Someone else has been on the setup and things have changed a bit.
He said he entered a flow entry - but I did not have time to follow up. I am in R/O mode. :-)
br-eth0 was brought up and that may have changed the behavior.
Now ARP is reach the other machine, and I can see the traffic on eth0, phy-br-eth0 and int-br-eth0.
But there is not ARP reply. The ARPs are not getting to any of the TAP interfaces (but I only did once).
The br-int seems to be dropping now.
BTW, one TAP interface is not there as VM was brought down but ovs-vsctl has it.
stack@esg-dell-c4-s10:~/devstack$ ovs-dpctl show br-eth0 flows
system@br-eth0:
lookups: hit:658100 missed:119465 lost:0
flows: 27
port 0: br-eth0 (internal)
port 6: eth0
port 9: phy-br-eth0
ovs-dpctl: opening datapath flows failed (No such device)
stack@esg-dell-c4-s10:~/devstack$ sudo ovs-ofctl dump-flows br-eth0
NXST_FLOW reply (xid=0x4):
cookie=0x0, duration=54070.378s, table=0, n_packets=80, n_bytes=6552, priority=2,in_port=9 actions=drop
cookie=0x0, duration=54070.663s, table=0, n_packets=632974, n_bytes=79155773, priority=1 actions=NORMAL
stack@esg-dell-c4-s10:~/devstack$ ovs-dpctl show br-eth0 flows
system@br-eth0:
lookups: hit:660125 missed:119838 lost:0
flows: 30
port 0: br-eth0 (internal)
port 6: eth0
port 9: phy-br-eth0
ovs-dpctl: opening datapath flows failed (No such device)
stack@esg-dell-c4-s10:~/devstack$ sudo ovs-ofctl dump-flows br-int
NXST_FLOW reply (xid=0x4):
cookie=0x0, duration=54307.045s, table=0, n_packets=608686, n_bytes=77906470, priority=2,in_port=18 actions=drop
cookie=0x0, duration=54307.359s, table=0, n_packets=14395, n_bytes=2748282, priority=1 actions=NORMAL
stack@esg-dell-c4-s10:~/devstack$ ovs-dpctl show br-int flows
system@br-int:
lookups: hit:631616 missed:143682 lost:0
flows: 26
port 0: br-int (internal)
Sep 21 03:00:32|00001|netdev_linux|WARN|/sys/class/net/tap26583155-34/carrier: open failed: No such file or directory
port 1: tap26583155-34 (internal)
port 14: tapd1802d22-b4
port 15: tapfa0e7fcf-8d
port 16: tap5eb27feb-05
port 18: int-br-eth0
ovs-dpctl: opening datapath flows failed (No such device)