On 7 April 2016 at 01:43, Mickey Spiegel <emspi...@us.ibm.com> wrote:
> See comments inline > > Mickey > > > -----Guru Shetty <g...@ovn.org> wrote: ----- > >To: Mickey Spiegel/San Jose/IBM@IBMUS > >From: Guru Shetty <g...@ovn.org> > >Date: 04/06/2016 05:58PM > >Cc: ovs dev <dev@openvswitch.org>, Shi Xin Ruan <steve.r...@cn.ibm.com> > >Subject: Re: [ovs-dev] [PATCH 1/1] Add Static route to logical router > > > > > > > >On 6 April 2016 at 16:55, Mickey Spiegel <emspi...@us.ibm.com> wrote: > >>Steve and Guru, > >> > >> I am not all that concerned about the "valid" column, but I do think > that we will need a different additional column in the near future for > output port. > >> > >> There are three different motivations for allowing output port to be > specified in the static route: > >> 1) In order to support static routes with a link local next hop. If a > link local next hop is used, it is possible that the same link local > address appears on different router ports with different meanings. By > specifying the port, this disambiguates the specific link local next hop > that was desired. > >> Note: Neutron does not yet support static routes with link local next > hop. We need to drive the feature in Neutron as well, optionally allowing a > router interface to be specified in addition to the next hop. > >> 2) This feature should not really be specific to static routes, it > should also apply to dynamic routes when we add that in the future. > Basically anything that looks up an IP address prefix and returns a next > hop and optionally an output port. There are cases where explicitly > specifying the output port makes sense. > > For point 1 and 2, I am not sure whether we should do anything till > there is code in ovn-northd that actually uses it. > > [Mickey] Point of clarification, the proposal is to add an output port > column to the static route table in northd. The question is not whether > there is code in ovn-northd that uses it, it is whether there is code at > the CMS layer that fills this column. Both the features in points 1 and 2 > would make use of this column. > I see what you mean now. > Even if we don't add this column now, if you don't have a separate static > route table, it will make such an addition difficult in the future. > > >> 3) In order to optimize processing of the routing recursion (Steve's > code loops over the router's ports in ovn-northd.c to carry out this > routing recursion), we might want to do it above OVN in an event triggered > manner, rather than every time ovn-northd.c recalculates the flows that it > places into the southbound database. > > I don't think I understand the above point. The static_route I have in > mind need not recursively look through routers. All they need is to see > whether the router peer has the next hop IP address and the packet is just > sent to that router. From there on it is a fresh start. > > [Mickey] By routing recursion I just meant a small walk through all of the > router ports to find which router port has the next hop address. > We are on the same page then (for the above point.) So to summarize, a new table will help if we add the outport as a column and keep it optional. If it is filled, use it. Else, figure out the next hop. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
