Yes, it's possible. Insert a flow in the switch that matches whatever packet you're interested in. The action for this flow should be to send to controller (output to the OFPP_CONTROLLER virtual port). Then in your packet_in handler on the controller, you have to check to see if you get such a packet. When you do, send back a packet_out.
Off the top of my head, I think the discovery component should do both of those things (install a flow with send-to-controller and sending packets) if you want an example. -- Murphy On Apr 25, 2012, at 12:02 PM, Weiyang Mo wrote: > Thanks very much for your quick reply. > > But I am still confused. do you mean that "the controller instruct a switch > to send a packet" is not an OpenFlow feature? Or I misunderstand what you > mean. > > I am sending packets from a client to a server through multiple OpenFlow > switches. I already have this functionality that the controller inserts > flow-entries and then the packets can be sent to the server. > > Now, I want to have another action that " when the controller receives the > first packet-in message, it can instruct a switch to send a packet which > contains some data(e.g, hello). And this new packet can be sent to another > host. If so, the host can run other applications automatically upon receving > the packet "hello". > > Is it possible?( Packet in->controller controller-> instrucrt the > switch to create a new packet new packet(Hello) ->host). How should I > write the pseudo code. > > Thanks > > Weiyang > > 2012/4/25 Murphy McCauley <[email protected]> > There are no examples of this because this is not an OpenFlow feature -- only > the controller can instruct a switch to send a packet. > > Unless maybe there is some vendor extension for some switches… > > -- Murphy > > On Apr 25, 2012, at 11:28 AM, Weiyang Mo wrote: > >> BTW,any example code for this? For instance, the controller wishes to send a >> packet which contains the data "Hello" through the switch to the Output. >> >> How should I write the code? Is it like "actions=[openflow.ofp_packet_out, >> ...]" ? >> >> I am not clear because I don't find sample codes. Could anyone provides a >> simple sample code? >> >> Regards >> >> Weiyang >> ---------- Forwarded message ---------- >> From: Weiyang Mo <[email protected]> >> Date: 2012/4/25 >> Subject: instruct the swtich to create a new packet. >> To: [email protected] >> >> >> Hi,all, >> >> I want to insert an action in to flow entry. The action can tell the switch >> to create a new arbitary packet. What command should I use? >> >> Thanks a lot >> >> Weiyang >> > >
