Robert Kisteleki’s scientific contributions

RIPE Atlas consists of ∼9.1K probes (as of Jan 2017) connected in core, access and home networks. RIPE Atlas has recently (Jul 2014) introduced a tagging mechanism for fine-grained vantage point selection of probes. These tags are subdivided into user and system tags. User tags are based on a manual process which is largely dependent on proactive participation of probe hosts. We show that only ∼2.8% of probe hosts ever update their user tags which may lead to user tags that tend to become stale over time. System tags on the other hand being automatically assigned and frequently updated (every 4 hours) are stable and accurate. We show an application of system tags by performing a vantage point selection of dual-stacked probes. This exploration reveals that with ∼2.3K (∼26%) connected dual-stacked probes, RIPE Atlas provides the richest source of vantage points for IPv6 measurement studies. These dual-stacked probes span 88 countries and cover 822 ASNs. ∼83% of these dual-stacked probes are connected within access networks with 782 probes deployed at homes with native IPv6 connectivity. These home dual-stacked probes are evenly split across DSL, cable and fibre deployments. We show that IPv6 latencies from these probes to RIPE Atlas anchors appear comparable to IPv4, although IPv4 performs marginally better. By applying a correlation against APNIC IPv6 user population estimate, we further reveal underrepresented countries (such as BE and JP) which would benefit from deployment of more probes for IPv6 measurement studies.

The user experience of an Internet service depends partly on the availability and speed of the Domain Name System (DNS). DNS operators continually need to identify and solve problems that can be located at the end user, a name server, or somewhere in between. In this paper, we show how DNSMON, a production service for measuring and comparing the availability and responsiveness of key name servers, correlates and visualizes different types of measurements collected by RIPE Atlas vantage points worldwide. DNSMON offers an interactive view, both historic and near real-time, at different levels of detail. It has successfully revealed and allowed analysis of many operational issues, including less obvious ones.

Multi-paradigm design is one of the emerging paradigm in software technology. Multi-paradigm helps the designer to choose the right paradigm for each problem domain. In one specific case of variable problem scenarious where the objects we use has little or no common structure but there is similar behaviour. In this cases we successfully use the paradigm of generic programming. The goal of this style is to reveal the foundations and programming methods of generic and therefore reusable components and libraries. Until quite recently generic programming has only one well-known existing implementation: the C++ Standard Template Library (STL). STL has a certain goal: there are data structures and specific algorithms working on them. This is a very specific problem-domain which call affect the implementation. We think this one implementation of the generic programming is not enough to examine this new paradigm. Therefore we try to define a set of demonstrative generic libraries, implement them as working software, and making comparison on the internal structure: select common patterns and leave problem or implementation-specific parts. We present in this article the Graphical Template Library (GTL). GTL works on graphical shapes like circle or polygon, implementing common functions like move, rotate, etc. The idea of GTL comes from real-world applications. Graphical drawing programs can benefit from this kind of design. One of the main advantages of the use of generic programming is the significant, reduce of code complexity. The average library has n objects on k basic types with m algorithms, has O(n * k * m) methods developed by object-oriented way, but this can be reduced to O(n * m) with generic paradigm. Iterators are in central role of generic programming. Iterators are the fundamental program elements connecting data structures and algorithms. STL has a certain hierarchy of iterators. In GTL we extend the set of iterators, but we insert them into STL’s hierarchy. The new iterators have practical usage in generic libraries and parallel environments. These iterators need further researches.