The INTERNATIONAL TELETRAFFIC CONGRESS ITC 31, to be held August 27-29, 2019 at the Budapest University of Technology and Economics, Hungary, is the 31st edition of this international flagship congress in the field of networking science and practice. ITC was founded back in 1955 by enthusiastic scientists and engineers who were willing to deploy networks in a holistic way. Since then, it has established a multi-decade tradition as the primary forum for presenting and discussing the latest technical advances in the broad areas of teletraffic models, network systems, and measurements.