The difference between the first one and the second will be the security groups. When security groups are not enable, the tap interface gets connected directly to the br-int. Another good tutorial on Neutron will be this one: http://openstack.redhat.com/Networking_in_too_much_detail Cheers, Edgar On 8/28/14, 6:50 AM, "George Shuklin" <george.shuklin at gmail.com> wrote: >I found something strange I can't solve by myself. > >Sometimes I getting configuration where VMs traffic get to the gre >tunnes via following sequence: tap->qbr->qvb->qvo->br-int->br-tun->eth0. >It described here: >http://docs.openstack.org/grizzly/openstack-network/admin/content/under_th >e_hood_openvswitch.html > >But sometimes I getting very different configuration: >tap->br-int->br-tun->eth0. It working, and working fine. And I just >can't find option or configuration difference, or combination of both >which cause switching between 'simple' and 'normal' scheme. I feel like >I don't understand something basic and something important. > >Any ideas? Thanks! > >_______________________________________________ >OpenStack-operators mailing list >OpenStack-operators at lists.openstack.org >http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators