Hello Murphy:<div><br></div><div><br></div><div>Thanks for your replying.</div><div><br></div><div>I'm using OVS1.9 integrated with OpenFlow 1.2, and the tool for dumping flow entries is ovs-ofctl dump-flows.</div><div>
<br></div><div>I did some test again, and it's so strange that the back flow for ssh connection needs the field of nw_tos=16.</div><div><br></div><div>If the field for nw_tos equals to 0, the flow can't match correctly. Just like below</div>
<div><br></div><div>1. The back flow which nw_tos equals to 0, the flow can't match.</div><div><div> cookie=0x0, duration=4.184s, table=0, <font color="#006600">n_packets=0, n_bytes=0</font>, idle_timeout=30, tcp,dl_vlan=0,dl_vlan_pcp=0,dl_src=ac:f1:df:79:29:be,dl_dst=c8:be:19:49:d7:d2,nw_src=192.168.15.110,nw_dst=192.168.15.197,<font color="#006600">nw_tos=0</font>,tp_src=22,tp_dst=55162 actions=mod_dl_src:c8:be:19:49:d7:d1,output:46</div>
<div><br></div><div>2.</div><div> cookie=0x0, duration=4.162s, table=0, n_packets=7, n_bytes=748, idle_timeout=30, tcp,dl_vlan=0,dl_vlan_pcp=0,dl_src=c8:be:19:49:d7:d2,dl_dst=c8:be:19:49:d7:d1,nw_src=192.168.15.197,nw_dst=192.168.15.110,nw_tos=0,tp_src=55162,tp_dst=22 actions=mod_dl_dst:ac:f1:df:79:29:be,output:42</div>
<div><br></div><div>3. The back flow which nw_tos equals to 16, the flow can match successfully.</div><div> cookie=0x0, duration=4.153s, table=0, <font color="#000099">n_packets=4, n_bytes=468</font>, idle_timeout=30, tcp,dl_vlan=0,dl_vlan_pcp=0,dl_src=ac:f1:df:79:29:be,dl_dst=c8:be:19:49:d7:d2,nw_src=192.168.15.110,nw_dst=192.168.15.197,<font color="#000099">nw_tos=16</font>,tp_src=22,tp_dst=55162 actions=output:46</div>
</div><div><br></div><div>Can you got some ideal about this strange flow? And how can I find the flow_mods that correspond to these flows in POX? </div><div><br></div><div>Thanks again.</div><div><br></div><div><br><br><div class="gmail_quote">
2013/5/15 Murphy McCauley <span dir="ltr"><<a href="mailto:murphy.mccauley@gmail.com" target="_blank">murphy.mccauley@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">I'd suggest you start by dumping the control traffic (e.g. with openflow.debug) and looking at it in WireShark. Can you find the flow_mods that correspond to these flows?<div><br></div>
<div>Also, what switches are you using and which tool is displaying these flow table entries? If you're using OVS and any tool besides ovs-ofctl, for example, I'm not sure I'd trust them.</div><span class="HOEnZb"><font color="#888888"><div>
<br></div></font></span><div><span class="HOEnZb"><font color="#888888">-- Murphy</font></span><div><div class="h5"><br><div><br><div><div>On May 15, 2013, at 12:34 AM, chenli wrote:</div><br><blockquote type="cite">Hello everyone:<div>
<br></div><div><br></div><div>I'm using POX to redirect tcp traffic, it just modify the action output and destination IP and MAC address.</div><div><br></div><div>But when I modify the code in POX to do tcp flow redirection, I got confused about the abnormal flows like below:</div>
<div><br></div><div>The normal redirection flows:</div><div><br></div><div><div> cookie=0x0, duration=8.668s, table=0, n_packets=26, n_bytes=2651, idle_timeout=30, tcp,dl_vlan=0,dl_vlan_pcp=0,dl_src=ac:f1:df:79:29:be,dl_dst=c8:be:19:49:d7:d2,nw_src=192.168.15.110,nw_dst=192.168.15.197,<font color="#000099">nw_tos=0</font>,tp_src=22,tp_dst=55029 actions=mod_dl_src:c8:be:19:49:d7:d1,output:46</div>
<div> cookie=0x0, duration=8.652s, table=0, n_packets=33, n_bytes=3363, idle_timeout=30, tcp,dl_vlan=0,dl_vlan_pcp=0,dl_src=c8:be:19:49:d7:d2,dl_dst=c8:be:19:49:d7:d1,nw_src=192.168.15.197,nw_dst=192.168.15.110,<font color="#000099">nw_tos=0</font>,tp_src=55029,tp_dst=22 actions=mod_dl_dst:ac:f1:df:79:29:be,output:42</div>
<div><br></div><div>On the general case, the tcp traffic will follow the above two flows to do transmission.</div><div><br></div><div>But the strange thing is POX also add the following two abnormal flows, so the ssh redirection connection can't connect successfully.</div>
<div><br></div><div>The abnormal flows:</div><div><br></div><div> cookie=0x0, duration=5.105s, table=0, n_packets=0, n_bytes=0, idle_timeout=30, tcp,dl_vlan=0,dl_vlan_pcp=0,dl_src=ac:f1:df:79:29:be,dl_dst=ac:f1:df:79:29:be,nw_src=192.168.15.197,nw_dst=192.168.15.110,<font color="#000099">nw_tos=16</font>,tp_src=55029,tp_dst=22 actions=mod_dl_src:c8:be:19:49:d7:d2,output:42</div>
<div> cookie=0x0, duration=5.091s, table=0, n_packets=19, n_bytes=2218, idle_timeout=30, tcp,dl_vlan=0,dl_vlan_pcp=0,dl_src=ac:f1:df:79:29:be,dl_dst=c8:be:19:49:d7:d2,nw_src=192.168.15.110,nw_dst=192.168.15.197,<font color="#000099">nw_tos=16</font>,tp_src=22,tp_dst=55029 actions=mod_dl_dst:ac:f1:df:79:29:be,output:42</div>
</div><div><br></div><div>I got confused about the nw_tos field for abnormal flows, why it has the value of 16 which is different from the normal redirection flows and POX need to add it?</div><div><br></div><div>Thanks.</div>
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