[ovs-discuss] Fwd: question regarding openflow flow table

Ben Pfaff blp at nicira.com
Thu Dec 16 17:13:32 UTC 2010

On Thu, Dec 16, 2010 at 04:11:16PM +0000, Haris Rotsos wrote:
> Following your answer, the insertion of exact match rules in the
> classifier table doesn't have an impact on the switching performance
> and is the default behaviour expected from openvswitch?

(Is that what you were really asking about before, or is it a new
question?)  Exact match rules can get inserted into the classifier
table, in older versions of OVS, because OVS has some additional flow
fields that are not visible to OpenFlow 1.0 controllers.  When an
OpenFlow 1.0 controller inserts a flow, therefore, those fields will
always be wildcarded, and therefore an OpenFlow 1.0 controller cannot
actually insert exact-match rules into an OVS flow table.

This is confusing, which is one reason why recent OVS does not expose a
separate exact-match flow table.

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