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RT-AC88U Drops/Flakey 5Ghz when set as AiMesh Node

Discussion in 'ASUS AC Routers & Adapters' started by JDB, Dec 8, 2018 at 3:51 PM.

  1. JDB

    JDB Very Senior Member

    Aug 28, 2016
    Hi All,

    So I've been running AiMesh with a pair of AC5300 (one as AP/AiMesh Router and the other as a node) for about 3 months now, and it's great.
    I recently added an AC88U in as a second node, see this thread for a bit more background on why/my architecture (also see my signature for my setup info) - https://www.snbforums.com/threads/my-new-rt-ac86u-and-some-qs-issues.50058/

    It's been running OK for a couple of days, but then yesterday I noticed my iPhone WiFi was not full strength despite having been sat 5 ft from the 88U for 30 mins, so I looked into what was going on.
    It was no long broadcasting 5Ghz at all, despite having the LED on, now I had just mounted it on the wall properly (was wedged on top of the TV for a couple of days before I committed to it's location) and when doing so I had knocked the WiFi On/Off button, so I gave it the benefit of the doubt that maybe something had gone fooey because of that. Cold booted it, 5Ghz came back for a few mins, then dropped again.

    It's worth noting that prior to being a Node, this was my main router (running Merlin) giving me rock solid 5Ghz only a few days ago. Since then was to flashed to the latest stock f/w, reset to factory and setup as a node.

    So at first I was thinking it was overheating, but given its only 18C in the room it's in and mounted to a cold brick wall I discounted that pretty quickly.

    Decided to factory reset again, re-add as a node, and hey - it's working again! Still I'm hoping it just wasn't happy with the fact I'd turned it's WiFi off and on and maybe something in the NVRAM was set wrong as a result and persisting over a reboot.

    So next day (today), this time my phone is dropping on and off the WiFi (sat in the same spot). Run some continuous WiFi scans and can see the 5Ghz is again playing up. It's going up and down, hopping channels and all sorts. So I reboot it, comes back doing the same thing. It was also clear the AiMesh was trying to roam the phone to the 88U and sometimes the BSSID was not there (or maybe not on the channel it was supposed to be), hence the phone would drop WiFi.
    So now I decided to reboot the AP/Router and the other Node, so all AiMesh devices have been cycled, and hey, after that everything is good again!

    So I'm thinking the problem is maybe the master AP/Router is telling the node to do these 5Ghz gymnastics.

    In the couple of days good running I had, I did a bunch of tests walking around monitoring signal and checking roaming handover speeds etc. I noted that one time I did it, the 88U was using the 5Ghz upper channel and the next day it had switched to the lower channel (in both cases was correctly sharing the channel of the AP/Router, obviously the 5300 has 2x 5Ghz radios). I didn't think much of it, just figured it would use which ever it saw was least congested and so occasionally would swap between upper and lower. Maybe it's this choice of 2x 5Ghz channels that is getting it all upset sometimes?

    Per signature, I have not updated the fw to the vary lasted versions just released due to known issues with 5300 and the 2nd 5Ghz band being disabled.

    I know there are various threads about AiMesh and it breaking with 3+ nodes and also about the 88U dropping 5Ghz when in normal router mode (thought I doubt the latter one is relevant to my issue), so hoping maybe someone somewhere has experienced similar and got an idea of what's happening. All the threads I've read so far haven't drawn any solid conclusions yet.

    If you've got here, thanks for reading, I know it's long, but wanted to share all the facts!

    Last edited: Dec 8, 2018 at 4:21 PM
  2. JDB

    JDB Very Senior Member

    Aug 28, 2016
    @Krusty tagging you as although your issues aren't exactly the same, they are as close as I can find!
    @HuskyHerder tagging you as you also have a large AiMesh so might have insights!

    Worth noting, all 3 of us have HomeKit and a significant number of smart devices by the sounds of it.

    It's not mentioned in my signature, but I run an Apple Time Capsule 3TB as a 2.4Ghz only AP as a separate SSID to the AiMesh, it has attached to it the various older and wireless b/g only devices, so my AiMesh 2.4Ghz has primarily newer wireless N compatible devices only.
    Reasons are I know mixing old with new doesn't do the router/network any favours with efficiency, hence the existence of options like Airtime Fairness (which many people have to disable inc myself for some devices to work).
  3. Krusty

    Krusty Occasional Visitor

    Nov 24, 2018
    Hey JDB... I should probably have mentioned that I am running with 3 different SSIDs for 5/5/2.4 and no smart connect... sounds like that is another variable you may have.

    Note also that it is a router + 3 nodes that breaks for me, not router + 2 nodes... though in all fairness as per other thread I do have occasional problems that can be solved by taking 2.4Ghz interface down on the main router even with two - my suspicion is that the whole issue may be dependent on the relative placement of the routers for Wifi between each other (even though I'm using wired backhaul).

