Troubleshooting ping drop packet wit same interval
The issue appear between 10G Qnap switch and the TPlink router. TPLink has a 2.5GB ethernet, which connects to 10G ethernet of Qnap switch. Sometimes, ping drop package, they have almost same interval!
% ping 192.168.1.254
PING 192.168.1.254 (192.168.1.254): 56 data bytes
64 bytes from 192.168.1.254: icmp_seq=0 ttl=64 time=0.464 ms
Request timeout for icmp_seq 1
64 bytes from 192.168.1.254: icmp_seq=2 ttl=64 time=0.431 ms
64 bytes from 192.168.1.254: icmp_seq=3 ttl=64 time=0.399 ms
64 bytes from 192.168.1.254: icmp_seq=4 ttl=64 time=0.302 ms
64 bytes from 192.168.1.254: icmp_seq=5 ttl=64 time=0.356 ms
64 bytes from 192.168.1.254: icmp_seq=6 ttl=64 time=0.461 ms
64 bytes from 192.168.1.254: icmp_seq=7 ttl=64 time=0.495 ms
64 bytes from 192.168.1.254: icmp_seq=8 ttl=64 time=0.450 ms
64 bytes from 192.168.1.254: icmp_seq=9 ttl=64 time=0.573 ms
64 bytes from 192.168.1.254: icmp_seq=10 ttl=64 time=0.282 ms
64 bytes from 192.168.1.254: icmp_seq=11 ttl=64 time=0.374 ms
64 bytes from 192.168.1.254: icmp_seq=12 ttl=64 time=0.604 ms
64 bytes from 192.168.1.254: icmp_seq=13 ttl=64 time=0.438 ms
64 bytes from 192.168.1.254: icmp_seq=14 ttl=64 time=0.418 ms
64 bytes from 192.168.1.254: icmp_seq=15 ttl=64 time=0.446 ms
64 bytes from 192.168.1.254: icmp_seq=16 ttl=64 time=0.570 ms
64 bytes from 192.168.1.254: icmp_seq=17 ttl=64 time=0.753 ms
64 bytes from 192.168.1.254: icmp_seq=18 ttl=64 time=0.456 ms
64 bytes from 192.168.1.254: icmp_seq=19 ttl=64 time=0.530 ms
64 bytes from 192.168.1.254: icmp_seq=20 ttl=64 time=0.531 ms
64 bytes from 192.168.1.254: icmp_seq=21 ttl=64 time=0.480 ms
64 bytes from 192.168.1.254: icmp_seq=22 ttl=64 time=0.498 ms
64 bytes from 192.168.1.254: icmp_seq=23 ttl=64 time=0.498 ms
64 bytes from 192.168.1.254: icmp_seq=24 ttl=64 time=0.465 ms
Request timeout for icmp_seq 25
64 bytes from 192.168.1.254: icmp_seq=26 ttl=64 time=0.493 ms
64 bytes from 192.168.1.254: icmp_seq=27 ttl=64 time=0.520 ms
64 bytes from 192.168.1.254: icmp_seq=28 ttl=64 time=0.462 ms
64 bytes from 192.168.1.254: icmp_seq=29 ttl=64 time=0.459 ms
64 bytes from 192.168.1.254: icmp_seq=30 ttl=64 time=0.535 ms
64 bytes from 192.168.1.254: icmp_seq=31 ttl=64 time=0.468 ms
64 bytes from 192.168.1.254: icmp_seq=32 ttl=64 time=0.505 ms
64 bytes from 192.168.1.254: icmp_seq=33 ttl=64 time=0.539 ms
64 bytes from 192.168.1.254: icmp_seq=34 ttl=64 time=0.515 ms
64 bytes from 192.168.1.254: icmp_seq=35 ttl=64 time=0.504 ms
64 bytes from 192.168.1.254: icmp_seq=36 ttl=64 time=0.519 ms
64 bytes from 192.168.1.254: icmp_seq=37 ttl=64 time=0.415 ms
64 bytes from 192.168.1.254: icmp_seq=38 ttl=64 time=0.415 ms
64 bytes from 192.168.1.254: icmp_seq=39 ttl=64 time=0.384 ms
64 bytes from 192.168.1.254: icmp_seq=40 ttl=64 time=0.443 ms
64 bytes from 192.168.1.254: icmp_seq=41 ttl=64 time=0.456 ms
64 bytes from 192.168.1.254: icmp_seq=42 ttl=64 time=0.349 ms
64 bytes from 192.168.1.254: icmp_seq=43 ttl=64 time=0.345 ms
64 bytes from 192.168.1.254: icmp_seq=44 ttl=64 time=0.272 ms
64 bytes from 192.168.1.254: icmp_seq=45 ttl=64 time=0.456 ms
64 bytes from 192.168.1.254: icmp_seq=46 ttl=64 time=0.523 ms
64 bytes from 192.168.1.254: icmp_seq=47 ttl=64 time=0.553 ms
64 bytes from 192.168.1.254: icmp_seq=48 ttl=64 time=0.389 ms
Request timeout for icmp_seq 49
64 bytes from 192.168.1.254: icmp_seq=50 ttl=64 time=0.417 ms
64 bytes from 192.168.1.254: icmp_seq=51 ttl=64 time=0.433 ms
64 bytes from 192.168.1.254: icmp_seq=52 ttl=64 time=0.467 ms
64 bytes from 192.168.1.254: icmp_seq=53 ttl=64 time=0.417 ms
^C
--- 192.168.1.254 ping statistics ---
54 packets transmitted, 51 packets received, 5.6% packet loss
round-trip min/avg/max/stddev = 0.272/0.461/0.753/0.083 ms
% Possible issue
After a month, I found that in Qnap web console, the flow control on the switch port, always flicking, sometimes enable, sometimes disable. Due to this behavior, I think could be the issue with the connection between them could try to re-established again and again.
Then I disabled flow-control from switch side, because I can not find the port settings in TPlink router.
Flow control
Enable flow control is to reduce packet dropping, but auto-negotiate can cause issue. Most of time both ends of ethernet can leave to auto-negotiate, but prefer to set one side manual if possible, especially two side has different highest speed.