Thursday, January 23, 2014

ovs-ofctl commands on OpenFlow 1.3 Mininet switch (ovsk)

ovs−ofctl program is a command line tool for monitoring and administering OpenFlow switches. It can also show the current state of an OpenFlow switch, including features, configuration, and table entries. It should work with any OpenFlow switch, not just Open vSwitch.

Before pushing the flows we need to start mininet switch. using below command(also shown in snapshot).
sudo mn --topo single,2 --controller remote,ip=192.168.56.103:6653 --switch ovsk,protocols=OpenFlow13
where,
192.168.56.103 is openflowplugin Controllers IP Address and protocols=OpenFlow13 states that we need to use OpenFlow protocol version 1.3, tcp/6653 is used for OF1.3 communication and 6633 for OF1.0.
Point to note here, Mininet and Controller are running on different Virtual Machines.


 If the above command is successfully executed we should see OF1.3 communication between OVSK(switch s1 here) and SDN Controller.
Flows can be added as
sudo ovs-ofctl -O Openflow13 add-flow s1 in_port=1,actions=nw_ttl:2,output:2

sudo ovs-ofctl -O OpenFlow13 add-flow s1 priority=11,dl_type=0x0800,nw_src=10.0.0.1,action=mod_tp_dst:8888

If the above command is successfully configured on OVSK we should successfully dump flows.
mininet@mininet-vm:~$ sudo ovs-ofctl -O OpenFlow13 dump-flows s1
OFPST_FLOW reply (OF1.3) (xid=0x2):
 cookie=0x0, duration=7.443s, table=0, n_packets=0, n_bytes=0, priority=11,ip,nw_src=10.0.0.1 actions=mod_tp_dst:8888


ovs-ofctl connects to an OpenFlow switch using ssl, tcp(ip and port), socket file, unix file etc. ovs-ofctl talks to ovs-vswitchd, and ovs-vsctl talks to ovsdb-server.

Detailed options can be found at
http://openvswitch.org/cgi-bin/ovsman.cgi?page=utilities%2Fovs-ofctl.8