Browsing by Author "Kim, Sangmin"

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    The Internet Topology: Illusion and Reality
    (2008-12-04) Kim, Sangmin; Khaled Harfoush, Committee Chair; Arne A. Nilsson, Committee Member; Carla D. Savage, Committee Member; George N. Rouskas, Committee Member
    Research studies targeted at unveiling the Internet topology are essential for understanding the performance of the Internet and its resilience to failures or distributed attacks, and for generating realistic topologies to simulate Internet protocols and applications. An accurate understanding of the complex Internet structure and behavior, while very rewarding, is very challenging and in fact is a source of controversy in the networking research community. Till now, there is a lack of understanding of the Internet complexity In this thesis, we make the following contributions. First, we propose an efficient tool, AROMA, to unveil Layer-3 maps of the Internet and use it to reveal ISP maps. AROMA reveals the same number of routers and links as existing tools such as Rocketfuel after sending less than 5.1% of the number of probes used by Rocketfuel, and reveals at least 100% more links and routers than Rocketuel while using the same number of probe packets. Second, we study the limitations of existing layer-3 tools such as traceroute in unveiling the details of the Internet structure and identify that the power law connectivity observed in the Internet topology is not an illusion as suggested by some researchers. It is mainly manifested due to the blindness of traceroute to layer-2 devices, and this manifestation will persist independent of the nature of the underlying physical topology. Third, we provide a realistic Internet topology model, HINT, which captures the Internet structure and features. HINT is based on economical, performance and security constraints that are typically used to construct networks. Matching HINT topologies to known ISP topologies confirms its superiority to existing Internet topology models.
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    Source Driven MPLS Multicast
    (2003-07-24) Kim, Sangmin; Khaled Harfoush, Committee Member; Rudra Dutta, Committee Co-Chair; Arne Nilsson, Committee Chair
    As demands for multimedia service grow, the functionality of multicasting is more important. With multicast we can reduce resource consumption and the load on a server. The saved resources and computing power can be used for other purpose. A new multicast protocol, so called Source Driven MPLS Multicast (SDMM) is suggested as an alternative in this paper. This protocol utilizes the IP option header for multicast group management and the MPLS technology for multicast tree building and packet forwarding vehicle. Since multicast group management is done by the server itself unlike IP multicast, the server can control overall multicast tree. Other benefit from SDMM is that its group management is more flexible than IP multicast because multicast address in SDMM protocol is arbitrary assigned by the server and the number of the address is multiple for a service. With these properties in SDMM, the server can directly control the dynamically changing service request, and satisfy the diverse demand from different service group.