Vasileios Pappas

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The scalability of modern data centers has become a practical concern and has attracted significant attention in recent years. In contrast to existing solutions that require changes in the network architecture and the routing protocols, this paper proposes using traffic-aware virtual machine (VM) placement to improve the network scalability. By optimizing(More)
During the past twenty years the Domain Name System (DNS) has sustained phenomenal growth while maintaining satisfactory performance. However, the original design focused mainly on system robustness against physical failures, and neglected the impact of operational errors such as misconfigurations. Our recent measurement effort revealed three specific types(More)
The natural world is enormous, dynamic, incredibly diverse, and highly complex. Despite the inherent challenges of surviving in such a world, biological organisms evolve, self-organize, self-repair, navigate, and flourish. Generally, they do so with only local knowledge and without any centralized control. Our computer networks are increasingly facing(More)
We present the initial results from our evaluation study on the performance implications of anycast in DNS, using four anycast servers deployed at top-level DNS zones. Our results show that 15% to 55% of the queries sent to an anycast group, are answered by the topologically closest server and at least 10% of the queries experience an additional delay in(More)
The current Domain Name System (DNS) follows a hierarchical tree structure. Several recent efforts proposed to re-implement DNS as a peer-to-peer network with a flat structure that uses Distributed Hash Tables (DHT) to improve the system availability. In this paper we compare the performance and availability of these two designs, enabled by caching and(More)
In this paper, we return to the drawing board to rethink the basic approach to multi-hop forwarding for highly dynamic wireless networks. The result is Listen First, Broadcast Later (LFBL), a surprisingly minimalist forwarding protocol. LFBL is topology-agnostic, that is, it has no knowledge of neighbors, routes, or next hops. LFBL receivers, not senders,(More)
We propose a new Data Center Network (DCN) architecture, based on the principles of Information-Centric Networking (ICN). Our Info-Centric Data Center Network (IC-DCN) addresses many of the pain-points in current DCNs, such as network scalability, host mobility, etc. At the same time, IC-DCN introduces a number of new features to the current(More)
The Dynamic Host Configuration Protocol (DHCP) was introduced nearly 20 years ago as a mechanism for hosts to automatically acquire IP addresses. While the protocol remains the same, its usage has evolved, especially in the last decade with the introduction of mobile devices and wireless local area networks. In this paper we investigate the impact that new(More)
In this paper we present a troubleshooting tool designed to identify a number of DNS configuration errors. These errors range from commonly seen misconfigurations that are well known among DNS operators, such as lame delegations, to less known ones, such as cyclic zone dependencies. Left unnoticed, these misconfigurations can seriously affect the(More)