[ovs-discuss] Packet path from guest to host doc

[Ben Pfaff]

On Fri, May 03, 2013 at 11:21:41PM -0700, Palani Chinnakannan wrote:
>     I am trying to understand the packet path  from a guest VM to the entry
> point into openvswitch daemon in the host.   I assume that the packet
> enters the guest kernel, walks the guest net stack and somehow reaches the
> vswitchd daemon in the host. How does this happen?.  Any pointers to wiki
> docs is what  I am looking for.

The packet goes through a hypervisor specific kernel driver in the host,
e.g. "netback" for Xen.

> I see this vnet0 interface that appears on the north of the openswitch.  Is
> this a tuptap interface.

How can we know what you are using?  You can identify it yourself,
e.g. "ethtool -i vnet0".

> Is it possible to remove this interface out of the switch by using
> ovs-vsctl and then drictyly read/write to this interface.

If you want.

> Ultimately, my goal is to write a quantum plugin that can directly talk to
> the VM.  I am exploring this for a new switch we are developing.

I am surprised that you are using Open vSwitch at all if your goal is to
develop a switch.