How to make a pingovalka correctly?

Question

Ping

You need to put routers on communication nodes in order to ping them with udp, so that later you can understand where the problems appear. Installed Open WRT on TP link 3600 and ran iperf.
- What is the correct way to set the iperf command to understand the maximum speed without packet loss and it is necessary that the datagrams be 4096 (I did iperf -c .. -u -t 500 -i 5 -b 800m -d 4096)
- What is the best way to monitor such device, zabix is ​​too fat, are there any alternatives?
- How to implement such a thing in general?
I would be very grateful.