On Fri, Feb 07, 2014 at 08:15:49AM -0800, Ben Pfaff wrote: > On Wed, Feb 05, 2014 at 05:54:38PM +0900, Simon Horman wrote: > > * Ben has explained to me that there has been a change of direction > > at the ONF with regards to MPLS and VLAN tag ordering. As per > > his changelog for "Always insert MPLS labels after VLAN tags", > > the situation is now as follows: > > > > * OpenFlow 1.1 and 1.2 always inserted MPLS labels after VLAN tags. > > * OpenFlow 1.3 and 1.4 insert MPLS labels before VLAN tags. > > * OpenFlow 1.3.4 and 1.5, both in preparation, recognize that the change > > in 1.3 was an error and revert it. > > > > With this in mind only OF1.4 specifies a requirement for inserting MPLS > > labels before VLAN tags. This appears to be an abbertation at this > > point. > > > > Ben's suggestion as per his patch "Always insert MPLS labels after VLAN > > tags" is that Open vSwtich should only support inserting MPLS labels > > after VLAN tags. I agree with this. And to this end I have > > updated the MPLS code for the kernel datapath (this patch). > > I spoke to Jesse briefly about MPLS versus VLANs a few days ago. He > expressed a concern about the larger problem of figuring out how all the > various forms of tags should interact: VLAN, MPLS, PBB, and others that > I can't think of at the moment. It would be more consistent from this > higher point of view if "push" and "pop" actions always acted in a > predictable place. > > I agree with that point, but it still stands that I don't know of a > well-defined way for VLAN-inside-MPLS to function. So here is my > proposal for you and Jesse to consider: > > - The datapath push_mpls action is well-defined when no VLAN is > present. Great. > > - Declare the behavior of the datapath push_mpls action to be > undefined in the presence of a VLAN for now, since we don't > really know what should happen. For now, make the datapaths > reject any flow that does push_mpls in the presence of a VLAN. > Later, we can redefine that case as we please since userspace > should not depend on the previous behavior. > > - Modify userspace to pop_vlan, push_mpls, push_vlan if > necessary to avoid the undefined behavior. > > Jesse, is that reasonable?
FWIW, that sounds very reasonable to me. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
