Re: [pox-dev] How to get switch name set in Mininet in POX
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? 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 '0001'. On Tue, Oct 29, 2013 at 8:14 PM, Murphy McCauley murphy.mccau...@gmail.comwrote: 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
Re: [pox-dev] How to get switch name set in Mininet in POX
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 '0001'. 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
Re: [pox-dev] How to get switch name set in Mininet in POX
Thanks for the clarification. On Tue, Oct 29, 2013 at 8:31 PM, Murphy McCauley murphy.mccau...@gmail.comwrote: 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 '0001'. 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
