I am trying to pause an OVS with POX as described in
http://www.openvswitch.org/support/dist-docs/ovs-ofctl.8.txt
The respective add-flow command is (thanks to pchaigno for his answer):
sudo ovs-ofctl add-flow c2 "dl_dst=00:00:00:00:00:01,actions=controller(pause)"
(switch name c2)
But, I cannot find in the POX documentation a way of sending such command to the switch.