Georgios Smaragdakis

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We study the impact of heterogeneity of nodes, in terms of their energy, in wireless sensor networks that are hierarchically clustered. In these networks some of the nodes become cluster heads, aggregate the data of their cluster members and transmit it to the sink. We assume that a percentage of the population of sensor nodes is equipped with additional(More)
Many emerging scientific and industrial applications require transferring multiple Tbytes of data on a daily basis. Examples include pushing scientific data from particle accelerators/colliders to laboratories around the world, synchronizing data-centers across continents, and replicating collections of high definition videos from events taking place at(More)
The Domain Name System (DNS) is a fundamental building block of the Internet. Today, the performance of more and more applications depend not only on the responsiveness of DNS, but also the exact answer returned by the queried DNS resolver, e.g., for Content Distribution Networks (CDN). In this paper, we compare local DNS resolvers against GoogleDNS and(More)
Content delivery systems constitute a major portion of today's Internet traffic. While they are a good source of revenue for Internet Service Providers (ISPs), the huge volume of content delivery traffic also poses a significant burden and traffic engineering challenge for the ISP. The difficulty is due to the immense volume of transfers, while the traffic(More)
Today a spectrum of solutions are available for istributing content over the Internet, ranging from commercial CDNs to ISP-operated CDNs to content-provider-operated CDNs to peer-to-peer CDNs. Some deploy servers in just a few large data centers while others deploy in thousands of locations or even on millions of desktops. Recently, major CDNs have formed(More)
Internet eXchange Points (IXPs) are generally considered to be the successors of the four Network Access Points (NAPs) that were mandated as part of the decommissioning of the National Science Foundation Network (NSFNET) in 1994/95 to facilitate the transition from the NSFNET to the "public Internet" as we know it today. While this popular view does not(More)
Today, a large fraction of Internet traffic is originated by Content Delivery Networks (CDNs). To cope with increasing demand for content, CDNs have deployed massively distributed infrastructures. These deployments pose challenges for CDNs as they have to dynamically map end-users to appropriate servers without being full+y aware of the network conditions(More)
The recently proposed DNS extension, EDNS-Client-Subnet (ECS), has been quickly adopted by major Internet companies such as Google to better assign user requests to their servers and improve end-user experience. In this paper, we show that the adoption of ECS also offers unique, but likely unintended, opportunities to uncover details about these companies'(More)
Annotating Internet interconnections with robust physical coordinates at the level of a building facilitates network management including interdomain troubleshooting, but also has practical value for helping to locate points of attacks, congestion, or instability on the Internet. But, like most other aspects of Internet interconnection, its geophysical(More)
The effectiveness of service provisioning in large-scale networks is highly dependent on the number and location of service facilities deployed at various hosts. The classical, centralized approach to determining the latter would amount to formulating and solving the <i>uncapacitated k-median</i> (UKM) problem (if the requested number of facilities is(More)