On Sat, Apr 23, 2016 at 11:45:12AM -0700, Ben Warren wrote: > Thanks for the explanations! > > On Apr 23, 2016, at 10:15 AM, Ben Pfaff <b...@ovn.org> wrote: > > > > On Fri, Apr 22, 2016 at 11:25:26PM -0700, Ben Warren wrote: > >> As you can see, the disconnects happen when the datapath ID changes, > >> presumably due to adding interfaces? Only the addition of the first > >> two interfaces seem to bring it down. > > > > OVS disconnects OpenFlow connections when the datapath ID changes > > because the datapath ID is important to some controllers and OpenFlow > > provides no way for a switch to notify a controller that the datapath ID > > has changed. > > > OK, so what causes the datapath ID to change (Linux kernel 3.10 > datapath in this case)? Does it come from the kernel or is it an OVS > thing?
The datapath ID is an OpenFlow concept, and there's no connection to the OVS concept of a "datapath", so the datapath in use doesn't matter. By default, Open vSwitch uses the lowest-numbered Ethernet address of any of the physical ports connected to a bridge as the bridge's datapath ID. You can override this with other-config:datapath-id, as documented, but otherwise if the ports in the bridge change the datapath ID may change as well. > >> On the client side, I’m really confused. As you can see, I re-open > >> the connection with a HELLO message, and the HELLO response comes back > >> with an earlier XID (0x80 vs. the expected 0x86). Message 0x83 was a > >> BARRIER response, and a valid BARRIER reply was received, so it would > >> seem that messages after 0x80 were accepted: > > > > HELLO is not a request/response message. Rather, both sides of the > > OpenFlow connection send a hello message at the initiation of the > > connection. Each side chooses its own xid as it wishes, so one cannot > > expect the xids to match. The xid for a hello message is only > > significant for sending an OFPT_ERROR response, if necessary. > > OK, is this understanding correct: for send/receive (GetConfig, > Feature etc.) messages ovs-vswitchd will mirror back the XID of the > request, OpenFlow requires that behavior. > but for HELLO it keeps a static monotonically increasing counter? That's the current implementation but there's certainly no guarantee that it won't change. _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
