While the Internet is ubiquitous in most parts of the world today, the dominant network access technology is gradually shifting from wired to wireless connections. Notably, the ever increasing bandwidth, together with reduced latency in mobile networks, enables a multitude of new use cases for a wide range of industries. These new use cases have typically increased quality requirements for the wireless connection. Accordingly, the Internet architecture needs to keep pace with the recent developments, particularly in light of the holistic approach of the new fifth generation (5G) mobile communication standard. In this study, we shed light on the effects of 5G on the Internet's core, i.e., on the Internet interdomain traffic. The interdomain traffic between distinct autonomous systems (ASs) is exchanged by transit networks as well as through peerings at private network interconnects (PNIs) and public Internet Exchange Points (IXPs). 5G interdomain traffic estimation is especially important for IXPs as these are focal points that aggregate high traffic volumes. We coherently derive twelve 5G use case groups and present an overview of their individual associated 5G use cases. We characterize the communication networking (connection) requirements and the resulting implications of these use cases. Further, we develop and apply a methodology to assess the 5G use cases, so as to rank them in terms of their projected impact on the overall internet traffic growth. Based on this systematic approach, we conclude that the traffic for the use case groups Video in 5G, Health, and Virtual & Augmented Reality will have the largest impact. We identify a large number of other use case groups, e.g., Live Events, Tactile Internet, and Manufacturing, that will contribute rather small individual fractions to the overall growth of Internet traffic. However, their aggregated contribution to the internet traffic growth will be significant. Our traffic estimation can inform interdomain infrastructure providers, such as IXPs, and policy makers about the likely impact of the introduction of 5G on the interdomain traffic in the Internet.