[ovs-discuss] OVS -- Linux interaction

Jesse Gross jesse at nicira.com
Wed Jul 29 00:39:44 UTC 2015


The DPDK path operates differently - the kernel stack in not invoked.
In that case, eth0 does need to be attached to OVS but, again, not in
the same bridge. OVS will sync the routing table from the kernel but
otherwise implements ARP, etc. internally and retains control of the
packet until it is sent out on the physical interface.

On Tue, Jul 28, 2015 at 5:02 PM, Abhishek Verma
<abhishekv.verma at gmail.com> wrote:
> Thanks Jesse.
>
> How does this work when OVS is running in the user space along with DPDK.
> Does OVS again send packets to Linux stack for forwarding? I thought the
> whole point there was NOT to involve the Linux stack.
>
> Asking this since i thought that since eth0 is a part of the OVS bridge, its
> OVS that actually frames the entire packet and sends it out.
>
> Thanks, Abhishek
>
>>
>> It does not make sense to have eth0 in the same bridge as the VXLAN
>> port since they are not in the same network segment (encapsulated vs.
>> not). OVS simply sends tunneled packets as IP to the Linux stack,
>> similar to any other application. These packets do not re-enter OVS
>> unless there is another bridge that is in the normal Linux forwarding
>> path.
>
>



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