This article surveys several research challenges in interdomain routing. We introduce and describe these challenges in a comprehensible manner, along with a review of the most compelling contributions and ongoing research efforts addressing each of the exposed issues. During this analysis we identify the relation between these research challenges and how they influence each other. We also present our perspectives on why these issues remain largely unsolved, and point out why some of the proposals made so far have not yet been adopted. We hope this can provide some insight on future directions in this complex research area.

In this paper we study the behavior of Internet traffic on the ASlevel topology and discuss its implications on interdomain traffic engineering. We rely on two notable interdomain traffic traces, the first is one month long and the other is one day long. This study shows that interdomain paths are stable for a large majority of the traffic from a routing viewpoint. We show that the aggregation of the traffic occurring on the AS-level graph is essentially limited to direct peers, with almost no aggregation occurring at larger AS hop distances. Furthermore, only part of the AS paths of the AS-level topology that see a lot of traffic are stable, when considering their presence among the largest AS paths on a hourly basis. Relying on the largest AS paths in traffic over a time window to capture the traffic over the next time interval discloses the important variability of the traffic seen by the largest AS paths in traffic. Interdomain traffic engineering is hence due to be difficult because of the limited traffic aggregation on the AS-level topology and the important topological variability of the traffic for a significant percentage of the total traffic.

Abstract-Today, most IP networks are still configured manually on a router-by-router basis. This is error-prone and often leads to misconfiguration. In this paper, we describe the Network Configuration Safeguard (NCGuard), a tool that allows the network architect to apply a safer methodology. The first step is to define his design rules. Based on a survey of the networking literature, we classify the most common types of rules in three main patterns: presence, uniqueness and symmetry and provide several examples. The second step is to write a highlevel representation of his network. The third step is to validate the network representation and generate the configuration of each router. This last step is performed automatically by our prototype. Finally, we describe our prototype and apply it to the Abilene network.

To reflect the importance of network technologies, networking courses are now part of the core materials of Computer Science degrees. We report our experience in jointly developing an open-source ebook for the introductory course, and a series of open educational resources for both the introductory and advanced networking courses. These ensure students actively engage with the course materials, through a hands-on approach; and scale to the larger classrooms and limited teaching staff, by leveraging open-source resources and an automated grading platform to provide feedback. We evaluate the impact of these pedagogical innovations by surveying the students, who indicated that these were helpful for them to master the course materials.

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