WiFi Stability Problem (RT-AC68U)

[Eric Sirianni]

I'm having WiFi connection stability problems with a newly purchased RT-AC68U. The problem occurs using both the latest stock ASUS Firmware and Merlin Firmware.

The basic problem is that wireless devices (Android Phone and iPhone) on the 2.4GHz band show strong WiFi signal, but are unable to actually connect to any network endpoints (WAN or LAN). In Android, this manifests itself with the exclamation point (!) annotation on the WiFi icon. When this occurs, disabling and re-enabling the WiFi on the phone solves the issue. This problem occurs sporadically (once or twice a day).

The upstream internet connection is from an AT&T Uverse gateway device. This problem did *not* occur with the exact same network setup with my old Linksys router. I also was using a ASUS RC-ACRH13 as an Access Point (wired). When I swapped that out for the RT-AC68U as the main router, I also don't experience the WiFi connection issue. This indicates to me that it is not a WiFi interference issue but some other problem with the RT-AC68U.

I have seen some posts on this forum in the past with very similar symptoms. Most notably: https://www.snbforums.com/threads/u...u-forced-to-reconnect-wireless-clients.22833/

I've gone through all the standard troubleshooting steps (factory reset, changed the wifi "mode", uses WiFi analyzer and picked the best channel, etc.) but the problem still persists. There are no logs on the router that show any errors when the problem occurs.

 

[L&LD]

Is your RT-AC68U still using the old SSID's? Did you 'forget' the networks on your client devices and then re-associate them to your new network? After flashing the firmware you want to use, did you reset the router followed by a minimal and manual install to secure the router and connect to the internet?

Did you disable network monitoring? Look for that setting in Administration on the Settings tab. Leave both boxes unchecked.

https://www.snbforums.com/threads/stubby-installer-asuswrt-merlin.49469/page-53#post-466844

https://www.snbforums.com/threads/n...l-and-manual-configuration.27115/#post-205573

https://www.snbforums.com/threads/rt-ac66u-slow-wan-to-lan.12973/page-3#post-269410

 

[Eric Sirianni]

Thanks for the reply and the links. I have attempted a "minimal setup" (leaving the default settings for everything) but I have not explicitly disabled those options as mentioned in the threads you linked. I will give that a try and report back.

I do not think that I 'forgot' the networks on my client devices, so I will try that. I did do a factory reset when reinstalling different firmwares (using the WebUI and the physical reset button). I have not changed the network monitoring from the default setting. I will try disabling it as well.

 

[Eric Sirianni]

I followed the steps above and re-initialized everything from scratch also with a brand new SSID. The problem still occurs. I'm guessing it's possibly related to a power saving feature on the phone since it seems to occur when waking the phone up from sleep. The only thing I see in the logs is a bunch of "WLCEVENTD Disassoc" messages around the time that the connectivity issue was occurring. Again, when the problem occurs, the wifi signal strength shows 4 bars, however there is no LAN or WAN connectivity on the device (loading 192.168.1.1 or fast.com in Chrome times out).

The mac address of my Samsung GS7 is 4C:66:41:2E:45:A7.

