title: Ping fails in Mininet, RYU - OpenFlow 1.3
body: <p>I am using Mininet, RYU controller and OpenFlow 1.3, to create a topology where host <code>h1</code> is connected to host <code>h2</code> using a switch <code>p0es0</code> in the following way:</p>
  
  <pre><code>h1 h1-eth0:p0es0-eth3
  h2 h2-eth0:p0es0-eth4
  </code></pre>
  
  <p>In my Ryu Controller application, I have the following code snippet to install rules on my <code>p0es0</code> switch to be able to reach h1 from h2 and vice-versa: </p>
  
  <pre><code>    # Install rule to forward packets destined to "10.0.0.2" (h2) via port 3
      ofproto = sw.ofproto        
      match = sw.ofproto_parser.OFPMatch( eth_type = 0x0800, ipv4_dst="10.0.0.1")
      action = sw.ofproto_parser.OFPActionOutput(4)
      inst = [sw.ofproto_parser.OFPInstructionActions(sw.ofproto.OFPIT_APPLY_ACTIONS, [action])]
      mod = sw.ofproto_parser.OFPFlowMod(datapath=sw, match=match,
             instructions=inst, cookie=0, command=ofproto.OFPFC_ADD, idle_timeout=0, 
             hard_timeout=0, priority=100, flags=ofproto.OFPFF_SEND_FLOW_REM)
      sw.send_msg(mod)
  
  
      # Install rule to forward packets destined to "10.0.0.1" (h1) via port 4
      match = sw.ofproto_parser.OFPMatch( eth_type = 0x0800, ipv4_dst="10.0.0.1")
      action = sw.ofproto_parser.OFPActionOutput(4)
      inst = [sw.ofproto_parser.OFPInstructionActions(sw.ofproto.OFPIT_APPLY_ACTIONS, [action])]
      mod = sw.ofproto_parser.OFPFlowMod(datapath=sw, match=match,
             instructions=inst, cookie=0, command=ofproto.OFPFC_ADD, idle_timeout=0, 
             hard_timeout=0, priority=100, flags=ofproto.OFPFF_SEND_FLOW_REM)
      sw.send_msg(mod)
  </code></pre>
  
  <p>My dump-flow command confirms the correct installation of rules in the switch as expected:</p>
  
  <p>*** p0es0 -----------------------------------------------------------------</p>
  
  <p>OFPST_FLOW reply (OF1.3) (xid=0x2):</p>
  
  <p>cookie=0x0, duration=1103.417s, table=0, n_packets=0, n_bytes=0, send_flow_rem priority=100,ip,<strong>nw_dst=10.0.0.2 actions=output:4</strong></p>
  
  <p>cookie=0x0, duration=1103.414s, table=0, n_packets=0, n_bytes=0, send_flow_rem priority=100,ip,<strong>nw_dst=10.0.0.1 actions=output:3</strong></p>
  
  <hr>
  
  <p>However, when I attempt to ping <code>h2</code> from <code>h1</code> or vice-versa, I get Destination Host Unreachable error. I tried using tcpdump on <code>p0es0-eth3</code> -- I see only ARP Request packets. </p>
  
  <p>Am I missing something here? </p>
  
  <p>Thanks.</p>