Re: [libvirt] Notes on configuring Open vSwitch, Linux bridge and Libvirt

On 07/12/2013 06:32 PM, Daniel P. Berrange wrote: I had no specific reason on mind. The only test machine I had free was already having a Linux bridge. I thought I'd try on it anyway. Meanwhile, from this networking notes page, http://docs.openstack.org/trunk/openstack-network/admin/content/under_the... it appears that OpenStack uses Linux bridge in conjunction with an OVS bridge: There are four distinct type of virtual networking devices: TAP devices, veth pairs, Linux bridges, and Open vSwitch bridgesFor an ethernet frame to travel from eth0 of virtual machine vm01, to the physical network, it must pass through nine devices inside of the host: TAP vnet0, Linux bridge qbrXXX, veth pair (qcbXXX, qvoXXX), Open vSwitch bridge br-int, veth pair (int-br-eth1, phy-br-eth1), and, finally, the physical network interface card eth1. And further, it notes the distinction between how a Linux bridge and OVS in this context: A Linux bridge behaves like a hub: you can connect multiple (physical or virtual) network interfaces devices to a Linux bridge. Any ethernet frames that come in from one interface attached to the bridge is transmitted to all of the other devices. An Open vSwitch bridge behaves like a virtual switch: network interface devices connect to Open vSwitch bridge's ports, and the ports can be configured much like a physical switch's ports, including VLAN configurations. That's my next test :) -- /kashyap