[ovs-dev] [PATCH 1/4] ovn : Setup a controller for br-int

Ben Pfaff blp at ovn.org
Wed Nov 11 00:36:26 UTC 2015


Sorry it's taken me so long to get back to this.

It works pretty much the same regardless of the direction of the
connection.  The only important differences are:

        * When you set up a Controller record, there can only be one
          outgoing connection to a given controller, which means that
          we'd be limited to a single OpenFlow channel for this purpose.
          That might be OK for now but I suspect that we'll want to have
          multiple connections eventually for different purposes or for
          fairness or load balancing.

          On the other hand, ovn-controller can make as many connections
          to OVS as it likes.

        * If ovn-controller connects to OVS, it needs to send a specific
          message to turn on "packet-in"s, instead of getting them by
          default when the connection completes.

There's no real difference regarding keeping the connection up; in
either case that's easy to handle.

It seems a little cleaner to avoid setting up the Controller record,
since there's nothing to clean up on exit in that case and nothing that
an administrator can screw up by modifying the database.

On Wed, Oct 28, 2015 at 05:32:27AM +0530, Babu Shanmugam wrote:
> Hi Ben,
> I understand that when an openflow controller is set on the switch, the
> switch will try to connect to the controller target and keeps alive the
> connection by a series of echo_requests and echo_replies. So, I thought, we
> need a passive connection that listens on the target that is configured for
> the controller and respond to the requests from the switch.
> I also thought this will help in responding to the packet-in requests as
> soon as it arrives. I hope my understanding is correct, if not, please
> correct me.
> 
> Thank you,
> Babu
> 
> On Sunday 25 October 2015 05:02 AM, Ben Pfaff wrote:
> >On Fri, Oct 23, 2015 at 01:12:50PM +0530, Babu Shanmugam wrote:
> >>This patch configures the ovs records for a new controller to br-int
> >>and an endpoint for the new controller
> >>
> >>Signed-off-by: Babu Shanmugam <bschanmu at redhat.com>
> >Doesn't it work to just start a second connection to the controller, in
> >the same way that ofctrl connects to the controller?
> 



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