Edit: wait a second, where's your Minecraft server running? Computer A, B or C? How are transfers from C to A? Does computer A show high CPU or I/O usage while transferring? Gigabit transfers can often saturate a hard drive speed connection (should be faster than 11 - 20 MB/s but still). You may also want to try a speed test like iperf between computers A and B and A and C. iperf does not depend on your hard drive so if you get near-gigabit tests with iperf, it may be your hard drive.

Unfortunately, i dont have any custom firmware on it, I am using the Asus firmware and I don't think I can SSH into my router. Please let me know if I am wrong.

As such, I am unable to check if something is bogging down my CPU or if I am low on memory.

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Computer A <-> RT-N66U <-> RT-N56U (Acting in AP Mode) <-> Gigabit Switch <-> Computer B

Computer C is connected to the RT-N56U (Acting in AP Mode)
And Minecraft is running on Computer C.

Transfers from Computer C to A are the same as B to A and vice versa. A crawl at 11-20MB/s.
Computer A shows very low CPU usage while transferring. Pretty sure it is not my hard drive, as I've tried copying to and from an SSD and 10k rpm drive. Both copy at 11-20MB/s.

 

[CaptainSTX]

Break System Down

To find the bottle neck I suggest you break your system down and try and isolate the component bottle necking your set up

Test first with everything connected to your primary router. Rotate cables and LAN ports to see if anything improves.

Then try running from the primary router to the switch and see what happens.

Finally add in the AP. Try it both in front of the switch and then connected to a LAN port on the switch.

If necessary and you think the N66U is the problem try putting the 56 in its place and see if it makes any difference.

While this is a lot of work it is the most straight forward approach to find out where the problem is.

 

[milkmandan]

will do, i will try isolation.

Also i turned on Telnet, found the option in the admin setting page.

edit: problem never resolved, just replaced front end router with n56u and used n66u as AP mode. :\
going to wait several firmware version before trying again.