The simple act of slowly varying the parameters of a quantum system so that it remains always in its ground state is extremely rich from an information processing point of view. For an ideal, closed system, this adiabatic evolution is equivalent to full quantum computation, and it is convenient for establishing quantum algorithms for optimization. This review presents adiabatic quantum algorithms, proves the closed-system equivalence of the adiabatic and circuit models of quantum computation, reviews the placement of adiabatic quantum computation in the more general classification of computational complexity theory, and discusses the case of ``stoquastic'' quantum evolutions.

Adiabatic quantum computation

The largest IXPs carry on a daily basis traffic volumes in the petabyte range, similar to what some of the largest global ISPs reportedly handle. This little-known fact is due to a few hundreds of member ASes exchanging traffic with one another over the IXP's infrastructure. This paper reports on a first-of-its-kind and in-depth analysis of one of the largest IXPs worldwide based on nine months' worth of sFlow records collected at that IXP in 2011.A main finding of our study is that the number of actual peering links at this single IXP exceeds the number of total AS links of the peer-peer type in the entire Internet known as of 2010! To explain such a surprisingly rich peering fabric, we examine in detail this IXP's ecosystem and highlight the diversity of networks that are members at this IXP and connect there with other member ASes for reasons that are similarly diverse, but can be partially inferred from their business types and observed traffic patterns. In the process, we investigate this IXP's traffic matrix and illustrate what its temporal and structural properties can tell us about the member ASes that generated the traffic in the first place. While our results suggest that these large IXPs can be viewed as a microcosm of the Internet ecosystem itself, they also argue for a re-assessment of the mental picture that our community has about this ecosystem.

http://conferences.sigcomm.org/sigcomm/2012/paper/sigcomm/p163.pdf

Anatomy of a large european IXP

Business relationships between ASes in the Internet are typically confidential, yet knowledge of them is essential to understand many aspects of Internet structure, performance, dynamics, and evolution. We present a new algorithm to infer these relationships using BGP paths. Unlike previous approaches, our algorithm does not assume the presence (or seek to maximize the number) of valley-free paths, instead relying on three assumptions about the Internet's inter-domain structure: (1) an AS enters into a provider relationship to become globally reachable; and (2) there exists a peering clique of ASes at the top of the hierarchy, and (3) there is no cycle of p2c links. We assemble the largest source of validation data for AS-relationship inferences to date, validating 34.6% of our 126,082 c2p and p2p inferences to be 99.6% and 98.7% accurate, respectively. Using these inferred relationships, we evaluate three algorithms for inferring each AS's customer cone, defined as the set of ASes an AS can reach using customer links. We demonstrate the utility of our algorithms for studying the rise and fall of large transit providers over the last fifteen years, including recent claims about the flattening of the AS-level topology and the decreasing influence of tier-1 ASes on the global Internet.

/pdf/as-relationships-customer-cones-and-validation-3hatwfq0l5.pdf

AS relationships, customer cones, and validation

We consider the point-to-point (approximate) shortest-path query problem, which is the following generalization of the classical single-source (SSSP) and all-pairs shortest-path (APSP) problems: we are first presented with a network (graph). A so-called preprocessing algorithm may compute certain information (a data structure or index) to prepare for the next phase. After this preprocessing step, applications may ask shortest-path or distance queries, which should be answered as fast as possible.Due to its many applications in areas such as transportation, networking, and social science, this problem has been considered by researchers from various communities (sometimes under different names): algorithm engineers construct fast route planning methods; database and information systems researchers investigate materialization tradeoffs, query processing on spatial networks, and reachability queries; and theoretical computer scientists analyze distance oracles and sparse spanners. Related problems are considered for compact routing and distance labeling schemes in networking and distributed computing and for metric embeddings in geometry as well.In this survey, we review selected approaches, algorithms, and results on shortest-path queries from these fields, with the main focus lying on the tradeoff between the index size and the query time. We survey methods for general graphs as well as specialized methods for restricted graph classes, in particular for those classes with arguable practical significance such as planar graphs and complex networks.

/pdf/shortest-path-queries-in-static-networks-t3dlcej7at.pdf

Shortest-path queries in static networks

is a network or group of networks under a common administration and with common routing policies. BGP is used to exchange routing information for the Internet and is the protocol used between Internet service providers (ISP). Customer networks, such as universities and corporations, usually employ an Interior Gateway Protocol (IGP) such as RIP or OSPF for the exchange of routing information within their networks. Customers connect to ISPs, and ISPs use BGP to exchange customer and ISP routes. When BGP is used between autonomous systems (AS), the protocol is referred to as External BGP (EBGP). If a service provider is using BGP to exchange routes within an AS, then the protocol is referred to as Interior BGP (IBGP).

