ProgrammingSDN1.docx

Programming SDN 1 Problems with programming with POX Programming SDN How to specify the functionality in network applications Net apps: routing, access control, monitoring NAT, TE, etc History solution: ad hoc, by configuring individual routers to achieve the objective SDN promises: new solution based on the global network view provided by the SDN controller. How?? This is a brand new domain!!! It does not help that northbound API is not fixed. Openflow Programming SDN with NOX/POX Event driven programming paradigm Application writer register the events and write the event handlers. API Events: packet_in(switch, port, packet) stats_in (switch, xid, pattern, packets, bytes) flow_removed (switch, pattern, packets, bytes) switch_join(switch) Port_change(switch, port, up) Control and query openflow switches Install(switch, pattern, priority, timeout, actions) uninstall(switch, pattern) Query_stats(switch, pattern) Programming SDN with POX: a repeater application Network app: when the switch is up, install rules for repeater (port 1 to port 2, port 2 to port1) Programming SDN with NOX/POX NOX/POX API is very low level, exposing detailed OpenFlow interface with the forwarding elements install and remove OpenFlow rules on a switch Programming with other controllers is similar, although with different features. SDN controllers expose the switch capability, but do not make programming SDN easier. What is your perfect programming paradigm for SDN? Properties? Issue with NOX programming: components not composable Monitoring capability Ideal solution: if the program is composable Issue with NOX programming: components not composable Pattern priority timeout action count p1 output(p2) p2 output(p1) p2,tp_src(80) Rules can interact: p2,tp_src(80) also matches the rule for p2. The counter will be wrong in this case. Issue with NOX programming Issues with NOX