Hi All,

I've been trying to troubleshoot a strange issue I'm having, and what I've managed to find online hasn't solved the issue so I need a little more assistance. The 2.4 GHz network is 802.11g/n and the 5 GHz is 802.11ac.

When I changed ISPs I received a Huawei HG659 with my VDSL connection and have been using that as both the modem and router since we have only two regular users. Devices have been split between the 2.4 GHz and 5 GHz networks based on requirements, e.g. Printer is on the 2.4 GHz, Laptops on the 5 GHz. Everything was working without issue for around 1 1/2 years. A few weeks ago an intermittent connection issue started that would cause all devices to "lose" the 5 GHz network and go through a cycle of trying to reconnect to it, then managing to connect but not having internet, and then eventually getting internet connection back.

While this happens, devices connected via wired LAN and ones on the 2.4 GHz network continue to have normal access/usage and are unaffected. If I move any of the devices that were experiencing disconnects onto the 2.4 GHz network, then they stop having issues and work as normal. I haven't noticed any trend or pattern to the disconnects other than it only happens on the 5 GHz network.

My first thought was that the 5 GHz equipment in the router was dying, so I dugout an older D-Link DIR850L router that I had in the cupboard and bridged it with the HG659 acting as the modem. I set everything up, and to my surprise, the 5 GHz disconnects kept happening. Again the 2.4 GHz and wired connections were fine. I've tried checking settings on both routers to make sure they were on sensible options, and as far as my knowledge goes, they appeared to be configured correctly. I also doubted it was a settings issue since the HG659 had gone from working to problematic without any changes being made.

I've used a wifi scanning app on my tablet to check for other networks clashing with ours. There is a little congestion on the 2.4 GHz, but we're surrounded by houses (not apartments) so they're significantly weaker than our network. I only pick up other's 5 GHz networks in some parts of the house and the channels don't clash.

The only internet/network related thing I can think of is that it started roughly around the time Chorus contractors started installing fibre in our street, but I think that is a red herring and that any issues they might cause should affect all three network connection methods.

Summary of the main things I've tried:

 

1. Changed routers.
2. Changed which frequency devices were attached to.
3. Checked the behaviour on multiple devices.
4. Tried to identify patterns.
5. Checked router settings for:

    

    

   1. Channel width - 20/40 for 2.4 GHz and 20/40/80 for 5 GHz.
   2. No connection schedule set.
   3. Channel auto scan - on.
   4. Group key update interval - 3600 seconds (default for both 2.4/5 GHz).
   5. 5 GHz 802.11 mode - set to 802.11ac only to ensure there wasn't any strange switching going on.
   6. Security - Both 2.4/5 GHz using WPA2 with AES.
   7. DHCP lease time - 10080 minutes (7 days).
   8. Checked number of devices registered to 5 GHz to make sure it wasn't too many. Culled a few friends devices from the list to double check.

    

6. Scanned for wifi conflicts with neighbours.
7. Tested range - Still happens even within two metres of the router

Some things I haven't tried:

 

1. Changing modems - although I think if this was the problem then it should affect all connection methods.
2. Checking if all devices disconnect at the same time - Realised I didn't know the answer to this while writing this post.
3. Changing ISP - Same thoughts as #1 above

Anyone else experience this issue before or have advice on further troubleshooting?