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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'>Hey Srinivas,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'>I’m an OpenStack newbie but just started working through some of the same questions (experienced folks, please chime in if I’m spurting nonsense here). I’ve found that reading up on Open vSwitch independently has been very helpful, their documentation can be found <a href="http://openvswitch.org/support/">here</a>. Their <a href="http://git.openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=blob_plain;f=FAQ;hb=HEAD">FAQ</a> is quite extensive but is a good read thus far (I’m only about halfway through it).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'>Some of the commands to view flows are well documented in the FAQ:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>Q: Why are there so many different ways to dump flows?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>A: Open vSwitch has two kinds of flows (see the previous question), so<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> it has commands with different purposes for dumping each kind of<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> flow:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> - "ovs-ofctl dump-flows <br>" dumps OpenFlow flows, excluding<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> hidden flows. This is the most commonly useful form of flow<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> dump. (Unlike the other commands, this should work with any<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> OpenFlow switch, not just Open vSwitch.)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> - "ovs-appctl bridge/dump-flows <br>" dumps OpenFlow flows,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> including hidden flows. This is occasionally useful for<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> troubleshooting suspected issues with in-band control.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> - "ovs-dpctl dump-flows [dp]" dumps the datapath flow table<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> entries for a Linux kernel-based datapath. In Open vSwitch<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> 1.10 and later, ovs-vswitchd merges multiple switches into a<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> single datapath, so it will show all the flows on all your<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> kernel-based switches. This command can occasionally be<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> useful for debugging.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> - "ovs-appctl dpif/dump-flows <br>", new in Open vSwitch 1.10,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> dumps datapath flows for only the specified bridge, regardless<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'> of the type.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'>I haven’t gotten to how Open vSwitch populates the flows yet without the use of an SDN controller. I’m a network guy by trade so I imagine there’s some type of learning at layer 2 happening similar to standard Ethernet switching. Can anyone confirm?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'>Thanks,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'>Rob<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:black'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Srinivasreddy R [mailto:srinivasreddy4390@gmail.com] <br><b>Sent:</b> Friday, September 26, 2014 7:19 AM<br><b>To:</b> openstack@lists.openstack.org<br><b>Subject:</b> [Openstack] understanding flows of ovs in openstack<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><div><div><div><div><p class=MsoNormal>hi ,<o:p></o:p></p></div><p class=MsoNormal>i want to understand the role of openvswitch in openstack .<o:p></o:p></p></div><p class=MsoNormal>how and what flows are configured in both compute and networknode . <o:p></o:p></p></div><p class=MsoNormal style='margin-bottom:12.0pt'>please suggest .<o:p></o:p></p></div><p class=MsoNormal style='margin-bottom:12.0pt'>thanks,<br>srinivas.<o:p></o:p></p></div></div></body></html>