Feb 18 17:02:25 kernel: nf_conntrack_rtsp v0.6.21 loading
Feb 18 17:02:25 kernel: nf_nat_rtsp v0.6.21 loading
Feb 18 17:02:25 rc_service: ntp 378:notify_rc restart_diskmon
Feb 18 17:02:25 rc_service: waitting "start_firewall" via udhcpc ...
Feb 18 17:02:25 disk_monitor: Finish
Feb 18 17:02:25 miniupnpd[524]: version 1.9 started
Feb 18 17:02:25 miniupnpd[524]: HTTP listening on port 48926
Feb 18 17:02:25 miniupnpd[524]: Listening for NAT-PMP/PCP traffic on port 5351
Feb 18 17:02:25 rc_service: udhcpc 361:notify_rc start_upnp
Feb 18 17:02:25 rc_service: waitting "stop_upnp" via udhcpc ...
Feb 18 17:02:25 miniupnpd[524]: shutting down MiniUPnPd
Feb 18 17:02:26 disk monitor: be idle
Feb 18 17:02:27 miniupnpd[528]: version 1.9 started
Feb 18 17:02:27 miniupnpd[528]: HTTP listening on port 42897
Feb 18 17:02:27 miniupnpd[528]: Listening for NAT-PMP/PCP traffic on port 5351
Feb 18 17:02:27 dhcp client: bound 75.60.241.164 via 75.60.240.1 during 600 seconds.
Feb 18 17:03:16 crond[219]: time disparity of 417178 minutes detected
Feb 18 17:03:16 WLCEVENTD: eth1: Assoc 5C:51:4F:F4:F6:73
Feb 18 17:05:15 WLCEVENTD: eth1: Assoc 4C:66:41:2E:45:A7
Feb 18 17:05:40 WLCEVENTD: eth1: Disassoc 4C:66:41:2E:45:A7
Feb 18 17:05:40 WLCEVENTD: eth1: Disassoc 4C:66:41:2E:45:A7
Feb 18 17:05:40 WLCEVENTD: eth2: Assoc 4C:66:41:2E:45:A7
Feb 18 17:09:20 WLCEVENTD: eth2: Disassoc 4C:66:41:2E:45:A7
Feb 18 17:11:00 WLCEVENTD: eth2: Assoc 4C:66:41:2E:45:A7
Feb 18 17:11:55 WLCEVENTD: eth2: Disassoc 4C:66:41:2E:45:A7
Feb 18 17:14:54 WLCEVENTD: eth1: Assoc 84:D6:D0:9C:58:E2
Feb 18 17:15:19 WLCEVENTD: eth2: Assoc 4C:66:41:2E:45:A7
Feb 18 17:16:54 rc_service: cfg_server 957:notify_rc restart_wireless
Feb 18 17:17:04 WLCEVENTD: eth2: ReAssoc 4C:66:41:2E:45:A7
Feb 18 17:17:08 WLCEVENTD: eth1: Assoc 5C:51:4F:F4:F6:73
Feb 18 17:17:08 WLCEVENTD: eth1: Assoc 84:D6:D0:9C:58:E2
Feb 18 18:02:42 WLCEVENTD: eth2: Assoc 80:82:23:23:F4:13
Feb 18 18:03:19 WLCEVENTD: eth2: Assoc 80:82:23:23:F4:13
Feb 18 19:01:42 WLCEVENTD: eth1: Assoc 80:82:23:23:F4:13
Feb 18 19:02:01 WLCEVENTD: eth1: Disassoc 80:82:23:23:F4:13
Feb 18 19:02:01 WLCEVENTD: eth2: Assoc 80:82:23:23:F4:13
Feb 18 20:11:42 WLCEVENTD: eth1: Assoc 80:82:23:23:F4:13
Feb 18 20:15:20 WLCEVENTD: eth1: Disassoc 80:82:23:23:F4:13
Feb 18 20:15:20 WLCEVENTD: eth2: Assoc 80:82:23:23:F4:13
Feb 18 20:51:01 WLCEVENTD: eth1: Assoc 4C:66:41:2E:45:A7
Feb 18 21:09:55 WLCEVENTD: eth1: ReAssoc 4C:66:41:2E:45:A7
Feb 18 21:09:55 WLCEVENTD: eth1: Disassoc 4C:66:41:2E:45:A7
Feb 18 21:10:02 WLCEVENTD: eth1: Assoc 4C:66:41:2E:45:A7
Feb 18 21:13:05 WLCEVENTD: eth1: Assoc 4C:66:41:2E:45:A7
Feb 18 21:15:45 WLCEVENTD: eth1: Assoc 4C:66:41:2E:45:A7
Feb 18 21:17:15 WLCEVENTD: eth1: ReAssoc 4C:66:41:2E:45:A7
Feb 18 21:17:15 WLCEVENTD: eth1: Disassoc 4C:66:41:2E:45:A7
Feb 18 21:17:18 WLCEVENTD: eth1: Assoc 4C:66:41:2E:45:A7
Feb 18 21:19:53 WLCEVENTD: eth2: Assoc 4C:66:41:2E:45:A7
Feb 18 21:32:47 WLCEVENTD: eth2: Disassoc 4C:66:41:2E:45:A7
Feb 18 21:32:51 WLCEVENTD: eth1: Assoc 4C:66:41:2E:45:A7
Feb 18 21:32:51 WLCEVENTD: eth2: Disassoc 4C:66:41:2E:45:A7
Feb 18 21:37:47 WLCEVENTD: eth1: Assoc 5C:51:4F:F4:F6:73