    I'm gonna try to re-add the 3rd node today
    HuskyHerder and JDB like this.
  4. HuskyHerder

    HuskyHerder Senior Member

    May 12, 2017
    As for me, and my setup, see signature. Thanks for the assistance @JDB

    2.4G channel Devices:

    1, ecobee
    2, Apple Watches, they never connect on 5G even with the ways on the net to force them. Thats not an issue so its on the back burner.
    1, Phillips Hue Hub with 37 bulbs
    5, iDevices smart switches * wall wart kind
    1, iDevice Wall switch.

    HomeKit setup:
    4 Apple TVs as hubs, 1 ATV4K as primary and 3 ATV 4 (non k) in standby mode.

    Phillips Hue:
    The single most relevant thing for me as to keeping my hue bulbs working was to change the control channel between the Hue Hub and the Bulbs. It was set at 20 and I force changed it to 25. I did some hunting at the Phillips forums and this topic came up after finding it. It has helped immensely. https://www.metageek.com/training/resources/zigbee-wifi-coexistence.html

    Routers changes:

    No Smart connect with the 2.4 channels and the 5G channels. Smart connect was only used in the older 3 channel version for the 5300 just between the 2, 5G channels. Now it's not used at all. :( Thats another issue.

    * Everything is default unless mentioned below.

    Using WPA2 with very strong encryption. *Including a few special characters which both Apple and ASUS hate at times.
    2.4G RSSI: -48 * My specific setting not for everyone.
    Airtime Fairness: - disable
    Explicit Beam Forming: - disable
    Universal Beam Forming: - disable
    Power level: Balanced


    Also make sure "Enable IGMP Snooping" is disabled. I experienced huge issues if it's enabled, flaky response, no response, severe lag etc.
    I also saw a post to change the Modulation Scheme from 11 to 9 if the Router supports it. I also experienced very poor performance with this. It took all of 10 minutes and I switched it back to 11.

    Special Environmental considerations.

    1950's home with plaster wall and wire mesh backing.
    This means the signal has to go through plaster 1/2" - 3/4" thick - Wire mesh, plaster that bleed through the back of the mesh, 3" - 4" dead space, plaster that bleed through the back of the mesh, Wire mesh, plaster 1/2" - 3/4" thick before reaching the next room.
    The home has foil insulation backing around the entire home and 1 interior wall. * That interior wall use to be an exterior wall before an addition was added.


    What does this mean. In room (a), the signal is a 5 /5 the signal in the next room (b) from the same AP is a 1/5 or less. Usually totally unusable. Occasionally it will be but is so degraded it may as well be non existent.

    Solution for me: 1 Node in the outside corners of the home with antennas pointed to the interor, and 1 near the direct center of the home. Makes life a lot easier for me. This diagram is a rough approximation of my home, and the Router & Node setup. It's just a hastily constructed representation.
    There are some closets and 2 hallways, not show which increase the amount of penetration required. Instead of passing through one plaster cross section it requires 2. Because of the opposite wall as in the case of the closet. This further constrains the WiFi signals. The Brown box is a old brick chimney.

    Router coverage.png

    Other considerations:

    My OCD compels me, to use static IPs on what I can. Basically everything in my home has a static IP.
    I have used everything in AiProtection, enabled with no noticeable affect. Neither good nor bad.

    I also removed an Arlo wireless camera system, which insisted on setting up its own WiFi network along side my own. However this still had no where near the impact to my system usage as when I changed the Hue control channel as indicated above. That Hue control channel change was the single greatest improvement to my system hands down. *I also think using mesh had some benefit as it uses the same channel and now I don't have competing channels all over the house as when I was strictly using AP's.

    I think I covered my situation, if there is anything you think I missed give me a shout.
    Last edited: Dec 9, 2018 at 12:12 PM
    JDB likes this.
  5. JDB

    JDB Very Senior Member

    Aug 28, 2016
    Wow, thanks!

    I had the issue again today, interestingly after my power tripped as a result of my combi oven blowing its element!
    Again a reboot of all AP/Nodes fixed it, but it’s very annoying that it can happen with a power restoration!!

    I have set a scheduled reboot of all AP/Nodes for 4am so will see if it helps or makes it worse each morning when I get up the next few days.

    Sent from my iPhone using Tapatalk
  6. HuskyHerder

    HuskyHerder Senior Member

    May 12, 2017
    Oh I have not noticed any issues with the 5G I’ll keep an eye on mine, with the reports above and elsewhere here in the forums.


    1, other thing I did was relocate my Hue hub from within with my entertainment center to a location 15' from any Node, and really high up, next to the ceiling.
    Previously I had used it on a shelf approximately 3' from the top of the wall, and had less than desireable results. Moving it higher also helped out.
    Last edited: Dec 9, 2018 at 5:56 PM