P4 programs specify how a switch processes packets.
P4 is suitable for describing everything from high- performance forwarding ASICs to software switches.
P4 allows network engineers to change the way their switches process packets after they are deployed.
table routing { key = { ipv4.dstAddr : lpm; } actions = { drop; route; } size : 2048; } control ingress() { apply { routing.apply(); } }