[ovs-discuss] OpenVSwitch flow forwarding

Jesse Gross jesse at nicira.com
Tue Feb 7 01:42:39 UTC 2012

On Mon, Feb 6, 2012 at 3:50 PM, Masood Moshref Javadi
<masood.moshref.j at gmail.com> wrote:
> I want to figure out the workflow of a packet in the openvswitch (using the
> kernel module). Basically, I have these questions:
> 1) When a flow comes where it will be compared to the rules?

Packets for new flows are handled in userspace with a classifier that
is capable of handling wildcards.  Future packets in that flow are
handled by an exact match table in the kernel.

> 2) Is there any difference between rules with wildcard field and exact
> rules?
> 3) what is the effect of huge number of rules on the performance of
> openvswitch

The userspace table is mostly proportional to the number of unique
sets of wildcards.  The kernel table is not affected by the number of
OpenFlow rules.

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