Correct.

-- Murphy

On Mar 30, 2012, at 5:53 PM, Vishal wrote:

> Hi Murphy,
> 
> Thanks a lot,
> 
> Does that basically means:
> 
> actions = [[openflow.OFPAT_OUTPUT, [0, openflow.OFPP_IN_PORT]]]
> 
> Regards,
> Vishal
> 
> 
> On Fri, Mar 30, 2012 at 8:19 PM, Murphy McCauley <[email protected]> 
> wrote:
> Specifically in order to avoid creating loops, an output action will 
> generally not go back out of the incoming port.  If you do really want to do 
> this, you must add an output action that outputs to the OFPP_IN_PORT virtual 
> port.  If you check the spec, it describes OFPP_IN_PORT as "Send the packet 
> out the input port.  This virtual port must be explicitly used in order to 
> send back out of the input port."
> 
> -- Murphy
> 
> On Mar 30, 2012, at 5:09 PM, Vishal wrote:
> 
> > Hi,
> >
> > I have 2 openvswitches: OVS1 and OVS2
> >
> > OVS1,  port 3 is connected to OVS2's port 3
> >
> > so, I set up a rule, saying traffic_matching_some_condition, when received 
> > on port 3 send it back to port 3 (for both the switches, in pyswitch, 
> > handle packet in).
> >
> > The above should in theory, cause a packet to ping pong between the two 
> > interfaces until the hard time out. --> essentially, it's forcibly creating 
> > a loop.
> >
> >
> > I achieve this by setting -> out_port = 3 (instead of prt[0] for the 
> > matching flow) in pyswitch.
> > actions = [[openflow.OFPAT_OUTPUT, [0, out_port]]]
> >             inst.install_datapath_flow(dpid, flow, CACHE_TIMEOUT, 
> > openflow.OFP_FLOW_PERMANENT,
> >                                 actions, bufid, 
> > openflow.OFP_DEFAULT_PRIORITY, inport, buf)
> >
> >
> > When I look at Flow Mod for this flow, it correctly sets the port to 3.
> >
> > The problem is that the actual  packet is not being sent by the switch back 
> > to the port on which it was received.
> >
> > On wireshark, I see that number of packets on each switch is same as number 
> > of packets generated by one client host connected to one of the switches.
> >
> > Is there a mechanism to prevent such looping in the openv switch or am i 
> > doing something wrong ?
> >
> > Regards,
> > Vishal
> 
> 

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