reproduced on ovn2.11-2.11.1-19: [root@dell-per740-12 ~]# ip netns exec server0 ping6 3000::1 -c 2 PING 3000::1(3000::1) 56 data bytes --- 3000::1 ping statistics --- 2 packets transmitted, 0 received, 100% packet loss, time 12ms [root@dell-per740-12 ~]# grep ofproto_dpif_upcall /var/log/openvswitch/ovs-vswitchd.log 2019-11-28T06:16:54.594Z|00001|ofproto_dpif_upcall(handler52)|INFO|received packet on unassociated datapath port 4294967295 2019-11-28T06:16:54.607Z|00001|ofproto_dpif_upcall(revalidator85)|WARN|Failed to acquire udpif_key corresponding to unexpected flow (Invalid argument): ufid:38c928be-6f25-41e4-a84a-3f7cafa92c1c 2019-11-28T06:16:55.604Z|00002|ofproto_dpif_upcall(handler52)|INFO|received packet on unassociated datapath port 4294967295 2019-11-28T06:16:55.608Z|00002|ofproto_dpif_upcall(revalidator85)|WARN|Failed to acquire udpif_key corresponding to unexpected flow (Invalid argument): ufid:64bb5f22-8c0c-43ef-8af7-1d35aa1dd891 <==== error in ovs log [root@dell-per740-12 ~]# rpm -qa | grep -E "openvswitch|ovn" ovn2.11-2.11.1-19.el8fdp.x86_64 openvswitch2.11-2.11.0-26.el8fdp.x86_64 ovn2.11-central-2.11.1-19.el8fdp.x86_64 openvswitch-selinux-extra-policy-1.0-19.el8fdp.noarch ovn2.11-host-2.11.1-19.el8fdp.x86_64 [root@dell-per740-12 bz1776973]# ip netns exec server1 tcpdump -i any -nnle tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes ^C 0 packets captured 0 packets received by filter 0 packets dropped by kernel <==== no NS received Verified on ovn2.11-2.11.1-20: [root@dell-per740-12 ~]# ip netns exec server0 ping6 3000::1 -c 2 PING 3000::1(3000::1) 56 data bytes 64 bytes from 3000::1: icmp_seq=2 ttl=63 time=2.75 ms --- 3000::1 ping statistics --- 2 packets transmitted, 1 received, 50% packet loss, time 44ms rtt min/avg/max/mdev = 2.745/2.745/2.745/0.000 ms <==== passed [root@dell-per740-12 ~]# grep ofproto_dpif_upcall /var/log/openvswitch/ovs-vswitchd.log 2019-11-28T06:16:54.594Z|00001|ofproto_dpif_upcall(handler52)|INFO|received packet on unassociated datapath port 4294967295 2019-11-28T06:16:54.607Z|00001|ofproto_dpif_upcall(revalidator85)|WARN|Failed to acquire udpif_key corresponding to unexpected flow (Invalid argument): ufid:38c928be-6f25-41e4-a84a-3f7cafa92c1c 2019-11-28T06:16:55.604Z|00002|ofproto_dpif_upcall(handler52)|INFO|received packet on unassociated datapath port 4294967295 2019-11-28T06:16:55.608Z|00002|ofproto_dpif_upcall(revalidator85)|WARN|Failed to acquire udpif_key corresponding to unexpected flow (Invalid argument): ufid:64bb5f22-8c0c-43ef-8af7-1d35aa1dd891 2019-11-28T06:20:54.767Z|00001|ofproto_dpif_upcall(handler66)|INFO|received packet on unassociated datapath port 4294967295 2019-11-28T06:20:54.768Z|00001|ofproto_dpif_upcall(revalidator97)|WARN|Failed to acquire udpif_key corresponding to unexpected flow (Invalid argument): ufid:2d287088-c56f-47ab-a92b-5bd1a7121da6 <==== also get error in log [root@dell-per740-12 ~]# rpm -qa | grep -E "openvswitch|ovn" ovn2.11-central-2.11.1-20.el8fdp.x86_64 openvswitch2.11-2.11.0-26.el8fdp.x86_64 ovn2.11-2.11.1-20.el8fdp.x86_64 ovn2.11-host-2.11.1-20.el8fdp.x86_64 openvswitch-selinux-extra-policy-1.0-19.el8fdp.noarch [root@dell-per740-12 bz1776973]# ip netns exec server1 tcpdump -i any -nnle tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes 01:20:54.754719 M 00:de:ad:ff:01:03 ethertype IPv6 (0x86dd), length 88: 2001::1 > ff02::1:ff00:1: ICMP6, neighbor solicitation, who has 3000::1, length 32 <=== NS received 01:20:54.754770 Out fa:9b:16:f8:23:a4 ethertype IPv6 (0x86dd), length 88: 3000::1 > 2001::1: ICMP6, neighbor advertisement, tgt is 3000::1, length 32 01:20:55.603582 Out fa:9b:16:f8:23:a4 ethertype IPv6 (0x86dd), length 72: fe80::f89b:16ff:fef8:23a4 > ff02::2: ICMP6, router solicitation, length 16 01:20:55.796673 In 00:de:ad:ff:01:03 ethertype IPv6 (0x86dd), length 120: 3000::55 > 3000::1: ICMP6, echo request, seq 2, length 64 01:20:55.796747 Out fa:9b:16:f8:23:a4 ethertype IPv6 (0x86dd), length 88: 3000::1 > ff02::1:ff00:55: ICMP6, neighbor solicitation, who has 3000::55, length 32 01:20:55.797813 In 00:de:ad:ff:01:03 ethertype IPv6 (0x86dd), length 88: 3000::55 > 3000::1: ICMP6, neighbor advertisement, tgt is 3000::55, length 32 01:20:55.797846 Out fa:9b:16:f8:23:a4 ethertype IPv6 (0x86dd), length 120: 3000::1 > 3000::55: ICMP6, echo reply, seq 2, length 64 set VERIFIED