Automation and APIs

OpenFlow

Also called flow table, flow entry, match and action, Open vSwitch, OVS, southbound protocol, TCP 6653, table-miss, fail mode secure

The protocol an SDN controller uses to write match-and-action rules (flows) into a switch's flow table.

A flow matches header fields (ports, MAC and IP addresses, protocol, TCP ports, the target of an ARP request) and says what to do: send out of a port, drop, rewrite, or hand to the controller. The highest priority match wins; a table-miss flow (priority 0) catches the rest. The controller connects over TCP 6653. A switch in fail mode secure forwards only by its flows, even with no controller; in standalone it falls back to learning like an ordinary switch. Open vSwitch is the common software OpenFlow switch.

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