7730327
Guest Editors' Introduction: Securing the Domain Name System
Virtually every Internet application relies on the Domain Name System, but security wasn't a major goal of its original design. The result is several critical vulnerabilities, reviewed in this introduction to a special issue on DNS security. To address the security challenges, the community developed the DNS Security Extensions (DNSSEC), which are undergoing deployment. The articles in this special issue summarize key aspects of how to deploy DNSSEC at authoritative servers, resolvers, and public key learning.
8791084
Collecting the internet AS-level topology
At the inter-domain level, the Internet topology can be represented by a graph with Autonomous Systems (ASes) as nodes and AS peerings as links. This AS-level topology graph has been widely used in a variety of research efforts. Conventionally this topology graph is derived from routing tables collected by Route Views or RIPE RIS. In this work, we assemble the most complete AS-level topology by extending the conventional method along two dimensions. First, in addition to using data from RouteViews and RIPE RIS, we also collect data from many other sources, including route servers, looking glasses, and routing registries. Second, in addition to using routing tables, we also accumulate topological information from routing updates over time. The resulting topology graph on a recent day contains 44% more links and 3% more nodes than that from using RouteViews routing tables alone. Our data collection and topology generation process have been automated, and we publish the latest topology on the web on a daily basis.
5219400
Timer Interaction in Route Flap Damping
Route Flap Damping is a mechanism generally used in network routing protocols. Its goal is to limit the global impact of unstable routes by temporarily suppressing routes with rapid changes over short time periods. Although route damping is a clearly defined and simple procedure at each router, its effect in a large network setting is not well understood. We show that the current damping design leads to the intended behavior only under persistent route flapping. When the number of flaps is small, the global routing dynamics deviates significantly from the expected behavior with a longer convergence delay. Previous work observed that a single route flap can falsely trigger route suppression due to path exploration. However our simulations show that this false suppression only accounts for 30% of the convergence delay after a single route flap. Our study reveals previously unknown interactions between reuse timers at different routers. Route suppression and reuse at different routers are triggered at different times and thus affect the number of updates received by other routers. In turn, this impacts other routers' damping behavior. We propose to use Root Cause Notification to eliminate both false suppression and undesirable timer interaction
314559
Improving BGP convergence through consistency assertions
This paper presents a new mechanism for improving the convergence properties of path vector routing algorithms, such as BGP. Using a route's path information, we develop two consistency assertions for path vector routing algorithms that are used to compare similar routes and identify infeasible routes. To apply these assertions in BGP, mechanisms to signal failure/policy withdrawal, and traffic engineering are provided. Our approach was implemented and deployed in a BGP testbed and evaluated using simulation. By identifying and ignoring the infeasible routes, we achieved substantial reduction in both BGP convergence time and the total number of intermediate route changes.
1040083
Understanding BGP behavior through a study of DoD prefixes
BGP is the de-facto inter-domain routing protocol and it is essential to understand how well BGP performs in the Internet. As a step toward this understanding, this paper studies the routing performance of a sample set of prefixes owned by the USA Department of Defense (DoD). We examine how reliably the sample set is connected to the Internet and how it affects the rest of the Internet. We show that our sample set receives reliable connectivity, with the exception of a few prefixes. We also show that, on average, the sample set has minimal impact on global routing, but certain BGP features used by DoD routers result in periods of excessive routing overhead. During some stressful periods, our sample set, only 0.2% of all prefixes, contributed over 80% of a particular BGP update class. We explain how the BGP design allows certain local changes to propagate globally and amplifies the impact of our sample prefixes.
17767601
FRTR: a scalable mechanism for global routing table consistency
This paper presents a scalable mechanism, fast routing table recovery (FRTR), for detecting and correcting route inconsistencies between neighboring BGP routers. The large size of today's global routing table makes the conventional periodic update approach, used by most routing protocols, infeasible. FRTR lets neighboring routers periodically exchange Bloom filter digests of their routing state. The digest exchanges not only enable the detection of potential inconsistencies during normal operations, but also speed up recovery after a BGP session reset. FRTR achieves low bandwidth overhead by using small digests, and it achieves strong consistency by "salting" the digests with random seeds to remove false-positives. Our analysis and simulation results show that, with one round of message exchanges, FRTR can detect and recover over 91% of random errors that the current BGP would have missed with an overhead as low as 1.3% of a full routing table exchange. With salted digests FRTR can detect and recover all the errors with a probability close to 100% after a few rounds of message exchanges.
34947514
A coherent moral relativism
Moral relativism is an attractive position, but also one that it is difficult to formulate. In this paper, we propose an alternative way of formulating moral relativism that locates the relativity of morality in the property that makes moral claims true. Such an approach, we believe, has significant advantages over other possible ways of formulating moral relativism. We conclude by considering a few problems such a position might face.