Hi Folks, 

Please excuse me for posting this naive question, but I searched online and 
looked at the source code and haven't figured this out.

What is the difference between a port created with type=internal and type=tap?

It seems to me that if I create a port with type=tap, then OVS creates the tap 
(makes the ioctl calls to /dev/net/tun) and opens the user-side (raw 
block-device side) of the tap. But this seems to be exactly what OVS does for 
internal ports - I read in INSTALL.userspace that a tap is created for every 
internal port. However, I am using the OVS kernel module so I don't know if 
that document applies.

Since internal and tap ports are so similar, what are the use-cases for 
tap-ports for which internal ports are inappropriate?

And just to spell my assumptions out a bit further - it seems to me that in the 
common use-case of attaching a VM to an OVS bridge, a tap is created externally 
to OVS (e.g. by scripts or cloud management software) and the tap is added as a 
system port to OVS so that OVS handles the kernel side of the tap, and the VM 
gets the user-side of the tap. So VMs are not a use-case for OVS ports of 
type=tap. Is that correct?


thanks and regards,
Pino


-- 
Pino de Candia
Software Engineer, Midokura.com

_______________________________________________
discuss mailing list
[email protected]
http://openvswitch.org/mailman/listinfo/discuss

Reply via email to