[ovs-dev] [RFC PATCH 4/8] ofproto: Implement OpenFlow 1.3 meter table.

[Ben Pfaff]

On Tue, Jun 25, 2013 at 12:38:32PM -0700, Ben Pfaff wrote:
> We can add a "bad meter" extension error very easily by editing
> ofp-errors.h.  Feel free to use the Nicira extension namespace for
> this, or you could easily add a Nokia-Siemens extension namespace by
> adding a *_VENDOR_ID to openflow-common.h.

There was some discussion today of the same issue on the OpenFlow
working group mailing list at ONF.  Jean Tourrilhes, the spec editor,
suggested using OFPMMFC_INVALID_METER for this kind of error.  I
replied:

> OFPMMFC are supposed to be "meter mod" errors.  Instructions are
> typically part of flow-mods so I'm not sure whether it's appropriate
> to issue an OFPMMFC error in reply.

and Jean followed up:

> Yes, I missed that subtle point. I don't see the harm in reusing those
> error code in a flow-mod, there is no risk in ambiguity. It's a bit
> like when we have a bad action, we use the generic action codes.
> Please file a ticket and we will update the spec to make it explicit
> that you need to use those error codes in that context.

so I suggest we should use OFPMMFC_INVALID_METER.