In multi-domain software defined networks

the existed switch migration strategies always have big computation space and only consider single migration factor.Once the controller gets broken

the switches cannot be migrated immediately.This paper presents the controller hot backup and election problem and designs the corresponding algorithms to find the backup space and complete the master controller election.To reasonably build the network

this paper considers the message exchange cost

the disconnectivity cost

load imbalance cost and cross domain cost.Results show that

compared with the existed algorithms

the proposed algorithms reduce the controller backup space by an average of 65%

and increase the weighted comprehensive evaluation up to 71% in OS3E topology.