Hyunseok Chang

Nokia Bell Labs

The rapid growth of satellite network operators (SNOs) has revolutionized broadband communications, enabling global connectivity and bridging the digital divide. As these networks expand, it is important to evaluate their performance and efficiency. This paper presents the first comprehensive study of SNOs. We take an opportunistic approach and dev...

It is commonly assumed that the end-to-end networking performance of edge offloading is purely dictated by that of the network connectivity between end devices and edge computing facilities, where ongoing innovation in 5G/6G networking can help. However, with the growing complexity of edge-offloaded computation and dynamic load balancing requiremen...

Since the outbreak of the COVID-19 pandemic, videoconferencing has become the default mode of communication in our daily lives at homes, workplaces and schools, and it is likely to remain an important part of our lives in the post-pandemic world. Despite its significance, there has not been any systematic study characterizing the user-perceived per...

Since the outbreak of the COVID-19 pandemic, videoconferencing has become the default mode of communication in our daily lives at homes, workplaces and schools, and it is likely to remain an important part of our lives in the post-pandemic world. Despite its significance, there has not been any systematic study characterizing the user-perceived per...

Modern data centers are witnessing fast-growing east-west traffic on their network infrastructure due to the highly distributed data center applications. Motivated by the heterogeneity of such application workloads, we propose in this article an extensible network management architecture called MAGNet which enables application-aware intra-data ce...

Emerging microservices-based workloads introduce new security risks in today's data centers as attacks can propagate laterally within the data center relatively easily by exploiting cross-service dependencies. As countermeasures for such attacks, traditional perimeterization approaches, such as network-endpoint-based access control, do not fare wel...

This paper proposes Muppet, an edge-based multiprotocol architecture for large scale IoT deployment and service automation. The crux of Muppet is a P4-based switch that inserts itself in between communicating IoT devices that can use different protocols. The switches are networked over IP to support wide area deployment, and managed using centraliz...

Stream processing pipelines operated by current big data streaming frameworks present two problems. First, the pipelines are not flexible, controllable, and programmable enough to accommodate dynamic streaming application needs. Second, the application-level data routing over the pipelines do not exhibit optimal performance for increasingly common...

Increasingly, smart Network Interface Cards (sNICs) are being used in data centers to offload networking functions (NFs) from host processors thereby making these processors available for tenant applications. Modern sNICs have fully programmable, energy-efficient multi-core processors on which many packet processing functions, including a full-blow...

In a vision-based 3D indoor localization system, conducting localization of user's device at a high frame rate is important to support real-time augment reality applications. However, vision-based 3D localization typically involves 2D keypoint detection and 2D-3D matching processes, which are in general too computationally intensive to be carried o...

Edge services become increasingly important as the Internet transforms into an Internet of Things (IoT). Edge services require bounded latency, bandwidth reduction between the edge and the core, service resiliency with graceful degradation, and access to resources visible only inside the NATed and secured edge networks. While the data center based...

Live broadcast over a peer-to-peer (P2P) network imposes a unique set of challenges to a digital rights management (DRM) system. Highly correlated service request arrivals at the start of a live event require peak-load provisioning if clients acquire licenses at playback time. Distributing the license management load across a P2P network requires t...

An enterprise uses VPNs, leased from a service provider, to interconnect multiple sites that are geographically apart. The service providers, as they start providing cloud-based services, are finding themselves well-positioned to providing storage services in the cloud for an enterprise, and make the service accessible through the existing VPN conn...

Television transmitted over IP (IPTV) presents numerous opportunities for users as well as service providers, and has attracted significant interest from industry as well as research communities in recent years. Among the emerging IPTV delivery architectures, the peer-to-peer based delivery mechanism is considered attractive due to the relative eas...

Live broadcast over a P2P (peer-to-peer) network imposes a unique set of challenges to a digital rights management system. Highly correlated service request arrivals at the start of a live event require peak-load provisioning if clients acquire licenses at playback time. Distributing the license management load across a P2P network requires the dig...

Large-scale data processing needs of enterprises to- day are primarily met with distributed and parallel computing in data centers. MapReduce has emerged as an important program- ming model for these environments. Since today's data centers run many MapReduce jobs in parallel, it is important to find a good scheduling algorithm that can optimize th...

A number of commercial peer-to-peer (P2P) systems for live streaming have been introduced in recent years. The behavior of these popular systems has been extensively studied in several measurement papers. Due to the proprietary nature of these commercial systems, however, these studies have to rely on a "black-box" approach, where packet traces are...

Television transmitted over IP (IPTV) presents numerous opportunities for users as well as service providers, and has attracted significant interest from business and research communities in recent years. Among the emerging IPTV delivery architectures, the peer-to-peer based delivery mechanism is considered attractive due to the relative ease of se...

