On the Transition of Legacy Networks to SDN - An Analysis on the Impact of Deployment Time, Number, and Location of Controllers - Diogo Ferreira Thé Pontes; Marcos Fagundes Caetano; Geraldo Pereira Rocha Filho; Lisandro Zambenedetti Granville; Marcelo Antonio Marotta (17th IFIP/IEEE International Symposium on Integrated Network Management, IM 2021, Bordeaux, France, May 17-21, 2021, 2021)