> > > > I have a reproducible problem on 11.1-STABLE where, during a longterm > > > > iperf3 session, some packets are lost every time ARP is refreshed (every > > > > net.link.ether.inet.max_age seconds). Checking with tcpdump, I can > > > > indeed see that the packet loss is happening as the hosts are doing > > > > ARP request/reply. > > > I'll take a look. Indeed, the intended behaviour is to proactively > > > refresh the record. > > > Is the situation the same with forwarding and locally-originated traffic? > > > With local TCP socket inpcb route caching might come into play. > > > > My testing is with locally-originated UDP traffic (iperf3 -u). Haven't > > tested what happens if the box is forwarding the traffic - however, I > > believe TCP socket inpcb route caching should not be relevant for the > > UDP traffic? (But there is also a TCP transaction between the iperf3 > > sender and the iperf3 receiver at the *start* of the iperf3 session.) > > > > In any case, I will also test what happens if the box is forwarding > > the traffic. > > And thank you for that suggestion! The packet loss during ARP refresh > (of the destination address connected to the output interface) does > *not* happen when the box is forwarding! It only happens with locally > generated traffic.
Checking once per second with "arp -n <destination IP>" I can see the following behavior with net.link.ether.inet.max_age=120: - Locally generated traffic: The ARP entry is refreshed after net.link.ether.inet.max_age seconds - which presumably means it actually expires first. And there is some packet loss. - Transit traffic (the box is forwarding): The ARP entry is refreshed 5 seconds *before* net.link.ether.inet.max_age has passed, and there is no packet loss. Steinar Haug, Nethelp consulting, sth...@nethelp.no _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
