A prefix hijack attack involves an attacker announcing victim networks' IP prefixes into the global routing system. As a result, data traffic from portions of the Internet can be diverted to attacker networks. Prefix hijack attacks are a serious security threat in the Internet and it is important to understand the factors that affect the resiliency of victim networks against these attacks. In this paper, we conducted a systematic study to gauge the effectiveness of prefix hijacks launched at different locations in the Internet topology. Our study shows that direct customers of multiple tier-1 networks are the most resilient, even more than the tier-1 networks themselves. Conversely, if these customer networks are used to launch prefix hijacks, they would also be the most effective launching pads for attacks. We verified our results through case studies using real prefix hijack incidents that had occurred in the Internet.

The global Internet routing infrastructure is a large and complex distributed system where routing changes occur constantly. Our objective in this paper is to develop a simple and effective inference solution that can identify the AS or inter-AS link failures that trigger large scale routing changes in near realtime. We achieve this goal through a novel approach based on link weights. We measure the weight of each inter-AS link by the number of routes carried over that link, and keep track of its expected value and variance. We then correlate the weight changes of adjacent links and use a min-cut heuristic to find candidates for the origin of change. This work makes three contributions. First, we keep track of link weights rather than the routes of individual prefixes and thus our analysis is based on an aggregate view. Second, we use expected value and mean deviation of the link weights to identify routing events and distinguish route changes caused by failures from those by recoveries. Finally we use a min-cut heuristic based on the classification of routing events to accurately identify the AS or inter-AS link most likely responsible for the observed route changes. We verified our design using BGP data collected from operational Internet. Our efficient and accurate routing diagnosis solution can greatly help us gain better understanding of the dynamics in the operational Internet.

In this paper we propose a new routing protocol and address scheme, geographically informed inter-domain routing (GIRO). GIRO departs from previous geographic addressing proposals in that it uses geographic information to assist, not to replace, the provider-based IP address allocation and policy-based routing. We show that, by incorporating geographic information into the IP address structure, GIRO can significantly improve the scalability and performance of the global Internet routing system. Within the routing policy constraints, geographic information enables the selection of shortest available routing paths. We evaluate GIRO'S performance through simulations using a Rocketfuel-measured Internet topology. Our results show that, compared to the current practice, GIRO can reduce the geographic distance for 70% of the existing BGP paths, and the reduction is more than 40% for about 20% of the paths. Furthermore, encoding geographic information into IP addresses also enables GIRO to apply geographical route aggregation, and a combination of geographic and topological aggregation can lead to 75% reduction of the current BGP routing table size.

Today's Internet provides a global data delivery service to millions of end users and routing protocols play a critical role in this service. It is important to be able to identify and diagnose any problems occurring in Internet routing. However, the Internet's sheer size makes this task difficult. One cannot easily extract out the most important or relevant routing information from the large amounts of data collected from multiple routers. To tackle this problem, we have developed Link-Rank, a tool to visualize Internet routing changes at the global scale. Link-Rank weighs links in a topological graph by the number of routes carried over each link and visually captures changes in link weights in the form of a topological graph with adjustable size. Using Link-Rank, network operators can easily observe important routing changes from massive amounts of routing data, discover otherwise unnoticed routing problems, understand the impact of topological events, and infer root causes of observed routing changes.

The number of multi-homed user sites has been rapidly increasing in recent years, where a campus or company network is connected to multiple Internet service providers' networks to improve Internet service reliability. In this paper, we examine the impact of multi-homing via BGP on routing stability and network reliability. More specifically, we compare single-homed prefixes with multi-homed prefixes in terms of the number of routing update messages and the duration of unreachability. Our results show that, on average, single-homed prefixes both generates fewer routing updates than multi-homed prefixes, and provide higher reliability than 97% of multi-homed prefixes (which have a low degree of multi-homing). These results suggest the need to further improve BGP's stability to enable Internet users to gain the expected reliability benefit from multi-homing.

Failures at the BGP level can have significant impact on the overall Internet. Understanding the behavior of BGP is thus both an important practical challenge and an interesting research problem. To understand the true dynamics, and help interpret the multiple gigabytes of BGP log data, we have developed the "Link-Rank" graphical toolset. Link-Rank weighs the links between autonomous systems by the number of routing prefixes going through each link. Tracing these graphs over time results in a directed graph that shows the weight changes of the logical inter-AS links. From this graph one can easily visualise the complex BGP path changes and also combine views from multiple vantage points, to get a better picture of global routing dynamics. We illustrate the usefulness of Link-Rank by using it to examine BGP routing dynamics in three example cases. These examples show Link-Rank is able to help BGP analysts estimate the scope of routing changes and to reveal important routing dynamics in the presence of superfluous BGP update messages.

Due to the Internet's sheer size, complexity, and various routing policies, it is difficult if not impossible to locate the causes of large volumes of BGP update messages that occur from time to time. To provide dependable global data delivery we need diagnostic tools that can pinpoint the exact connectivity changes. We describe an algorithm, called MVSChange that can pin down the origin of routing changes due to any single link failure or link restoration. Using a simplified model of BGP, called simple path vector protocol (SPVP), and a graph model of the Internet, MVSChange takes as input the SPVP update messages collected from multiple vantage points and accurately locates the link that initiated the routing changes. We provide theoretical proof for the correctness of the design.