On Oct 29, 2013, at 5:23 PM, Sulabh Bista <sul...@gmail.com> wrote: > Thanks Murphy. That helped. > > I noticed (with the dpctl show command in Mininet CLI) that two switches s1 > and r1 have the same DPID. Should DPID be unique or is this behaviour ok?
Nope, not okay. They're supposed to be unique and it says so in the spec. > I checked the source where dpid is being generated automatically and it shows > that the dpid is derived from the number in the switch's name. So, s1 and r1 > has the same dpid '0000000000000001'. Yeah. It's convenient to have them match up when it works out nicely (e.g., when all your switches are named s*). When it doesn't work out nicely, it's just wrong. You should override the default DPID selection. (And Mininet should really refuse to do this in the first place!) -- Murphy > On Tue, Oct 29, 2013 at 8:14 PM, Murphy McCauley <murphy.mccau...@gmail.com> > wrote: > I don't think that switch name is communicated in a particularly direct way > over OpenFlow. That is, I don't think it's set as one of the fields in the > switch stats or anything. However, you can take advantage of the fact that > this name is used as the name of the "internal" port on the switch, since > port names are communicated from switch to controller. Each OpenFlow > Connection object attempts to keep track of the ports, so you just need to > check the name of the internal port. Try "print > event.connection.ports[of.OFPP_LOCAL].name" in your packet handler. > > There may be configurations where this doesn't work, but one doesn't > immediately come to mind (at least for OVS). > > For what it's worth, it's usually better to track switches by their DPID > rather than a name. > > -- Murphy > > On Oct 29, 2013, at 4:55 PM, Sulabh Bista <sul...@gmail.com> wrote: > > > Hello: > > > > I wanted to know if we can fetch the name assigned to an OVSwitch in > > Mininet in POX. I am listening to PacketIn event and found noting relating > > to the switch name in the 'event' object. > > > > I am new to all of this. Sorry if my question sounds too dumb. > > > > Regards, > > Sulabh Bista > >
