Fluctuating Ping

[adam_carter_607]

I have deployed a Zonedirector 1100 and 6 x zf7372 APs. The APs are connected to the same PoE switch as the ZoneDirector.

APs are not configured for mesh mode.

Signal coverage is good, but I am getting fluctuating pings when testing from various devices - it follows the pattern 1 good ping (1ms), 1 average pint (~100ms), then one higher ping (200-300ms) - then repeat.

For testing I am pinging the IP address of the ZoneDirector to eliminate any other network issues. Checking the logs it shows the channel selection and client association to be static - I am not moving around but in a fixed position and the ZD reports this to be accurate:

Reply from 10.10.1.20: bytes=32 time=2ms TTL=64
Reply from 10.10.1.20: bytes=32 time=10ms TTL=64
Reply from 10.10.1.20: bytes=32 time=211ms TTL=64
Reply from 10.10.1.20: bytes=32 time=136ms TTL=64
Reply from 10.10.1.20: bytes=32 time<1ms TTL=64
Reply from 10.10.1.20: bytes=32 time=2ms TTL=64
Reply from 10.10.1.20: bytes=32 time=133ms TTL=64
Reply from 10.10.1.20: bytes=32 time=10ms TTL=64
Reply from 10.10.1.20: bytes=32 time=249ms TTL=64
Reply from 10.10.1.20: bytes=32 time=2ms TTL=64

I have tested on both 2.4GHz and 5GHz channels but I get the same result.
The pings never drop and I get good throughput when transferring data, but I am not sure the latency should fluctuate as much as this.

Firmware on ZD is the latest ( 9.6.1.0 build 15)
Does anyone have any ideas?

Thanks

[keith_redfield]

Glad to hear you found the issue, and especially appreciate you sharing it.

Ping is a great way to test connectivity, but that's about all it's good for. ICMP response are generally given very low priority - so if a system is busy that's the first thing it will drop - even when other traffic is running smoothly (this is true of almost anything with a network interface, not just our gear). It works best as a diagnostic when the packets transit the suspect device rather than terminate there.