Strange delay for every 10th ping

[Chris Green]

On Tue, Feb 01, 2022 at 10:03:14PM +0000, Chris Green wrote:
> On Tue, Feb 01, 2022 at 09:56:56PM +0000, Colin Law wrote:
> > On Tue, 1 Feb 2022 at 21:50, Chris Green <cl at isbd.net> wrote:
> > >
> > > Can anyone suggest why I should see this delay on every 10th ping
> > > across my home LAN:-
> > 
> > Do you see the same thing pinging the same address from another system
> > connected via wifi?
> > 
> Not sure, not many WiFi systems here.
> 
> 
> > Do you see the same thing from this system, pinging a different
> > system, still via wifi?
> > 
> Yes.
> 
> 
> I've tried to a different WiFi AP, a very similar pattern of delays
> and dropped packets so, initially anyway, it looks like an issue with
> the 21.10 system's WiFi.
> 
> I'll try a 5Ghz AP if I can.
> 
A connection to a different AP at 5Ghz is a lot better but there are
still small delays every so often:-

    chris$ ping dns
    PING dns (192.168.1.2) 56(84) bytes of data.
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=1 ttl=64 time=7.15 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=2 ttl=64 time=5.80 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=3 ttl=64 time=2.85 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=4 ttl=64 time=11.9 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=5 ttl=64 time=3.88 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=6 ttl=64 time=8.37 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=7 ttl=64 time=7.29 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=8 ttl=64 time=5.63 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=9 ttl=64 time=4.43 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=10 ttl=64 time=3.32 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=11 ttl=64 time=21.3 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=12 ttl=64 time=2.79 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=13 ttl=64 time=7.58 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=14 ttl=64 time=5.59 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=15 ttl=64 time=3.90 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=16 ttl=64 time=2.49 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=17 ttl=64 time=10.3 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=18 ttl=64 time=8.58 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=19 ttl=64 time=7.51 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=20 ttl=64 time=2.94 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=21 ttl=64 time=2.94 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=22 ttl=64 time=52.0 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=23 ttl=64 time=89.9 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=24 ttl=64 time=9.65 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=25 ttl=64 time=7.50 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=26 ttl=64 time=6.20 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=27 ttl=64 time=4.32 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=28 ttl=64 time=12.3 ms
    64 bytes from dns.zbmc.eu (192.168.1.2): icmp_seq=29 ttl=64 time=10.2 ms
    ^C
    --- dns ping statistics ---
    29 packets transmitted, 29 received, 0% packet loss, time 28048ms
    rtt min/avg/max/mdev = 2.488/11.334/89.858/17.401 ms

This is with the laptop right next to the AP (within a metre) so you'd expect
better really.  There's absolutely nothing else going on.


-- 
Chris Green