<div dir="ltr"><div class="gmail_default" style="font-family:garamond,serif">Yes, indeed the forwarding strategy is the most important but I just want to test the performance of open vswitch on Planetlab nodes.<br>So, for starting I am using the l2 learning component.<br>
</div><div class="gmail_default" style="font-family:garamond,serif">But isn't it true that the extra RTT delay that I see at the first ping packet is because of going first to the controller ?<br></div></div><div class="gmail_extra">
<br><br><div class="gmail_quote">2013/7/31 Murphy McCauley <span dir="ltr"><<a href="mailto:murphy.mccauley@gmail.com" target="_blank">murphy.mccauley@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">Answers inline.<div><br><div><div class="im"><div>On Jul 30, 2013, at 9:44 AM, Kouvakas Alexandros wrote:</div><br><blockquote type="cite"><div dir="ltr"><div class="gmail_default" style="font-family:garamond,serif">
Pretty nice with this module.</div><div class="gmail_default" style="font-family:garamond,serif">I would like to ask some more questions. First, where can I find some explanation for each parameter for example for FlowStatsReceived or for PortStatsReceived ?</div>
</div></blockquote><div><br></div></div><div>I think most of the relevant info should be in the OpenFlow spec. These events more or less correspond to stats replies of the respective types. The only thing POX really does beyond what's in the spec is potentially collecting several individual stats replies and turning them into a single event, which is just to simplify life for people writing controller code a bit (according to the spec, a switch can split a reply across several messages, but in practice this is annoying to deal with).</div>
<div class="im"><br><blockquote type="cite"><div dir="ltr">
<div class="gmail_default" style="font-family:garamond,serif">Moreover what exactly do we consider as web traffic. As I noticed pings between nodes/VMs are not considered as web traffic.</div></div></blockquote><div><br>
</div></div><div>This just follows from the simple example on the wiki. I didn't want to dump all the flows on the console -- I wanted to do something a tiny bit more interesting. So if you look at the example on the wiki, you can see that it goes through each returned flow and just adds up the bytes used for every flow that has a transport protocol source or destination of 80 (line 9 on the wiki; there's a similar line in the expanded example). It's worth noting that there's no actual check that it's TCP, so this could also be UDP port 80, or ICMP with a type or code of 80. This is a bug. :)</div>
<div class="im"><br><blockquote type="cite"><div dir="ltr"><div class="gmail_default" style="font-family:garamond,serif">Finally, is there any method by using POX modules, to measure the time that a packet needs to travel from the source to the destination including the way pass from the controller.</div>
<div class="gmail_default" style="font-family:garamond,serif">For example, when the flow table is empty and I ping from one node to another the first packet needs at least the double time than all the other packets that follow. That means that the first packet "passes" from the controller. So in my case I want to measure these parameters comparing for example to the size of the network. Also I will differenciate the size of the packets to study how the controller reacts in such cases.</div>
</div></blockquote><div><br></div></div><div>I don't have any particular input here, though this or similar problems have been discussed before on the nox-dev mailing list and probably elsewhere (openflow-discuss?), so you might check the list archives.</div>
<div><br></div><div>I will point out that your example where the first packet goes to the controller isn't really fundamental and depends on how you're doing forwarding. Almost all of the POX example forwarding components have different behaviors in this respect -- perhaps most dramatically, the l2_nx_self_learning and topo_proactive components which really don't behave like this at all (in both cases, almost no packets ever go to the controller). And components like those are probably the most realistic.</div>
<span class="HOEnZb"><font color="#888888"><div><br></div><div>-- Murphy</div></font></span><div><div class="h5"><br><blockquote type="cite"><div dir="ltr">
<div class="gmail_default" style="font-family:garamond,serif">2013/7/29 Murphy McCauley <span dir="ltr"><<a href="mailto:murphy.mccauley@gmail.com" target="_blank">murphy.mccauley@gmail.com</a>></span></div></div><div class="gmail_extra">
<div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">That example is meant to be run from the POX CLI/interpreter (that is, it expects you ran the "py" component), not as a standalone component.<div><br></div><div>You could turn it into a component with a little work (it has already been discussed on the mailing list). However, there's a "Statistics Collector Example" in the "Third Party" section of the manual wiki which has already done this (and expanded on the original a bit).</div>
<div><br></div><div>Hope that helps.</div><span><font color="#888888"><div><br></div></font></span><div><span><font color="#888888">-- Murphy</font></span><div><div><br><div><br><div>
<div>On Jul 29, 2013, at 9:26 AM, Kouvakas Alexandros wrote:</div><br><blockquote type="cite"><div dir="ltr"><div><div class="gmail_default" style="font-family:garamond,serif">Hello,<br></div><div class="gmail_default" style="font-family:garamond,serif">
I am trying to collect statistics from the ovs. I tried to run the Example - Web flow statistics but I get the following error<br>
<br></div><i>[inria_nepi@planetlab2 pox]$ ./pox.py samples.pretty_log forwarding.l2_learning flow-stats<br>POX 0.1.0 (betta) / Copyright 2011-2013 James McCauley, et al.<br>Traceback (most recent call last):<br> File "/home/inria_nepi/pox/pox/boot.py", line 89, in do_import2<br>
__import__(name, globals(), locals())<br> File "/home/inria_nepi/pox/ext/flow-stats.py", line 2, in <module><br> log = core.getLogger("WebStats")<br>NameError: name 'core' is not defined<br>
Could not import module: flow-stats</i><br><br></div>I<div class="gmail_default" style="font-family:garamond,serif;display:inline"> am using the betta branch, but I don't think it matters as I get the same error with carp branch.<br>
<br></div><div class="gmail_default" style="font-family:garamond,serif;display:inline">Does anybody knows what happens?<br>Also every suggestion for modules that get statistics from the switch are very welcome.<br><br></div>
<div class="gmail_default" style="font-family:garamond,serif;display:inline">Thanks a lot!</div><h4><br></h4><br>-- <br>Kouvakas Alexandros
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</blockquote></div><br></div></div></div></div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br>Kouvakas Alexandros
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</blockquote></div></div></div><br></div></div></blockquote></div><br><br clear="all"><br>-- <br>Kouvakas Alexandros
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