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measure the jitter of odl controller

asked 2015-02-10 07:25:07 -0700

buddah gravatar image

Hi there, i have been making some captures in wireshark, and i understand the protocol( i think), and now i would like to measure the jitter of the odl controller. In other words would like to measure the time that is when i push the flow in the controller and its available in the switch to be used. Can i measure that in a capture in wireshark?. I see the opt flow mod packet but how can i measure this time i talked before? thanks

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answered 2015-02-10 09:28:16 -0700

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updated 2015-02-11 09:59:45 -0700

If you are pushing the flow via REST you can setup tcpdump/wireshark on the ODL controller(or the Switch) see when the packet with the REST information was received and then measure the time till you see the flow_mod packet.

[OpenFlow Switch]                  Issue REST to ODL
      |  <10ms>
[OpenDayLight Controller]          Gets the REST
      |  <2ms>                     Process the REST
[OpenDayLight Controller]          Create and Sends out the Flow
      |  <10ms>
[OpenFlow Switch]                  See Flow Mode 
      | <1ms>                      Flow is ready to be used.
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Thanks all for your answers Chris O'Shea and jamoluhrsen...just a doubt i already see the cenario you post Chris, but i think its better to measure from the Rest information received till the ACK tcp packet that the switch send after receiving the FlowMod Packet? what you think? or just like you said till the Flow_Mod Packet? I know the difference of time is minimum, but i what is really the right time ( that is available in the switch to be used), flow mod packet or the ack tcp packet of flow mod? Thanks a lot, for your patience. Regards

buddah ( 2015-02-13 07:39:24 -0700 )edit

I would say the ack is a good start. There other things to worry about but it's a good start.

Chris O'Shea ( 2015-02-13 11:42:33 -0700 )edit

yes...what other things Chris? So i can understand better. thanks for all once more, sorry to disturb you

buddah ( 2015-02-16 01:43:33 -0700 )edit

in theory the ack is just saying yes i got the packet, not that yes i have processed the packet, but we're talking less than a ms. what you need is some sort of hook into the dataplane of the switch to signal that the flow been process and accepted.

Chris O'Shea ( 2015-02-16 09:03:33 -0700 )edit

yes i understand that, for saying that received doesn't mean that is processed and ready to be used. But well, i think there is no way i can measure the real jitter of the controller, because there is no information in terms of packets, that tells me the flow is ready to be used, thanks once more Chris

buddah ( 2015-02-17 03:50:55 -0700 )edit
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answered 2015-02-10 09:54:28 -0700

buddah gravatar image

thanks a lot, Chris. Well ..i'm pushing via Gui, i'm making the capture in the openvswitch, but like you said, i have to make the capture in the Controller, and when i see the flow mod packet in the controller it's available in the switch right?

Thanks for all

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Almost the switch needs to get the message, so the switch could be less that 1ms away or like 200ms away.

Chris O'Shea ( 2015-02-10 18:07:41 -0700 )edit

let's see if i understand, it's not possible to measure the time between the pushing flow in the controller and the when it becomes available in the switch? i have to make the capture in the controller?. Sorry chris for my doubts, and misunderstanding, and thanks for your support .

buddah ( 2015-02-11 01:14:44 -0700 )edit

So i have edited my answer with the basic workflow of adding a flow with a switch and some 'SAMPLE' times, there lots of variables that could impact your testing.

Chris O'Shea ( 2015-02-11 10:06:44 -0700 )edit

To add to Chris' points. I believe to push a flow via GUI, it will in turn make a REST call behind the scenes. Assuming this, do the packet capture in/out on the ODL controller using the times between the flow request IN and flow_mod OUT. that eliminates the switch and network from the equation.

jamoluhrsen ( 2015-02-11 21:29:02 -0700 )edit
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Asked: 2015-02-10 07:25:07 -0700

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Last updated: Feb 11 '15