ASUS RT-AC68U Strange N/AC Issues with WLAN to WLAN or LAN to WLAN PC traffic

[waldrondigital]

I've running the latest build of Merlin 378.50 (I factory reset and reconfigured), but my issue has nothing to do with Merlin. The router exhibited the same issue prior to the new build and I'm really perplexed as to what is going on.

When pinging between wireless computers that are N or AC, I'm experiencing extremely unstable and high pings. However when the client is pinging the Asus router, there are no problems and the latency and returns are normal. So basically Internet access on these system work without issue, it's just WLAN to WLAN and LAN to WLAN communications that are affected.

Examples -
Mac on 5GHz AC or 2.4GHz N pinging the Asus, normal, stable 1-3ms returns.
Windows PC on 5GHz AC or 2.4GHz N pinging the Asus, normal, stable 1-3ms returns.
Other systems pinging the Asus exhibit normal behavior.
G Devices seem unaffected and I can ping them with no latency.

My computer environment includes:
27" iMac
21.5" iMac
27" Dell XPS Win 8.1 (hardwired)
HP Envy laptop Win 8.1
Other N/G entertainment and security devices.

Now the strange behavior -
Pinging Mac to Mac, Mac to PC, or even telnetted into the Asus to any of these devices - I'll see strange latency and very high ping returns:

Telnetted into Asus pinging Windows 8 PC on 5GHz:
64 bytes from 192.168.192.139: seq=0 ttl=128 time=3.619 ms
64 bytes from 192.168.192.139: seq=1 ttl=128 time=125.455 ms
64 bytes from 192.168.192.139: seq=2 ttl=128 time=429.737 ms
64 bytes from 192.168.192.139: seq=3 ttl=128 time=61.138 ms
64 bytes from 192.168.192.139: seq=4 ttl=128 time=366.715 ms
64 bytes from 192.168.192.139: seq=5 ttl=128 time=587.801 ms
64 bytes from 192.168.192.139: seq=6 ttl=128 time=86.384 ms
64 bytes from 192.168.192.139: seq=7 ttl=128 time=441.884 ms
64 bytes from 192.168.192.139: seq=8 ttl=128 time=26.616 ms
64 bytes from 192.168.192.139: seq=9 ttl=128 time=541.831 ms
64 bytes from 192.168.192.139: seq=10 ttl=128 time=201.494 ms

Pinging Windows 8 connected via 2.4Ghz N from wired Windows 8 PC:
Reply from 192.168.192.139: bytes=32 time=1538ms TTL=128
Reply from 192.168.192.139: bytes=32 time=1ms TTL=128
Reply from 192.168.192.139: bytes=32 time=610ms TTL=128
Reply from 192.168.192.139: bytes=32 time=215ms TTL=128
Reply from 192.168.192.139: bytes=32 time=375ms TTL=128
Reply from 192.168.192.139: bytes=32 time=770ms TTL=128
Reply from 192.168.192.139: bytes=32 time=789ms TTL=128
Reply from 192.168.192.139: bytes=32 time=167ms TTL=128
Reply from 192.168.192.139: bytes=32 time=1ms TTL=128
Reply from 192.168.192.139: bytes=32 time=1ms TTL=128
Reply from 192.168.192.139: bytes=32 time=1ms TTL=128
Reply from 192.168.192.139: bytes=32 time=448ms TTL=128
Reply from 192.168.192.139: bytes=32 time=29ms TTL=128
Reply from 192.168.192.139: bytes=32 time=200ms TTL=128
Reply from 192.168.192.139: bytes=32 time=147ms TTL=128
Reply from 192.168.192.139: bytes=32 time=1ms TTL=128
Reply from 192.168.192.139: bytes=32 time=618ms TTL=128
Reply from 192.168.192.139: bytes=32 time=44ms TTL=128
Reply from 192.168.192.139: bytes=32 time=4ms TTL=128
Reply from 192.168.192.139: bytes=32 time=198ms TTL=128

Telnetted into Asus pinging Mac on 5GHz AC:
64 bytes from 192.168.192.110: seq=0 ttl=64 time=185.610 ms
64 bytes from 192.168.192.110: seq=1 ttl=64 time=1.303 ms
64 bytes from 192.168.192.110: seq=2 ttl=64 time=28.250 ms
64 bytes from 192.168.192.110: seq=3 ttl=64 time=256.864 ms
64 bytes from 192.168.192.110: seq=4 ttl=64 time=178.239 ms
64 bytes from 192.168.192.110: seq=5 ttl=64 time=99.503 ms
64 bytes from 192.168.192.110: seq=6 ttl=64 time=0.769 ms
64 bytes from 192.168.192.110: seq=7 ttl=64 time=34.992 ms
64 bytes from 192.168.192.110: seq=8 ttl=64 time=0.935 ms
64 bytes from 192.168.192.110: seq=9 ttl=64 time=93.409 ms
64 bytes from 192.168.192.110: seq=10 ttl=64 time=0.773 ms
64 bytes from 192.168.192.110: seq=11 ttl=64 time=242.496 ms
64 bytes from 192.168.192.110: seq=12 ttl=64 time=162.752 ms
64 bytes from 192.168.192.110: seq=13 ttl=64 time=0.883 ms

Typically any of these computers when pinging the Asus router no matter how they are connected, look like this, completely normal (in this example I'm pinging from a Windows 8 system on 2.4 GHz) and 5GHz looks identical for the most part:
Reply from 192.168.192.1: bytes=32 time=1ms TTL=64
Reply from 192.168.192.1: bytes=32 time=1ms TTL=64
Reply from 192.168.192.1: bytes=32 time=4ms TTL=64
Reply from 192.168.192.1: bytes=32 time=3ms TTL=64
Reply from 192.168.192.1: bytes=32 time<1ms TTL=64
Reply from 192.168.192.1: bytes=32 time=2ms TTL=64
Reply from 192.168.192.1: bytes=32 time=4ms TTL=64
Reply from 192.168.192.1: bytes=32 time=2ms TTL=64
Reply from 192.168.192.1: bytes=32 time=2ms TTL=64
Reply from 192.168.192.1: bytes=32 time=1ms TTL=64
Reply from 192.168.192.1: bytes=32 time<1ms TTL=64