La télévision transmise par le protocole Internet (IPTV) présente de nombreuses possibilités tant pour les utilisateurs que pour les fournisseurs de services. Elle a attiré de manière significative les entreprises et depuis quelques années, la communauté de la recherche. Parmi les architectures de diffusion de l'IPTV, le mécanisme de diffusion TV p...

A number of commercial peer-to-peer systems for live streaming, such as PPLive, Joost, LiveStation, SOPCast, TVants, etc. have been introduced in recent years. The behavior of these popular systems has been extensively studied in several measurement papers. Due to the proprietary nature of these commercial systems, however, these studies have to re...

A P2PTV system allows users to watch live video streams redistributed by other users via a peer-to-peer (P2P) network. In an ideal world, each peer in a P2P network would be able to redistribute more bytes than it receives. A P2PTV system built from such peers can support a virtually unlimited number of peers; with only a single copy of content str...

The Internet's layered architecture and organizational structure give rise to a number of different topologies, with the lower layers defining more physical and the higher layers more virtual/logical types of connectivity structures. These structures are very dif-ferent, and successful Internet topology modeling requires annotating the nodes and ed...

Compared to other large-scale, complex systems, one of the most appealing features of the Internet is that a thorough understanding of its component technologies combined with a unique ability to measure the network means that most of the models and theories proposed for explaining the Internet's observed structure and behavior can be in general un...

Internet connectivity at the AS level, defined in terms of pairwise logical peering relationships, is constantly evolving. This evolution is largely a response to economic, political, and technological changes that impact the way ASs conduct their business. We present a new framework for modeling this evolutionary process by identifying a set of cr...

Internet connectivity at the Autonomous System (AS)-level, defined in terms of pairwise business peering relationships, is constantly evolving. This evolution is largely a response to economic, political, and technological changes that impact the way ASs conduct their business. Existing research activities focusing on modeling AS-level Internet con...

Recently developed techniques have been very success- ful in accurately estimating intra-Autonomous System (AS) traffic matrices. These techniques rely on link measure- ments, flow measurements, or routing-related data to infer traffic demand between every pair of ingress-egress points of an AS. They also illustrate an inherent mismatch be- tween d...

We call end-hosts behind network address translator (NAT) gateways or firewalls guarded hosts, and otherwise open hosts. In this paper, we empirically measure the prevalence of guarded hosts in two popular peer-to-peer file sharing systems, eDonkey and Gnutella, and study the characteristics of their shared files. By performing passive and active p...

Two ASs are connected in the Internet AS graph only if they have a business "peering relationship." By focusing on the AS subgraph ASPC whose links represent provider-customer relationships, we develop a new optimization-driven model for Internet growth at the ASPC level. The model's defining feature is an explicit construction of a novel class of...

Two ASs are connected in the Internet AS graph only if they have a business "peering relationship." By focusing on the AS subgraph ASPC whose links represent provider-customer relationships, we present an empirical study that identifies three crucial causal forces at work in the design of AS connectivity: (i) AS-geography, i.e., locality and number...

Two ASs are connected in the Internet AS graph only if they have a business "peering relationship." By focusing on the AS subgraph ASPC whose links represent provider-customer relationships, we develop a new optimization-driven model for Internet growth at the ASPC level. The model's defining feature is an explicit construction of a novel class of...

Recent studies on AS-level Internet connectivity have attracted considerable attention. These studies have exclusively relied on BGP data from the Oregon route-views [University of Oregon Route Views Project, http://www.routeviews.org] to derive some unexpected and intriguing results. The Oregon route-views data sets reflect AS peering relationship...

In a recent paper, Faloutsos et al. [1] found that the inter Autonomous System (AS) topology exhibits a power-law vertex degree distribution. This result was quite unexpected in the networking community and stirred significant interest in exploring the possible causes of this phenomenon. The work of Barabasi and Albert [2] and its application to ne...

Recent studies concerning the Internet connectivity at the AS level have attracted considerable attention. These studies have exclusively relied on BGP measurements collected by the National Laboratory for Applied Network Research (NLANR) in deriving some of the unexpected and intriguing results. The NLANR data sets reflect AS peering relationships...

A number of recent studies characterize AS-level topology of the Internet by exploiting connectivity information contained in BGP routing tables. In this paper, we present an alternative method for discovering AS connectivity by inferring individual AS connections from the Internet's router-level topology. This methodology has several advantages ov...

In Comfortably seated at a workstation equipped with a direct, high-speed network connection, it is easy to think of available Internet connectivity as an inalienable right. While new technologies such as cable modems and digital subscriber lines promise to bring similar capabilities to every home, however, the mobile computing landscape looming ov...

This paper presents a method of incorporating physical layout aspects into high-level synthesis (HLS) process for performance optimization. First we extract accurate interconnection delay from a layout design obtained after placement and routing and back-annotate the extracted delay to the control/data flow graph (CDFG). Then we run HLS again on th...