AC68U really slow internet using wireless, normal on ethernet

[Martin Mrvka]

Hi.

I'm using a AC68U in AP mode with latest stock firmware 3.0.0.4.378_4376 and I'm investigating a weird problem with slow internet connectivity for wireless clients only.

My wired setup is:

 AC68U --- CableModem --- Internet
 |  |            |
 |  HTPC         Debian Server
 TV

This means, the TV and the HTPC which are using ethernet on the AC68U don't have any problems AND also, when wireless clients access resources on the Debian Server (or the webinterface of the AC68U) there are no issues. Only for wireless clients accessing the internet using TCP. ICMP pings are OK.

And the real strange thing is, when sshing into the AC68U and doing something like "wget http://orf.at" on the commandline, this restores the speed for wireless clients back to normal for a couple of hours.

Just as if the AC68U goes into a sleep mode which is only interrupted when initating a TCP connection from the router itself.

There are no iptables rules or additional routes. AC68U has a static IP, clients get a dynamic on from the DHCP running on the cable modem.

Does anybody have any ideas what may cause the problem or how it can be nailed down? For sure I already tried Merlins build but had the same troubles. Not sure if the is related to some traffic shaping. I might try tomato or dd-wrt.

Many thanks,
Martin

 

[john9527]

On the Wireless/Professional tab
- try setting Enable WMM APSD to Disable for the band you are using (is it 2.4 or 5GHz?)

 

[Martin Mrvka]

Thanks - I've activated both bands and now disabled the WMM APSD for both.

However, I don't understand that I'm able to access my server without any problems, while external ones are not working. The SNAT is done on the CableModem, from the AC68U point of view it's just a different destination for the IP packet.

 

[Martin Mrvka]

Well, it didn't help... thanks anyway.

Additional, after being not at home for two days the wireless network got completely unresponsive (unable to authenticate). After a reboot of the AC68U everything was back to normal.

I'm going to try latest Merlin now, but I can't believe that this router is such a crap.