Comment 3 for bug 1876092

Hi, Rodolfo, Think you for your information. I indeed used OVS backend, You are right, The neutron codes don't support FLAT network with DVR router. Due to lack the DVR flows about Flat network, the mac of qr-* don't be modified as host DVR mac, this will result in the fdb entry about FLAT network's qr-* in br-int become disorder(sometimes it's right, the qr-*'s mac map to the qr-* port; sometimes it's errror, the qr-*'s mac map to the int-br-* patch port). And the same router's qr-* in different compute nodes have same mac and ip, when we empty the the fdb entries of br-int, the first repley packet of VM will be broadcasted to all qr-* in defferent node. So I think this is the reason of DUP reply.