Pinging latest generation Airport Express (used only for Airplay) which is connected to 2.4GHz from Asus, PC or Mac:
Reply from 192.168.192.2: bytes=32 time=4ms TTL=64
Reply from 192.168.192.2: bytes=32 time=2ms TTL=64
Reply from 192.168.192.2: bytes=32 time=3ms TTL=64
Reply from 192.168.192.2: bytes=32 time=3ms TTL=64
Reply from 192.168.192.2: bytes=32 time=4ms TTL=64
Reply from 192.168.192.2: bytes=32 time=3ms TTL=64
Reply from 192.168.192.2: bytes=32 time=2ms TTL=64
Reply from 192.168.192.2: bytes=32 time=2ms TTL=64
Reply from 192.168.192.2: bytes=32 time=3ms TTL=64

Pinging my Brother printer connected via G, from Windows (Mac looks same):
Reply from 192.168.192.20: bytes=32 time=2ms TTL=255
Reply from 192.168.192.20: bytes=32 time=2ms TTL=255
Reply from 192.168.192.20: bytes=32 time=2ms TTL=255
Reply from 192.168.192.20: bytes=32 time=2ms TTL=255
Reply from 192.168.192.20: bytes=32 time=2ms TTL=255
Reply from 192.168.192.20: bytes=32 time=6ms TTL=255
Reply from 192.168.192.20: bytes=32 time=3ms TTL=255
Reply from 192.168.192.20: bytes=32 time=3ms TTL=255
Reply from 192.168.192.20: bytes=32 time=2ms TTL=255
Reply from 192.168.192.20: bytes=32 time=2ms TTL=255

Oddly enough my Apple TVs connected to either 5GHz or 2.4GHz are fine, pings return normally, and these are N devices. I also have lots of G devices (Foscam cameras, Nest thermostats, etc.), and none of them have any of these issues.

I could understand if the client had crappy pings in both directions, but I'm perplexed that client initiated router/Internet communications are fine when router/WLAN/LAN initiated to WLAN-based PC/Mac traffic is affected.

THROWING MY HANDS UP!

 

[waldrondigital]

I was able to get the pings below 100ms by changing my DTIM to 1 in the 5GHz band and my Beacon Interval to 100. But the symptoms are the same as above, but with better pings.

Here I am pinging my Mac on 5GHz from my PC that's hardwired:
Reply from 192.168.192.230: bytes=32 time=73ms TTL=64
Reply from 192.168.192.230: bytes=32 time=90ms TTL=64
Reply from 192.168.192.230: bytes=32 time=106ms TTL=64
Reply from 192.168.192.230: bytes=32 time=10ms TTL=64
Reply from 192.168.192.230: bytes=32 time=14ms TTL=64
Reply from 192.168.192.230: bytes=32 time=21ms TTL=64
Reply from 192.168.192.230: bytes=32 time=32ms TTL=64
Reply from 192.168.192.230: bytes=32 time=40ms TTL=64
Reply from 192.168.192.230: bytes=32 time=48ms TTL=64
Reply from 192.168.192.230: bytes=32 time=56ms TTL=64
Reply from 192.168.192.230: bytes=32 time=65ms TTL=64

Another observation:

If I keep steady traffic going on the Mac, like AirPlay streaming from it... the connection becomes 100% solid:
Reply from 192.168.192.230: bytes=32 time=2ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=2ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=2ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time<1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=2ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=2ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64
Reply from 192.168.192.230: bytes=32 time=1ms TTL=64

Pinging from Asus router, same Mac, with AirPlay going:
ASUSWRT-Merlin RT-AC68U_3.0.0.4 Sat Feb 7 01:44:50 UTC 2015
admin@RT-AC68U-D430:/tmp/home/root# ping 192.168.192.230
PING 192.168.192.230 (192.168.192.230): 56 data bytes
64 bytes from 192.168.192.230: seq=0 ttl=64 time=1.158 ms
64 bytes from 192.168.192.230: seq=1 ttl=64 time=0.702 ms
64 bytes from 192.168.192.230: seq=2 ttl=64 time=0.806 ms
64 bytes from 192.168.192.230: seq=3 ttl=64 time=0.788 ms
64 bytes from 192.168.192.230: seq=4 ttl=64 time=0.854 ms
64 bytes from 192.168.192.230: seq=5 ttl=64 time=0.726 ms
64 bytes from 192.168.192.230: seq=6 ttl=64 time=0.740 ms
64 bytes from 192.168.192.230: seq=7 ttl=64 time=0.886 ms
64 bytes from 192.168.192.230: seq=8 ttl=64 time=0.871 ms
64 bytes from 192.168.192.230: seq=9 ttl=64 time=0.910 ms
64 bytes from 192.168.192.230: seq=10 ttl=64 time=0.913 ms
64 bytes from 192.168.192.230: seq=11 ttl=64 time=0.790 ms


So I'm guessing it's something with power saving and ICMP traffic? Ugh.

 

[RMerlin]

I know Apple are doing a lot of stupid things in regards to wireless power management in Yosemite and iOS8, so if your issues mostly show when one of the two endpoints involves a Mac, that would be why. They are being overly aggressive with power management, which leads to latency issues.

 

[waldrondigital]

Thanks Merlin. Keep up the great work on the firmware... it's the best.