Border Gateway Protocol

Formally, the Internet inter-domain routing system is a collection of networks, their policies, peering relationships and organizational affiliations, and the addresses they advertize. It also includes components like Internet exchange points. By its very definition, each and every aspect of this system is impacted by BGP, the de-facto standard inter-domain routing protocol. The element of this inter-domain routing system that has attracted the single-most attention within the research community has been the "inter-domain topology". Unfortunately, almost from the get go, the vast majority of studies of this topology, from definition, to measurement, to modeling and analysis, have ignored the central role of BGP in this problem. The legacy is a set of specious findings, unsubstantiated claims, and ill-conceived ideas about the Internet as a whole. By presenting a BGP-focused state-of-the-art treatment of the aspects that are critical for a rigorous study of this inter-domain topology, we demystify in this paper many "controversial" observations reported in the existing literature. At the same time, we illustrate the benefits and richness of new scientific approaches to measuring, modeling, and analyzing the inter-domain topology that are faithful to the BGP-specific nature of this problem domain.

/pdf/10-lessons-from-10-years-of-measuring-and-modeling-the-1h32am5kzw.pdf

10 Lessons from 10 Years of Measuring and Modeling the Internet's Autonomous Systems

Here we consider using quantum annealing to solve Set Cover with Pairs (SCP), an NP-hard combinatorial optimization problem that plays an important role in networking, computational biology, and biochemistry. We show an explicit construction of Ising Hamiltonians whose ground states encode the solution of SCP instances. We numerically simulate the time-dependent Schrodinger equation in order to test the performance of quantum annealing for random instances and compare with that of simulated annealing. We also discuss explicit embedding strategies for realizing our Hamiltonian construction on the D-wave type restricted Ising Hamiltonian based on Chimera graphs. Our embedding on the Chimera graph preserves the structure of the original SCP instance and in particular, the embedding for general complete bipartite graphs and logical disjunctions may be of broader use than that the specific problem we deal with.

/pdf/solving-set-cover-with-pairs-problem-using-quantum-annealing-2f0bm4lo7y.pdf

Solving Set Cover with Pairs Problem using Quantum Annealing.

Here we consider using quantum annealing to solve Set Cover with Pairs (SCP), an NP-hard combinatorial optimization problem that play an important role in networking, computational biology, and biochemistry. We show an explicit construction of Ising Hamiltonians whose ground states encode the solution of SCP instances. We numerically simulate the time-dependent Schrodinger equation in order to test the performance of quantum annealing for random instances and compare with that of simulated annealing. We also discuss explicit embedding strategies for realizing our Hamiltonian construction on the D-wave type restricted Ising Hamiltonian based on Chimera graphs. Our embedding on the Chimera graph preserves the structure of the original SCP instance and in particular, the embedding for general complete bipartite graphs and logical disjunctions may be of broader use than that the specific problem we deal with.

Solving Set Cover with Pairs Problem Using Quantum Annealing

During the last few years, we have observed a rapid increase in the number of robots that are manufactured and marketed for our homes. These social robots promise to become not just a personal assistant, but a companion that knows its owner»s tastes and habits. As the advances in artificial intelligence move the dream of home robots closer, exploitation techniques that could specifically target these robots need to be thoroughly examined. In this paper, we present our observations from performing an initial vulnerability analysis to a commercial social robot. Our results indicate that both manufacturers and application developers need to take cybersecurity into account when considering the use of their robots.

A Case Study on the Cybersecurity of Social Robots

Internet Service Providers (ISPs) need to balance multiple opposing objectives. On one hand, they strive to offer innovative services to obtain competitive advantages; on the other, they have to interconnect with potentially competing ISPs to achieve reachability, and coordinate with them for certain services. The complexity of balancing these objectives is reflected in the diversity of policies of the Border Gateway Protocol (BGP), the standard inter-domain routing protocol. Unforeseen interactions among the BGP policies of different ISPs can cause routing anomalies. In this work, we propose a methodology to allow ISPs to check their BGP policy configurations for guaranteed convergence to a single stable state. This requires that a set of ISPs share their configurations with each other, or with a trusted third party. Compared to previous approaches to BGP safety, we (1) allow ISPs to use a richer set of policies, (2) do not modify the BGP protocol itself, and (3) detect not only instability, but also multiple stable states. Our methodology is based on the extension of current theoretical frameworks to relax their constraints and use incomplete data. We believe that this provides a rigorous foundation for the design and implementation of safety checking tools.

/pdf/detecting-unsafe-bgp-policies-in-a-flexible-world-26d7qlkr2z.pdf

Debbie Perouli

Papers

10 Lessons from 10 Years of Measuring and Modeling the Internet's Autonomous Systems

Solving Set Cover with Pairs Problem using Quantum Annealing.

Solving Set Cover with Pairs Problem Using Quantum Annealing

A Case Study on the Cybersecurity of Social Robots

Detecting unsafe BGP policies in a flexible world