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—Network operators invest significant resources in monitoring and troubleshooting the infrastructure they run. Currently, the availability of large networks of probing devices, like, for example, RIPE Atlas, dramatically increases the amount of data an operator can rely on. In particular, the large amount of traceroutes they can produce are both an opportunity and a challenge. In this paper we provide a detailed description of RoutingWatch, a visual tool for interactively performing searches and analysis of routing events inferred from a large set of traceroutes. The key design choices of RoutingWatch are based on discussions with network operators. We evaluate the effectiveness of our approach by conducting a preliminary user study.

Bitcoin is a digital currency whose transactions are stored into a public ledger, called blockchain, that can be viewed as a directed graph with more than 70 million nodes, where each node represents a transaction and each edge represents Bitcoins flowing from one transaction to another one. We describe a system for the visual analysis of how and when a flow of Bitcoins mixes with other flows in the transaction graph. Such a system relies on high-level metaphors for the representation of the graph and the size and characteristics of transactions, allowing for high level analysis of big portions of it.

Compliance with the Gao-Rexford conditions [1] is perhaps the most realistic explanation of Internet routing stability, although BGP is renowned to be prone to oscillations. Informally, the Gao-Rexford conditions assume that (i) the business relationships between Internet Service Providers (ISPs) yield a hierarchy, (ii) each ISP behaves in a rational way, i.e., it does not offer transit to other ISPs for free, and (iii) each ISP ranks routes through customers better than routes through providers and peers.

For an Internet Service Provider (ISP), the knowledge of which interdomain paths could be traversed by its BGP announcements - and thus traffic flows - is essential to predict the impact of network faults, to develop effective traffic engineering and peering strategies, and to assess the quality of upstream providers. However, current methodologies do not provide this information. We present methodologies to discover how the BGP announcements for an ISP’s prefix are propagated through the Internet using withdrawals and specially crafted AS-sets. The techniques allow an ISP to determine which paths could be traversed in the presence of network faults or different routing policies on the ISP’s part and to deduce the routing policies of other ISPs with respect to its network. We validate our techniques through experimentation in the IPv6 and IPv4 Internet, showing that they can be safely and effectively applied in real-world situations.

Tunnels are widely used to improve security and to expand networks without having to deploy native infrastructure, and play an important role in the migration to IPv6. In this paper we introduce a number of techniques to detect, and collect information about, IPv6-in-IPv4 tunnels. We also show how, once a tunnel has been discovered, it can be used as a "vantage point" to launch third-party tunnel-discovery explorations, scaling up the discovery process. We describe the Tunneltrace tool which implements the proposed techniques, and validate them by means of a wide experimentation on the 6bone tunneled network, on the Italian Academic and Research network, and through the test boxes deployed worldwide by the RIPE NCC as part of the Test Traffic Measurements Service. We assess to what extent 6bone registry information is coherent with the actual network topology, and we provide the first experimental results on the current distribution of IPv6-in-IPv4 tunnels in the Internet, showing that tunnels are very common: even the "native" networks we tested reach more than 60% of all IPv6 prefixes through tunnels.

The problem of computing the types of the relationships between Internet autonomous systems is investigated. We refer to the model introduced in (ref.1), (ref.2) that bases the discovery of such relationships on the analysis of the AS paths extracted from the BGP routing tables. We characterize the time complexity of the above problem, showing both NP-completeness results and efficient algorithms for solving specific cases. Motivated by the hardness of the general problem, we propose heuristics based on a novel paradigm and show their effectiveness against publicly available data sets. The experiments put in evidence that our heuristics performs significantly better than state of the art heuristics.