Munyoung Lee

WAVE: Popularity-based and collaborative in-network caching for content-oriented networks

In content-oriented networking, content files are typically cached in network nodes, and hence how to cache content files is crucial for the efficient content delivery and cache storage utilization. In this paper, we propose a content caching scheme, WAVE, in which the number of chunks to be cached is adjusted based on the popularity of the content. In WAVE, an upstream node recommends the number of chunks to be cached at its downstream node, which is exponentially increased as the request count increases. Simulation results reveal that the average hop count of content delivery of WAVE is lower than other schemes, and the inter-ISP traffic volume of WAVE is the second lowest (CDN is the lowest). Also, WAVE achieves higher cache hit ratio and fewer frequent cache replacements than other on-demand caching strategies.

SCAN: Scalable Content Routing for Content-Aware Networking

Since Internet routers are not aware of the contents being forwarded, the same content file is often delivered multiple times inefficiently. Similarly, users cannot exploit a nearby copy of the content of interest unless the content file is serviced by costly content delivery networks. Prior studies on the content-aware routing for efficient content delivery suffer from the scalability problem due to a large number of contents. We propose a scalable content routing, dubbed SCAN, which can exploit nearby and multiple content copies for the efficient delivery. SCAN exchanges the information of the cached contents using Bloom filter. Compared with IP routing, SCAN can offer reduced delivery latency, reduced traffic volume, and load balancing among links.

How can an ISP merge with a CDN

As delivering contents has become the dominant usage of the Internet, efficient content distribution is one of the hottest research areas in the network community. In future networks, it is anticipated that network entities such as routers will be equipped with in-network storage due to the trend of ever decreasing storage cost. In this article, we propose a novel content delivery architecture called ISP-centric content delivery (iCODE) by which an ISP can provide content delivery services as well. iCODE can provide efficient content delivery services since an ISP can cache contents in routers with storage modules considering traffic engineering and the locality of the content requests. Compared to CDN and P2P systems, iCODE can offer reduced delivery latency by placing the contents closer to end hosts, and incentives to ISPs by reducing inter- ISP traffic and allowing traffic engineering. We also discuss the technical and business issues to realize the iCODE architecture.

Publisher mobility support in content centric networks

As the high speed Internet and the smart devices become prevalent, it is expected that the traffic volume of the video conferencing/broadcasting on the mobile devices is increasing explosively. One of the promising solutions for the traffic explosion problem is the content centric networking (CCN), which solves the problem by focusing on the content instead of the location. Even though CCN can provide better delivery efficiency, robustness, security, and native subscriber mobility, little attention is paid to the publisher mobility problem, where the mobile devices produce the real-time traffic. In this paper, we propose PMC, a publisher mobility support protocol in CCN. By introducing two names and corresponding operations at the routers, PMC supports publisher mobility for the mobile video conferencing and broadcasting without violating the original CCN architecture. We believe that PMC is a validated and secured scheme following the philosophy of the CCN architecture to support mobile publisher.

Content discovery for information-centric networking

The information-centric networking (ICN) adopts a content name as a network identifier and utilizes in-network storages to cache the contents. With the name-based routing and content caching, ICN can provide substantial benefits such as faster content retrieval and network traffic reduction by exploiting a nearby (cached) copy of content and reducing duplicated transmissions for the same content request. Prior researches on ICN usually rely on an opportunistic cache-hit (happen-to-meet) to utilize the in-network storages. In the happen-to-meet fashion, only the content cached on the path towards the content source can be utilized, which limits the network-wide usage of the in-network storages. To exploit cached contents better, we propose a content discovery scheme, dubbed SCAN, which can exploit nearby content copies for the efficient delivery. SCAN exchanges the cached content information among the neighbor routers using Bloom filters for the content discovery. With extensive simulations, SCAN shows better performance than a happen-to-meet cache-hit scheme in terms of average hop counts, traffic volume, and load balancing among links.

DOVE: Data Offloading through Spatio-Temporal Rendezvous in Vehicular Networks

The increasing mobile traffic is becoming a serious concern for mobile network providers. To address the traffic explosion problem, there have been a lot of efforts to offload the traffic from cellular networks to other networks, such as WiFi hotspots and femtocells. In this paper, we explore the potential benefits of vehicular networks for data offloading and propose a Data Offloading framework through Vehicular nEtworks (DOVE), which reduces the cellular traffic for in-vehicle data services in a cost effective way. DOVE exploits vehicle trajectories for offloading purposes so that content files requested by vehicles can be delivered via vehicular networks rather than via cellular networks for economical purposes. We formulate the problem of selecting offloading positions as a spatio-temporal set-covering problem, and propose a time-prediction based set-covering algorithm using vehicle trajectories. Simulation results show that our DOVE framework can significantly reduce 57% of cellular link usage by performing data offloading through vehicular networks.

Decentralized and autonomous content overlay networking (DACON) with WiFi access points

Accessing contents from mobile devices becomes more and more proliferated and hence the need for the content distribution in the pervasive environment is growing. However, distributing contents in such environments taxes wireless network operators substantially. To provide the content distribution service in a reasonable cost, we pay attention to user-deployable WiFi access points (APs). In this paper, we propose a decentralized and autonomous content overlay networking (DACON) architecture for the pervasive content distribution services, which is the overlay network architecture comprised of public WiFi APs. We identify and answer major challenges in realizing the content distribution service in the pervasive environment by exploiting the overlay network of public WiFi APs.

Virtual WiFi network database construction for positioning services

WiFi-based location based services (LBSs) are expected to be more and more pervasive in future Internet. In WiFi networks, a virtual network database (VNDB), which maintains the estimated locations of access points (APs), should be constructed for the localization. Since the quality of the LBS is mainly determined by the location accuracy, it is essential to maintain accurate VNDBs for the LBS. In this paper, we propose two novel filtering methods to construct accurate VNDBs for the WiFi-based localization: RSS filtering and grid-based filtering. Experimental results on a real testbed show that the proposed methods construct a VNDB accurately and localization results with the accurate VNDB are comparable to those with a real network database (RNDB).