The equal deepest vertex first reboot: Rebooting network edge switches in a campus network

Even in the era of Software Defined Network (SDN) or Software Defined Infrastructure (SDI), network edge switches still require to be rebooted for some reasons, e.g., updating a firmware, configuring a special behavior and so on. It may be necessary to clarify how one can shorten downtime of a campus network when many switches in the network require reboots. To this end, this paper proposes the equal deepest vertex first reboot with vertex contraction that can simultaneously reboot many network switches with less overhead downtime. This paper tries to express a campus network in a graph theory fashion, reduce downtime overhead by vertex contraction, and proves that all switches can be rebooted within a finite number of rebooting procedures. This paper presents an implementation of the proposed procedures, and evaluates the proposed method in an actual campus network. The equal deepest vertex first reboot with vertex contraction has appeared to reboot all switches by only 16-second additional overhead out of 109-second downtime in total where the ideal minimum downtime was 93 seconds in an actual campus network where there were more than 300 network switches installed.