Thanks for the clarification.
On Tue, Oct 29, 2013 at 8:31 PM, Murphy McCauley <murphy.mccau...@gmail.com>wrote: > 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 >> >> > >
