[ovs-discuss] CHECK_OVERLAP and identical flows

Ben Pfaff blp at nicira.com
Tue Jan 6 23:09:40 UTC 2015


On Tue, Jan 06, 2015 at 05:16:12PM -0500, Anup Khadka wrote:
> Hi, during an add-flow request with CHECK_OVERLAP set, if an identical flow
> exists in the table, what should be the expected behavior?
> 
> Should we reject it and send an error with OFPFMFC_OVERLAP code back to the
> controller?
> 
> The current OVS code transforms add to modify if there is an existing
> identical flow even if CHECK_OVERLAP is set.
> 
> I guess the primary question is: are identical flows not overlapping flows?
> I thought the OpenFlow standard was sort of ambiguous when it defined
> overlapping flows:
> "Two flow entries overlap if a single packet may match both, and both
> entries have the same priority"

This will be clarified in the next OpenFlow 1.3.x release. in the
OpenFlow extensibility working group.  The new wording is: "Two flow
entries overlap if a single packet may match both, and both flow
entries have the same priority, but the two flow entries don't have
the exact same match."



More information about the discuss mailing list