Here is the wifi log at the same time (for the 2.4GHz band)

SSID: "sirianni"
RSSI: 0 dBm    SNR: 0 dB    noise: -88 dBm    Channel: 6
BSSID: 40:B0:76:20:3B:A0    Capability: ESS ShortPre ShortSlot
Supported Rates: [ 1(b) 2(b) 5.5(b) 6 9 11(b) 12 18 24 36 48 54 ]
VHT Capable:
   Chanspec: 2.4GHz channel 6 20MHz (0x1006)
   Primary channel: 6
   HT Capabilities:
   Supported MCS : [ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 ]
   VHT Capabilities:
   Supported VHT (tx) Rates:
       NSS: 1 MCS: 0-9
       NSS: 2 MCS: 0-9
       NSS: 3 MCS: 0-9
   Supported VHT (rx) Rates:
       NSS: 1 MCS: 0-9
       NSS: 2 MCS: 0-9
       NSS: 3 MCS: 0-9

Interference Level: Acceptable
Mode    : AP Only

Stations List                           
----------------------------------------
idx MAC               Associated Authorized    RSSI PSM SGI STBC Tx rate Rx rate Connect Time
   5C:51:4F:F4:F6:73 Yes        Yes         -38dBm No  Yes Yes   144.4M    6.5M 00:01:19
   4C:66:41:2E:45:A7 Yes        Yes         -43dBm No  Yes Yes   192.5M     24M 00:06:16
   84:D6:D0:9C:58:E2 Yes        Yes         -55dBm No  Yes Yes   144.4M  144.4M 04:21:59

 

[ColinTaylor]

Have you tried:

In newer routers, if you experience wireless stability issues then it's recommended that you disable the following options:

• MU-MIMO (some hardware revisions have non-functional/unreliable implementations)
• Airtime Fairness (causes connectivity issues for various devices, including wireless printers)
• Universal Beamforming (non-standard, might cause compatibility issues with some clients)

 

[Eric Sirianni]

Have you tried:

Yes, I have tried disabling those based on this thread: https://www.snbforums.com/threads/asus-rt-ac88u-drops-homekit-devices-wlceventd.54482/#post-466552

Since it seems related to some sort of sleep/power saving feature on the phone are there any WiFi settings related to that which I should experiment with? Again, this does not occur with my old Linksys wifi router or a new Asus RT-ACHR13 wifi router so the Phone is not the issue.

 

[ColinTaylor]

The only power related option I'm aware of is at Wireless > Professional > Enable WMM APSD. You could try disabling that.

 

[Eric Sirianni]

Wireless > Professional > Enable WMM APSD.

Thanks. I will give that a try when I get home, but I am not optimistic

This thread seems to point to similar issues with power saving https://www.snbforums.com/threads/iphone-drops-wifi-on-lock-screen-and-slow-association.44602/

I also tried downgrading to the older firmware (3.0.0.4.384.32799) last night since I don't seem to recall having these issues during the first few days when I had the router using the factory-installed firmware (before upgrading to the latest stock asus firmware). Will see if that helps the stability...

 

[Ronald Schwerer]

Since it seems related to some sort of sleep/power saving feature on the phone are there any WiFi settings related to that which I should experiment with? Again, this does not occur with my old Linksys wifi router or a new Asus RT-ACHR13 wifi router so the Phone is not the issue.

I know you think it is the router (since it is what changed) but I had a similar issue with my Android phone (an old Nexus 5). I found a phone setting under Wi-Fi/Advanced (look on the top right side for additional settings)
and changed "Keep Wi-Fi on during sleep" to "Always". That solved my problem.

 

[Eric Sirianni]

I know you think it is the router (since it is what changed) but I had a similar issue with my Android phone (an old Nexus 5). I found a phone setting under Wi-Fi/Advanced (look on the top right side for additional settings)
and changed "Keep Wi-Fi on during sleep" to "Always". That solved my problem.

Thanks Ronald. I am aware of that setting and I already have it set to Always.

 

[Max Pixel]

Eric, did you ever resolve the issue? I'm having very aggressive
WiFi connectivity issues on AC3100@384.9Merlin, even with all of the recommended settings that you also seem to have gone through to no avail. I even disabled the suggested culprits on 5Ghz, and am seeing the problem equally on 5 & 2.4.

I'm considering downgrading to 380 firmware as a solution.