Hi guys.
I dont know when this problem started but I believe its not a long term problem as I would have noticed it sooner.
Basically every 30 seconds most traffic on my LAN stops responding for about a second or two, and this includes internet traffic.
Some info.
Two openwrt devices as switches, one of them is also wifi access point.
One pfsense device as firewall connected to first openwrt switch (which is also the WAP)
If I hold down a key in ssh, to anything whether its remote server, or a lan device including second openwrt switch and pfsense I get a sticky cursor for 1-2 seconds then it carries on.
If I do this on the main openwrt switch itself, which is what the ethernet from my PC is connected to as well as laptop via wifi, then it is fine.
Now I have also discovered the following.
If I disconnect the second openwrt switch from the first (pull out the cable), the issues stop. If I disconnect everything from that second switch and keep it connected, the issues do not stop.
Every 30 seconds there is a small spike of traffic on my main PC, the packet loss coincides with these traffic spikes, the spikes still occur when the second switch is disconnected, but there is no loss of traffic then. I have tried to diagnose whats going on here, as my laptop on windows doesnt have the same spikes, I reduced the size of the spikes disabling network discovery/upnp services, however the smaller spike remains and is from the kernel directly (system process).
Given the timings matching up I think the spikes might be related, and possible making the two openwrt's temporarily flood each other or something, so maybe it is multicast traffic I dont know.
The spikes stop when I put the PC in ipv6 only. However the laptop still gets the loss every 30 seconds to the second switch, also this happens still even when I disconnect my PC from the network, so the spikes are not the cause although incredibly coincidental they are the same timing.
This is one of the oddest and most frustrating network problems I have ever seen and would appreciate any advice.