AC-86U intermittent drops and lag

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Peterock

New Around Here
Hello,

I have been trying for over a year to fix my intermittent disconnects and lag. I still cannot determine what is the cause of the problem but maybe some of the generous and knowledgeable folk around here can offer some advice? It would be much appreciated.

I currently have cox for ISP, an mb8600 modem, and an ac86u router with one unmanaged TPlink switch after that. I am currently running merlin 386.2, but it was happening with merlin 384.19, and also on asus 3.0.0.4.386.40451.

When I run ping -t www.google.com I get this:

Reply from 172.217.4.164: bytes=32 time=16ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Reply from 172.217.4.164: bytes=32 time=22ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=13ms TTL=118
Reply from 172.217.4.164: bytes=32 time=22ms TTL=118
Reply from 68.96.192.131: Destination host unreachable.
Reply from 172.217.4.164: bytes=32 time=2542ms TTL=118
Reply from 172.217.4.164: bytes=32 time=18ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=13ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 68.96.192.131: Destination host unreachable.
Reply from 172.217.4.164: bytes=32 time=1327ms TTL=118
Reply from 172.217.4.164: bytes=32 time=21ms TTL=118
Reply from 172.217.4.164: bytes=32 time=132ms TTL=118
Reply from 172.217.4.164: bytes=32 time=139ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=18ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=2241ms TTL=118
Reply from 172.217.4.164: bytes=32 time=13ms TTL=118
Reply from 172.217.4.164: bytes=32 time=34ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Reply from 172.217.4.164: bytes=32 time=21ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Request timed out.
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=16ms TTL=118
Reply from 172.217.4.164: bytes=32 time=18ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Reply from 172.217.4.164: bytes=32 time=24ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=20ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Reply from 172.217.4.164: bytes=32 time=18ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=18ms TTL=118
Reply from 172.217.4.164: bytes=32 time=32ms TTL=118
Reply from 172.217.4.164: bytes=32 time=13ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Reply from 68.96.192.131: Destination host unreachable.
Reply from 68.96.192.131: Destination host unreachable.
Reply from 68.96.192.131: Destination host unreachable.
Reply from 68.96.192.131: Destination host unreachable.
Reply from 172.217.4.164: bytes=32 time=1258ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=12ms TTL=118
Reply from 172.217.4.164: bytes=32 time=16ms TTL=118
Reply from 172.217.4.164: bytes=32 time=16ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=11ms TTL=118
Reply from 172.217.4.164: bytes=32 time=17ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=18ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=16ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=2472ms TTL=118
Reply from 172.217.4.164: bytes=32 time=13ms TTL=118
Reply from 172.217.4.164: bytes=32 time=13ms TTL=118
Reply from 172.217.4.164: bytes=32 time=19ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 172.217.4.164: bytes=32 time=16ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=13ms TTL=118
Reply from 172.217.4.164: bytes=32 time=13ms TTL=118
Reply from 172.217.4.164: bytes=32 time=16ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=18ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=18ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=14ms TTL=118
Reply from 172.217.4.164: bytes=32 time=15ms TTL=118
Reply from 68.96.192.131: Destination host unreachable.
Reply from 68.96.192.131: Destination host unreachable.
Reply from 68.96.192.131: Destination host unreachable.
Reply from 68.96.192.131: Destination host unreachable.
Reply from 68.96.192.131: Destination host unreachable.
Reply from 172.217.4.164: bytes=32 time=1641ms TTL=118
Reply from 172.217.4.164: bytes=32 time=16ms TTL=118
Reply from 172.217.4.164: bytes=32 time=13ms TTL=118

This happens on both hardwire and wifi connections. If I reboot my network hardware, it goes away maybe an hour or two and then returns again. What kind of diagnostics can I do to determine the problem? I called my ISP for tech support several times and had different levels of technicians come out over 10 times and was told each time that its not on their side. Asus tech support is not very helpful and I replaced my modem as well. I am kind of at a loss. Any help would be greatly appreciated! Thanks!
 
Last edited:

wouterv

Very Senior Member
What device is 68.96.192.131 ?
Anyhow the ~14 ms time seems rather long.
You should test it in further steps: connect the computer directly to the modem and do the ping, connect the computer directly to the router and do the ping, compare the results.
What more is connected to the router and what does the router status show for CPU and memory usage?
 

Peterock

New Around Here
Thank you for the reply!

That IP is my automatic IP from the ISP (but I changed a few numbers for security purposes). I will try to do the direct to modem and router test today.

The other things I have plugged in are 7 rokus (5 hardwire, 2 wifi) but only 2-3 are being used simultaneously, 2 ipads thru wifi (usually just one being used at a time), 2 smartphones, and a laptop (sometimes hard wired, sometimes wifi)

My cpu usage for core 1 and 2 currently is ranging from 0-10%

Memory is 339MB used of 522MB for 66% and that holds pretty steady. I do remember that being in the 90%'s with asus' firmware
 
Last edited:

Peterock

New Around Here
When I do a tracert <ip address> it usually fails on the 9th or 10th hop and says my wan IP - destination host unreachable
 

Tech9

Part of the Furniture
Just continuously ping Google from the modem and from the router. Look for latency spikes and compare.
 

bbunge

Part of the Furniture
The AC86U is usually a pretty steady beast. First thing I would do is replace the Ethernet cable between the router and the modem. CAT5 or better. If you have never done a hard factory reset of the router when switching between versions do so: https://www.asus.com/support/FAQ/1039078 Then do a minimal config and do not use saved settings. Use Dual Band Smart Connect, 2.4 GHz @ 20 MHz in Channel 1, 6 or 11, 5 GHZ @ 80 MHz on Channel 36 or 149. I recommend no add ons or QOS/AiProtect until you see if things are working better or not. To start use the ISP DNS servers. Get the basics working then start adding stuff. Oh, after resetting and a min config do a power off of the router for a few seconds.
 

Peterock

New Around Here
@Tech9 I will def try to see if it is happening straight off the modem, thank you

@bbunge thank you for the advice, however I have done all these things and no change. I use all cat6. My problems disappear temporarily when I do a reset, reboot, fresh reinstall
 

Peterock

New Around Here
before a reset... i plugged directly into the router with a brand new cat6 patch cable and am still getting destination host unreachable every 10-20 seconds with high MS returns. going to try a direct to modem cable reset tomorrow before my kids wake up otherwise there are tears if the internet is completely down. i have to wait a few hours after the reset because these lag spikes and disconnects set in after a little while
 

Peterock

New Around Here
by the way.... my ping tests do not report the destination host unreachable as packet loss... which i dont understand
 

Tech9

Part of the Furniture
ISPs have multiple servers and connections and the path to the same destination may not be always the same. Could you post the results of a simple ping to Google from the modem and from the router? Take a look at modem stats also, must be DOCSIS Events page or similar in modem's UI.
 

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