Cloned from launchpad blueprint https://blueprints.launchpad.net/neutron/+spec/merge-ovs-bridges.

Description:

The Integration-Bridge(br-int) and Physical-Bridge(s)(br-ethx) configured on the Compute Node are redundant, i.e. there is no additional advantage of configuring them, except for the configuration to separate the ingress and egress flows on the veth pairs.
The contribution allows providing the network services on Compute Node with only One Open Vswitch bridge and eliminating the veth pairs which are used to make connection between the bridges.
The proposed design to achieve the same is as below:
1. There will be only one OVS bridge on a physical host, i.e. only the Integration bridge is created and all the physical NIC’s attach to it.
2. Since the 2 veth pairs (int-br-eth1,phy-br-eth1)  are removed the functionality of stripping/modifying the vlan tags should also be moved as:
     a)	Veth port int-br-ethx functionality should be moved to vnetx/qvoxxx
     b)	Veth port phy-br-ethx functionality should be moved to ethx (port on Integration Bridge)

Comments/Discussions on the proposed solution is appreciated to refine the same.

The flow of packets through various devices is depicted as below:
1. With the existing flow when configured as LibvirtHybridOVSBridgeDriver
         VM(ethx) -- vnetx -- qbrxxx -- qvbxxx -- qvoxxx -(br-int)- int-br-ethx -- phy-br-ethx -(br-ethx)- ethx

     With the proposed solution
         VM(ethx) -- vnetx -- qbrxxx -- qvbxxx -- qvoxxx -(br-int)- ethx

2. With the existing flow when configured as LibvirtOpenVswitchDriver
         VM(ethx) -- vnetx -(br-int)- int-br-ethx -- phy-br-ethx -(br-ethx)- ethx

    With the proposed solution
         VM(ethx) -- vnetx -(br-int)- ethx

Specification URL (additional information):

None