PPCU: Proportional per-packet consistent updates for Software Defined Networks

Per-packet consistency (PPC) is preserved, if during an update to a Software Defined Network (SDN), every packet either matches the new rules added or the old rules to be deleted, but not a combination of both. We propose a general update algorithm called PPCU that preserves PPC, is concurrent and provides an all-or-nothing semantics for an update, irrespective of the execution speeds of switches and links, while confining changes to only the affected switches and affected rules.