Odd anomalie


This has just popped up: any thoughts?

“10% of UDP multilateration traffic sent by piaware is not reaching the FlightAware servers. This may indicate a network problem.”


I see that from time to time. Are you using Wi-Fi? In my case I think it happens when multiple streaming/downloading is going on at home. My wi-fi router is a basic N300. If that’s not the case, and the message stays there for a long period of time, restart the RPi, or even the router.


UDP usually gets dropped because it gets buffered and loses out. That could be happening at home, in which case if this hasn’t happened before then have you changed or done anything to coincide with the alert? Eg your router, your settings, a large download somewhere else, more people using the network, wifi interference (if using wifi)? It can also happen beyond your network, at your ISP, even FlightAware’s edge network. It can be tricky to pin down but it’s possible to rule things out and leave likely causes.



if it’s not regular it’s not a problem.

i had it every 5 minutes over 30 minute periods every day.
turned out the problem was the tunnel used by my router (bundles DSL with LTE for better bandwidth)

i switched it off (you can switch it off per computer on the network or just completely depending on how bad you need the extra bandwidth, luckily for me it does not really matter here)

i prodded the network path to Flightaware quite a bit but was not able to find the problem (i tried mtr with the udp option but it’s not really reliable)

one thing i noticed on the flightaware internal network, the second hop before reaching one of the data servers the MTU seems to be 1024 which is quite low and i kinda wonder why.
but i don’t think this is a problem for the udp packets reaching them.

if you have it regularly and want to fix it i can send you instruction to make your pi automatically check his internet connection when piaware announces the problem. but as i said in my case i didn’t have much luck pinpointing the problem.
(i guess it was not really packet loss but the udp packets reaching the flightaware server out of order)