Hello Murphy:
Thanks for your replying. I'm using OVS1.9 integrated with OpenFlow 1.2, and the tool for dumping flow entries is ovs-ofctl dump-flows. I did some test again, and it's so strange that the back flow for ssh connection needs the field of nw_tos=16. If the field for nw_tos equals to 0, the flow can't match correctly. Just like below 1. The back flow which nw_tos equals to 0, the flow can't match. cookie=0x0, duration=4.184s, 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=c8:be:19:49:d7:d2,nw_src=192.168.15.110,nw_dst=192.168.15.197, nw_tos=0,tp_src=22,tp_dst=55162 actions=mod_dl_src:c8:be:19:49:d7:d1,output:46 2. 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 3. The back flow which nw_tos equals to 16, the flow can match successfully. cookie=0x0, duration=4.153s, table=0, n_packets=4, n_bytes=468, 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, nw_tos=16,tp_src=22,tp_dst=55162 actions=output:46 Can you got some ideal about this strange flow? And how can I find the flow_mods that correspond to these flows in POX? Thanks again. 2013/5/15 Murphy McCauley <[email protected]> > 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? > > 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. > > -- Murphy > > > On May 15, 2013, at 12:34 AM, chenli wrote: > > Hello everyone: > > > I'm using POX to redirect tcp traffic, it just modify the action output > and destination IP and MAC address. > > But when I modify the code in POX to do tcp flow redirection, I got > confused about the abnormal flows like below: > > The normal redirection flows: > > 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, > nw_tos=0,tp_src=22,tp_dst=55029 > actions=mod_dl_src:c8:be:19:49:d7:d1,output:46 > 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, > nw_tos=0,tp_src=55029,tp_dst=22 > actions=mod_dl_dst:ac:f1:df:79:29:be,output:42 > > On the general case, the tcp traffic will follow the above two flows to do > transmission. > > But the strange thing is POX also add the following two abnormal flows, so > the ssh redirection connection can't connect successfully. > > The abnormal flows: > > 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, > nw_tos=16,tp_src=55029,tp_dst=22 > actions=mod_dl_src:c8:be:19:49:d7:d2,output:42 > 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, > nw_tos=16,tp_src=22,tp_dst=55029 > actions=mod_dl_dst:ac:f1:df:79:29:be,output:42 > > 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? > > Thanks. > > >
