On the Update Problems for Software Defined Networks

Abstract

The designing of network update algorithms is urgent for the development of SDN control software. A particular case of Network Update Problem is that of restoring seamlessly a given network configuration after some packet forwarding rules have been disabled (say, at the expiry of their time-outs). We study this problem in the framework of a formal model of SDN, develop correct and safe network recovering algorithms, and show that in general case there is no way to restore network configuration seamlessly without referring to priorities of packet forwarding rules.

Keywords

• software defined network
• switch
• controller
• forwarding rule
• packet
• network update
• route
• post-condition
• invariant