[pox-dev] Changing the POX component without restarting POX controller

[Windhya Rankothge]

Sorry trouble you again Murphy..

Is there any way that I can trace the packet, so that I can check the
correctness of my algorithms ?

I tried traceroute, but looks like its not working as expected in Mininet


On Wed, May 29, 2013 at 2:13 PM, Windhya Rankothge <windyswsw at gmail.com>wrote:

> Thanks Murphy.. It worked correctly..
>
>
> On Wed, May 29, 2013 at 12:52 PM, Murphy McCauley <
> murphy.mccauley at gmail.com> wrote:
>
>> I'd say the right way to do it is to remove the event listeners set by
>> one component, and then set them up using the other.  l2_multi wasn't
>> really written with this in mind so it'd take a bit of tweaking to make it
>> happen.  If you were really inclined to do so, I think the easiest way
>> would be to add a boolean enable/disable flag to the l2_multi class and to
>> your version of it.  Then have an if statement in
>> l2_multi._handle_ConnectionUp (and your own class's version) that uses the
>> flag to decide whether it should actually call sw.connect().  When you want
>> to switch between components, toggle the enabled flags, then iterate
>> through all active connections, calling disconnect() on the switches of the
>> old component and connect() on the switches of the new component.
>>
>> I think there may be a far, far easier way to go about this, though.  It
>> seems like the only thing you should need to change is _get_path() or
>> _get_raw_path() or _calc_paths().  I'd just swap the function at runtime.
>>  For example, if you put a modified _get_path() in ext/longestpath.py, you
>> could do something like...
>>
>> ./pox.py forwarding.l2_multi openflow.discovery py
>>
>> This will load up l2_multi and then give a Python interpreter.  You can
>> swap the functions from the interpreter...
>> POX> import pox.forwarding.l2_multi as l2m
>> POX> shortest = l2m._get_path
>> POX> import ext.longestpath
>> POX> l2m._get_path = ext.longestpath._get_path
>>
>> You can switch back to shortest again by doing:
>> POX> l2m._get_path = shortest
>>
>> When you switch, you'll have to wait for existing flows to time out, or
>> send a flow_mod to each connection to delete them (iterate over
>> core.openflow.connections).  You might want to wrap that and the other
>> commands above into a quick little toggle function, which you could then
>> add to the interactive prompt.  The component would looks something like:
>>
>> import pox.forwarding.l2_multi as l2m
>>
>> _orig_get_path = l2m._get_path
>>
>> def _my_get_path (...):
>>   ...
>>   Your longest path code here
>>   ...
>>
>> def toggle ():
>>   if l2m._get_path is _orig_get_path:
>>     l2m._get_path = _my_get_path
>>   else:
>>     l2m._get_path = _orig_get_path
>>
>> def launch ():
>>   core.Interactive.variables['toggle'] = toggle
>>
>> Then you can just do toggle() from the POX prompt to switch.
>>
>> Hope that helps.
>>
>> (Excuse bugs in the above code; none of it is tested.)
>>
>> -- Murphy
>>
>> On May 29, 2013, at 3:13 AM, Windhya Rankothge wrote:
>>
>> >
>> > Hi,
>> >
>> > I am soory if this is a stupid question, but I am new to POX and even
>> though i searched in internet i could not find an answer..
>> >
>> > I am using two component files : l2_multi.py component which will send
>> traffic using shortest path.. and l2_multi_edited.py which will send
>> traffic using longest path..
>> >
>> > I create a topoligy in mininet and start the POX with l2_multi.py
>> component which will send traffic using shortest path..
>> >
>> > after sometime I want to change the componet to l2_multi_edited.py
>> without restarting POX, so that  traffic will be send with longest path..
>> >
>> > how can I do this ? Please be kind enough to help me
>> >
>> >
>> > Best Regards,
>> >
>> > Windhya Rankothge....
>>
>>
>
>
> --
> Best Regards,
>
> Windhya Rankothge..... (WINDY)
>



-- 
Best Regards,

Windhya Rankothge..... (WINDY)
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