On Thu, Oct 17, 2013 at 02:59:07PM -0700, Jarno Rajahalme wrote: > > On Oct 17, 2013, at 11:47 AM, Ben Pfaff <b...@nicira.com> wrote: > > > On Wed, Oct 16, 2013 at 04:16:05PM -0700, Jarno Rajahalme wrote: > >> Signed-off-by: Jarno Rajahalme <jrajaha...@nicira.com> > > > > This raises an issue that I had resolved one way, and you resolved > > another (even if you did not realize it). I am not certain that I chose > > the right way, so let me present the issue for discussion. > > > > The definition of the "set-ecn" action in OpenFlow 1.1 is: > > > > Replace the existing IP ECN value and up- > > date the IP checksum. Only applies to IPv4 > > packets. > > > > It's the "only applies to IPv4" that concerns me. According to a plain > > reading of the specification, this makes the action do nothing (or be > > invalid) for IPv6. But a spec standards lawyer[*] would notice that > > OF1.1 did not support IPv6, and so "only applies to IPv4" could be read > > as meaning that the action does not apply to the other protocols that > > OF1.1 does support (e.g. it is meaningless for ARP, MPLS, ?) > > I did not read it in the sense of "must not apply on IPv6". Considering that > even OF1.1 *has* minimal support for IPv6, in the sense that it is legal to > match on IPv6 ether type, in which case my reading of the spec would change > the ECN in a case where your more strict reading would not. > > > [*] Catch me playing a spec standards lawyer in a special guest > > appearance on an upcoming episode of "CSI: OpenFlow", next > > Wednesday at ten (nine central)! > > > > I interpreted this according to the plain wording in other cases, and > > so, for example, OFPAT_SET_DSCP only sets the DSCP for IPv4 and becomes > > a no-op for IPv6. Maybe I was wrong. Either way, I would like to be > > consistent here. > > I noticed this, and kept wondering why, without thinking to read the spec > that strictly. > I think your reading is safer, since a controller might actually depend on it.
OK. I'm happy with that (also would have been happy the other way). Thanks. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
