[pox-dev] Installing SPF in Switches

[Murphy McCauley]

Have you taken a look at the l2_multi and topo_proactive components?  Both of them compute and install shortest paths.

-- Murphy

On Nov 11, 2013, at 9:48 PM, Muhammad Furqan Gagan <furqan.gagan at gmail.com> wrote:

> Hello …
> 
> I am working on a controller which calculate shrtest path from a function i have made and returns an array of switches in between source and destination switches... When a packet is received i calculate their source and dpids and calculate their shotest path. for example: for switch 1 and switch 7 there is a shortest path [2,3,4,7]
> Now i want to install flows for them 
> 
> 
> Currently I am doing this… It is sending the packet and installing flows but I cant ping … I am new to POX so if you can explain it in bit easier way !! Thanks
> 
> 
> def _handle_PacketIn (self, event):
> 
>         def flood(): #floods the packet
>            
>             msg = of.ofp_packet_out() 
>             msg.actions.append(of.ofp_action_output(port = of.OFPP_FLOOD))
>             msg.data = packet_in.data 
>             msg.in_port = in_port
>             self.connection.send(msg)
> 
>             
>         def drop():# drops the message
>          
>             if packet_in.buffer_id is not None: 
> 
>                 msg = of.ofp_packet_out()
>                 msg.buffer_id = packet_in.buffer_id
>                     
>                 msg.in_port = in_port 
>                 self.connection.send(msg)
> 
> 
>              
>         packet = event.parsed 
>         packet_in = event.ofp 
>         in_port = event.port
>         #print in_port
>         dpid = event.dpid
>        
>         
>         
>         if packet.type == packet.LLDP_TYPE:
>             self.receive_topology_packet(dpid,in_port,packet)
> 
>             return
>         
>             
>             
>         self.host_table[packet.src] = in_port
>         
> 
>         if packet.dst.is_multicast:
>             flood()
>             return
>                    
>         if packet.dst not in self.host_table: # check for unknown destination
>         
>             flood()
>             return
>         
>         else:
>             
>             print "%s" %(packet.src)
>             print "%s" %(packet.dst)
>             p_s = str(packet.src)
>             p_d = str(packet.dst)
>           
>             dpid_src = dpid
>             print "src dpid",dpid_src
>             for s in range(len(switch)):
> 
>                     
>                 if p_d[-1:] == str(switch[s]):
>                     dpid_dst = switch[s]
>                     print "dest dpid",dpid_dst
> 
>             best_route = []
>             best_route = spf.shortest_path(dpid_src,dpid_dst)
>             best_route.reverse()
>             print best_route
>         
>             print " known"
>             
> 
>             msg = of.ofp_flow_mod()
> 
>             if not packet.type == packet.VLAN_TYPE:
>                 print "attaching a vlan id"
>                 msg.actions.append(of.ofp_action_vlan_vid(vlan_vid = dpid_dst))
> 
>             elif dpid_src == dpid_dst:
>                     print "arived at destination striping vtag"
>                     msg.actions.append(of.ofp_action_strip_vlan())                                                                                                                                              
> 
>               
>             if best_route:
>                 if not best_route[0] == dpid_dst:
>                     next_hop = best_route[0]
>                 
> 
>                     if not dpid_src== dpid_dst:
>                         for p in topo[dpid_src]:
>                             temp = topo[dpid_src][p]
>                             if temp [0]== next_hop:   # in topo[dpid_src][p]:
>                                 print"yes"
>                                 print"p",p
>                                             #dp,op = topo[dpid][p]
>                                 op = p
>                                 print "outport",op
>                 else:
>                     print"we r at destination"
>                     op = self.host_table[packet.dst]
>                     print "op"
> 
>           
>                 print"sending flow"                      
>                 msg = of.ofp_flow_mod()  # installing flow
>                 msg.match = of.ofp_match.from_packet(packet, in_port)
>                 msg.idle_timeout = 10
>                 msg.hard_timeout = 30
>                            
>                 msg.actions.append(of.ofp_action_output(port = op))
>                 msg.data = packet_in
>                     
>                 self.connection.send(msg)
>                 
>                 msg = of.ofp_packet_out() 
>                 msg.actions.append(of.ofp_action_output(port = op))
>                 msg.data = packet_in.data 
>                 msg.in_port = in_port
>                 self.connection.send(msg)
>                 print "flow sent"

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