Projects | |
| Measuring Routing Stability in the Internet | |
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Previous measurement studies used either BGP update counting or otherwise grouping updates into events to quantify routing stability. However those measured do not necessarily reflect the routing stability as experienced by network users or applications. In this paper we propose a new metric that takes into consideration both the number of routing changes and the timing of those changes. We demonstrate the advantages of this new metric and apply it to collected BGP logs to quantify the routing stability observed from multiple vantage points. (This work is now under submission.) | |
| A Study of Global Internet Routing Stability using Link Weights | |
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BGP routing data analysis can be challenging due to the large data set size and many factors affecting it. However in this project, we exploit the fact that 1) there are many observation points (OregonView and RIPE RIS) and 2) large set of data carries mostly redundant information. With these thoughts in mind, we use a concept of link weights and PCA (Principle Component Analysis) technique to reduce the dimensionality of the data set in order to better understand the dynamics of the Internet. I started working on this project since Aug. 13, 2007, and in these days, I spend a lot of time processing/plotting BGP routing related data. (This work is now under submission.) | |
| LinkRank | |
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Due to its large scale and size, it is not so easy to figure out what is going on in the Internet although BGP routing data through OregonView and RIPE RIS are readily available. Using this cool tool, one can easily find out what has happened in the Internet without much effort. This visualization tool can be used by BGP operators to understand routing dynamics as well as by people who want to learn more about BGP. LinkRank summarizes megabytes of BGP updates received from collection points and produces easy to understand graphs indicating the segments of routes affected. LinkRank captures routing dynamics in the form of a Rank-Change graph which shows clearly which AS-AS links have lost routes and which ones have gained routes. I joined this project when I first came to UCLA, and my task is to add more features and to make optimizations. | |
| Packet Passport System | |
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Packet Passport System is an on-going research project of my colleague Xin Liu at UC Irvine. It provides unspoofable source identifiers inside packets in the Internet. Since every packet carries unspoofable identifiers and can effectively be located, this can be used to solve origin inference problem in current DDoS solutions. In this project which I partially joined in the late phase, I worked on evaluations of different DDoS defense systems with/without packet passport system on a emulation testbed called DeterLab. | |
| Dandelion: Cooperative Content Distribution with Robust Incentives | |
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This is a project of my colleague, Michael Sirivianos. In this project, we want to improve robustness and fairness in P2P systems, and for that reason, we propose Dandelion, a system for cooperative (peer-to-peer) distribution of paid content. Dandelion explicitly deals with a crucial issue in cooperative content distribution. It provides robust incentives for a client to upload content to its peers, regardless of whether its peers have content that interest it. A client that honestly serves its peers is rewarded with credit that can be redeemed for monetary rewards such as discounts on paid content. Since credit in Dandelion corresponds to real monetary value, it is imperative that the content provider can reliably keep track of a client's cooperativeness, without running the risk of its clients manipulating the credit mechanism. In this project, I mostly worked on evalutions of the system on Planetlab testbed. | |
| Free-riding in BitTorrent Networks with the Large View Exploit | |
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We study the behavior of BitTorrent networks in situations where selfish peers attempt to maintain high download rates without uploading. We use experiments in both public torrents and private torrents residing on PlanetLab to show that a client can free-ride and still attain performance equal to or better than protocol compliant clients. Our experimental results show the following: a) our modified free-rider client can achieve better download rates than a protocol compliant client in most common-case public torrents; and b) in ~300-leecher PlanetLab-residing torrents that consist of 10% free-riders, free-riders on average outperform compliant clients, while they perform slightly worse than clients in a swarm with only compliant client. Our results suggest that the large view exploit is effective and has the potential for wide adoption. | |
| Molecular Communication | |
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This research explores the possibility of molecular communication as a solution for communication between nanomachines. Nanomachines are artificial or biological nano-scale devices that perform simple computation, sensing, or actuation. Molecular communication provides a mechanism for nanomachines to communicate over a short distance (adjacent nanomachines to tens of micrometers) using molecules as a communication carrier. Current research focuses on understanding biological nanomachines and also on artificially creating counterparts of biological nanomachines. No current research focuses on communication aspects of nanomachines. Communicating nano machines can spur the creation of entirely new applications such as a nano-scale distributed computing system or a nano-scale sensing system. The class of molecular communication systems considered in this research consists of sender nanomachines, receiver nanomachines, carrier molecules, and the environment that these operate in. Senders and receivers include biological (such as cells) and biologically derived (such as molecular motors or sensors taken from biological systems) nanomachines that are capable of emitting and capturing carrier molecules (such as proteins, ions, or DNA). The environment is the aqueous solution that is typically found within and between cells. In this project, I designed/implemented three different types of Ca2+ diffusion simulators to better understand the behaviors of Ca2+ as a messasge messenger in the communication system. | |