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.

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