[pox-dev] Flow rule installation using POX

[Murphy McCauley]

You are just creating a message, but that's not enough -- you have to send
it to a switch.  This section of the POX manual may be of help:
https://noxrepo.github.io/pox-doc/html/#communicating-with-datapaths-switches

You also might take a look at some of the sample POX components,
particularly ones in the forwarding/ directory.

But I think you've got bigger problems.  By default, POX actually clears
the tables on switches when they connect -- sending a command much like the
one you've constructed.  So I think switches aren't connecting to POX.
Depending on what version of POX you're running, one possibility is that
POX's OpenFlow component isn't running.  You might look at the
documentation for the of_01 component in the manual:
https://noxrepo.github.io/pox-doc/html/#openflow-of-01

The manual mentions that POX will generally automatically load the of_01
(OpenFlow 1.0) component if another component that uses OpenFlow is
loaded.  Since you're entering stuff in the CLI, maybe you aren't loading
any OpenFlow-using component?  In that case, you'll need to launch of_01
manually.  If you're just running POX without any commandline arguments at
all, you should probably read:
https://noxrepo.github.io/pox-doc/html/#invoking-pox

Ultimately, you should see some log messages in POX about the switches
connecting.  Are you?

Not really related to the above, but you mention how packets being dropped
means the table entry is still there.  That's not true, generally
speaking.  In general, an OpenFlow switch without any table entries doesn't
forward any traffic (though it may encapsulate at least the headers and
send it to the controller).

-- Murphy

On Wed, Mar 13, 2019 at 8:36 PM Sukheja, Himanshu <hxs376 at psu.edu> wrote:

>  have created a simple topology using Mininet in which I have created a
> single switch and connected it to a remote controller (POX). I installed a
> simple flow rule using Mininet CLI which commands the switch to drop all
> packets.
>
> sh ovs-ofctl add-flow s1 priority=40000,hard_timeout=30,actions=drop
>
> Now In POX CLI I run the following command
>
> msg = of.ofp_flow_mod(command=of.OFPFC_DELETE)
>
> Although now when I do a Dump-flow command on mininet terminal it still
> shows the flow is installed
> Also, I tried to ping h1 and h2, and the packets are being dropped (which
> means that the flow is still there)
>
>
> Could you please point out the error in my execution here.
>
> Thanks
> ***********************************************
> ************************************************************************
> Himanshu Sukheja
>
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